1987 300SDL with 230,000 miles of which 25,000 miles I put on myself.
I am having a "fuel injection problem".

My problem is that I can not get the injection pressure to pop the injector and get the fuel into the cylinder.
I have the injection pump timed at 15 degrees after top dead center with the "vee" right in the middle of the governor's hole.
I even went further and did the drip test, using an injector line and at 24 degrees before top dead center, the fuel sat there and dripped about 1 drop per second for at least 35 minutes and would have continued if I had not turned the engine using the crankshaft bolt.
I've tried loosing the injector seal and measured the amount of fuel pumped using vinyl tubes attached to each injection pump fuel outlet.
The fuel would flow as much as I wanted it to.
To gushing out to fill the vinyl tubes quickly, (a few tries of turning the switch), to hardly any fuel being pumped, based on how tight the injection pump fuel outlets are tightened.
The fuel would pump through the injection pump, but would not build up enough fuel pressure to activate the fuel injector to inject the fuel.
To test to see if fuel was being ejected into the cylinder, I used a fuel line and attached an injector and turned over the starter and look for fuel injection.
And though fuel would pump, I've had no success getting the fuel to build up enough pressure to inject the fuel.
Can anyone help me solve this problem?

Thanks in Advance

BenzDiesel

I...Anyway, I've learned alot about Mercedes Diesels to include having experienced the "run away" engine, which in my case was caused by the oil case being over filled with diesel fuel, which I don't know exactly what caused the fuel to flow into the oil crankcase....

Sorry I don't have a lot to offer on your pressure issues, but one thing that jumps out at me is do you think it is related to your fuel-in-oil problem? Have you checked to see if your lift pump is working properly? Seems like either lift pump or internally in the IP would be the only places for fuel to get into the oil in large quantities. May be wrong though.

You say you've done everything, but I didn't see mention of having your injectors tested. Could it be as simple as a defective injector?

Habanero,

I replaced the injection pump. And the answer to your question is yes, the cause of the over fueling problem HAD TO BE the injection pump, which I replaced.
Anyway, thanks

BenzDiesel

The cause of your fuel getting into the oil didn't "HAD TO BE" the IP, it could have been the lift pump, which may or may not have been replaced along with the IP.

It sounds like you are more interested in griping than finding an answer, so I will end my troubleshooting at this point.

Old300D,

No, I didn't test the injectors. I used "test" injectors that were known to be good.

BenzDiesel

I didn't mean to bring up the obvious, but I read you attached injectors to the new IP and cranked it. You had fuel flow from the pump, but none out the injector -- that's the only reason I mentioned bad injectors. It sucks that you are "guessed out", but given Mercedes parts are already expensive, I'm again stating the obvious that shot-gunning the diagnosis can end badly.

I've tried loosing the injector seal and measured the amount of fuel pumped using vinyl tubes attached to each injection pump fuel outlet. The fuel would flow as much as I wanted it to. To gushing out to fill the vinyl tubes quickly, (a few tries of turning the switch). To hardly any fuel being pumped, based on how tight the injection pump fuel outlets are tightened. The fuel would pump through the injection pump, but would not build up enough fuel pressure to activate the fuel injector to inject the fuel.

To test to see if fuel was being ejected into the cylinder, I used a fuel line and attached an injector and turned over the strarter and look for fuel injection. And though fuel would pump, I've had no success getting the fuel to build up enough pressure to inject the fuel. Can anyone help me solve this problem?



Since you have utilized multiple injectors and two different injection pumps, I am going to conclude that neither of these components are the problem.

Therefore, the only possibility is the procedure utilized to install and remove the hard lines from the injection pump. The statement that the fuel is variable depending on "how tight the injection pump outlets are tightened" does not seem proper to me, however, I don't have the experience with this engine.

I will ask Peter to make a comment about this for you.

I'll be listening. Haynes did an excellent job on the manual for 617 engine. But I guess the information has been kept from them as well or the reward of preparing a manual to cover the 603 is not worth the effort in terms of reward on investment that it would take to produce a good quality book covering the vehicle in such great detail, as they did on the 617. And I believe that the 603 engine operates and was built on the same principles as any diesel engine, especially the 617. The concept of compression, fuel and air and the engine should run is basic in all diesels. Even if the engine didn't start, the fuel should pump. And on the 603 injection pump, the degree in which you tighten or loosen the injector seal holder, you know, the cap in which the fuel line enters the injection pump, will vary how much fuel is pumped out of the injection pump. But this aspect is not the same on the 617 pump, which is rigidly tight. Which brings me to, should the cap or seal holder be as tight on the 603 pump as it is on the 617. Areas like this is where the information is rare. Nobody seems to know the intricate operating functions as to what is "supposed" to happen. I will look forward to hearing what you can find out. Old300D suggested it could be the manuel fuel pump, but as I understand it, that pump is supposed to pull the fuel to the injection pump; and it does that and once the fuel reaches the injection pump, somehow the fuel is pumped with pressure. I've checked to make sure all lines are tight with no leaks, especially the plastic fuel line from the pump to the fuel filter area and the small things like that. Is there some electrical component that activates the injection pump pressure? These are the answers that I'm seeking. Diesels are supposed to be "simple".

BenzDiesel

Hello BenzDiesel
Suggest:
Unbolt lift pump, leave lines connected, use large channel locks to depress plunger twenty or thirty times, look for plunger leak, listen for squeak of fuel bypass, remount lift pump.
disconnect injector bypass hose from fuel filter housing, cap fuel filter housing fitting, watch for fuel from the bypass hose and crank engine.
Remove or disconnect the TRAP and try starting.

t walgamuth,

Thanks for your positiveness. Believe me, I've looked for the simple, easy to overlook things. I've done the hard things, as well. And am back to looking for a simple thing. I've done my best to cover all of the bases, to include having changed the head, the fuel injection pump, the turbo, the air flow sensor, the over boost protector, EVERYTHING, even the RPM Sensor!. And right now, I'm where I just can't get the fuel to pump THROUGH the injectors. However, whunter has a post, which I am going to respond to next that gives me some additional hope that I am on the right path. As I've said, I've been all the way around the world on this car and diesels are supposed to be simple and straight forward. You get the fuel, the air and compression, and you should hear the car run, even if it runs badly, at least it should start and run. Oh, yeah, and I've checked the timing. No stretch on the chain, at all. The marks on the cam and the cam holder line up, perfect. On the compression stroke (I know it is the compression stroke because I plug the glow plug hole and turn the crank until the plug, a piece of napkin, pops out of the hole when compression forces it out) is at zero TDC and the "vee" in the governor hole on the injection pump lines up at 15 degrees After TDC on the compression stroke, and I get one drop of fuel per second at 24 degrees Before TDC for at least 35 minutes, tested (a steady drip, drip, drip, drip). So, believe me, I've checked. Now, I'm looking to what I need to do to close the deal, UNLESS somebody can show me what I did wrong as to checking the timing or ANYTHING else. And a low compression engine should run, even if it smoked like a train and I've seen that too, during the "run away". But I think whunter has the answer, maybe, and I'm about to ask him a few questions based on his suggestions as to what approach I need to take to solve this problem. And when "confusion" sets in, you just don't know which way to turn. And right now, I'm turning in circles and just need somebody to tell me when I can stop turning and spinning in circles. The 603 is a very "easy" engine to work on.

BenzDiesel

whunter,

Thanks for replying and for giving me a plan of action based on the step method to diagnosing a car problem. "IF" I need to use channel locks to depress the plunger, then "THAT" could be my problem! I just unbolt the two ten millimeter nuts and just pump away using my thumb to get the fuel to the fuel filter, similar to how the 617 auxillary fuel pump works. Now if on a good auxillary fuel pump, channel locks are needed to depress the plunger, and that pump facilitates "building" pressure in the pump and on through to having enough force to pop the injectors, then I could just have an "auxillary" fuel pump problem, which I really do hope that is the problem. Again, should I be able to depress the pump with my thumb, as I have been doing?

If it not the fuel pump, my next question is: "Listen for squeak at fuel bypass"?, could you elaborate on this? And do you mean (referring to the injector bypass hose) disconnect the "metal banjo" end of the plastic fuel line hose at the fuel filter that leads to the back side of the injection pump, which has the braided, small fuel return lines leading to the #1 injector "side" over flow valve?

"Cap fuel filter housing fitting, watch for fuel from the bypass hose and crank engine." What do you mean by "cap" fuel filter housing? Fuel from bypass hose? Do you mean at the small braided hose end? Or at the banjo? Could you elaborate?

"Remove or disconnect the TRAP" What TRAP?

I really do hope it is as simple as the auxillary fuel pump. This car has almost killed me trying to get it to run right.

And thanks for your reply.

BenzDiesel

ok here goes, if i had no output from an injection pump i would loosen the fuel line that supplies fuel from the fuel filter(secondary=big one)to the ip,crank the engine and see if it pumps fuel.if no i got to fix the fuel pump or the fuel lines or put some fuel in the tank. if yes i would retighten the fuel line i loostened,i would then loosten the return fuel line from the ip and again crank,i should see fuel there also but controlled by the relief valve at the ip pump. the ip needs it fuel to be under pressure and if the relief valve dont close at the correct pressure it just wont work right.
assume i have fuel to ip,fuel from the ip then i have to know the ip is being turned,assume its being turned,i have to remove the top most fitting on the ip after the pressure line to injector has been removed,this is the check valve to hold pressure on the injectors while engine is waiting for the next firing,these valves not holding will cause no starting to very slow starting. now i take a straw and place it down to the power plunger of the ip where i removed the check valve assy, again crank the engine, i should see the straw work up and down about 1/4 inch.
assume all test have passed the test,then i probably call my self a few choice words and go back and pull the vac shut off line from ignition key(usually the brown one) off the shut down valve and again crank the engine and listen to the clatter-clatter.
course i would have to know my compression.
hope this helps
larry perkins
71 old cars

As I said, I even used clear, vinyl tubing about 6 inches each and placed on each injector outlet on top of the pump. I'm getting fuel pulled up from the tank to the first fuel filter to the fuel pump to the main fuel filter to the injection pump to the injection pump fuel outlets (where I had the vinyl tubing attached to each injector outlet) which let me "SEE" the quantity of fuel being injected into in fuel line and consequently into each cylinder, when the car would actually be running. My problem is the not enough pressure, which I think whunter "precisely" diagnosed. I didn't know BEFORE HAND whether the injection pump produced the pressure or was it the auxiliary fuel pump. And according to whunter, that little auxiliary should be pushing the fuel with a lot of force. He hasn't responded yet, but I will be checking the fuel pump, without doubt.

But my question for you is: What and Where is the pressure "relief valve?" I've heard that the fuel filter regulates the pressure. That is all I need. To know what mechanisms produce fuel pressure in the system.

BenzDiesel

benz i am starting to suspect that you are just playing a prank on us,but for sake of me being wrong i will answere your question.
the aux pump produces low pressure to get the fuel to the ip(i think about 10 psi but read if this is important to you), the ip produces high pressure(probalbly about 2500 psi,again read if its important)
the pressure inside the inlet side of the ip is maintained by the fact that the aux pump is working and that the relief valve that is located on the back side of the ip(its screwed directly into the ip pump housing and has a plastic line attached to the fuel filter,it must not be open until it has about 7 psi(again read if its important)take a light and shine in between the ip and the block and you can see.
also would you state your compression values as you have done all that i earlier wrote about?
larry perkins
71 old cars

The high pressure for proper injector pop is built up between the plunger/barrel (element) and delivery valve. The feed pump simply feeds the reservoir surrounding the elements within the IP. The pressure relief valve is on the engine side of the IP, where the return line leaves the pump on its way to the fuel filter, and on back to the tank. The banjo bolt back there needs to have a ball and spring in it, or it can't keep the IP reservoir properly primed.

What you just stated goes basically against the grain as to what whunter said, unless it takes channel lock pliers and definitely more than thumb pressure to activate the pump to keep the ten pounds consistent. What you stated about the low pressure function of the pump is what I thought. This was a known good injection pump and had worked for me prior to being installed. Do you know if you are supposed to be able to pump the auxiliary pump with your thumb? The pump mechanism just rides on the injection pump crankshaft, (correction) camshaft. Do you know how the pressure is built up in the injection pump or how the pressure relief valve (fuel line) functions? This line on the back side of the injection pump is one of the issues that I asked whunter about in my reply to him. My compression issue has nothing to do with solving this problem, in my opinion, and I will not even go there because that is not going to help me solve this fuel pressure issue BECAUSE it can easily lead back to "guessing", which I'm not going to do. I can tell you that 350 psi was the highest reading that I got. And I adhere to the philosophy that it is best to take a warm engine read to get a true picture in terms of engine compression and a cold engine numbers can be misleading. Does engine compression and fuel pump pressure work off of each other?


BenzDiesel

Never had much reason to remove a 603 feed pump before (they don't often fail), but I just went out to my shop and pulled one from a spare pump. It pushes easily with one finger.

It's really not a crankshaft in the pump that drives all the action, it's a camshaft--this pretty well explains how pressure is built up and delivered to your injection lines:

http://users.zhonka.net/zeitgeist/MB%20Repairs/OM603%20injection%20pump/Bosch%20Inline%20pump%20diagram.JPG

back side of the injection pump. Thanks. I'm open to checking out ANYHTING that has a chance to help me solve this low fuel pressure issue. And I was thinking along the lines as you just stated about function of the barrels inside the injection pump producing the pressure. That is where those copper gaskets would come into play, just trying to figure out what is going on without having concrete data and information relating to the Bosch injection pump. I know that I can loosen the valve seal holders and get plenty of fuel. I just can't get it to pop pressure, where I can see the fuel being injected "outside" of the engine, which I would think should be able to be acccomplished and also know that I could be wrong. But everything I've read states that the injection pump is a mechanical pump, but then again the 603 pump has an electrical component (idle control) at the very back of the pump, which I don't know how the big red idle control, electro mechanical mechanism functions in relationship to affecting fuel pump pressure. Again, thanks and any relevant information is very well appreciated by me and will be checked out.

BenzDiesel

When I timed the pump with the the "vee", showing in the governor hole, at 15 degrees past TDC, the barrel was at the "almost" near top in it's recess hole, sort of like a piston looks in a cylinder at almost TDC. If I'm not mistaken, I think number 1 was at TDC or on the injector compression stroke when I timed the engine. I even asked myself a question? When the engine is going to TDC on the compression stroke, does the injection pump need to be timed to be injecting fuel for the INTAKE stroke that will be receiving fuel in relationship to the #1 cylinder's heading toward TDC. In other words, does #1 TDC at the engine match the #1 TDC in the injection pump or should TDC in the injection pump be matching the correlating INTAKE stroke? And thanks for correcting me and calling it a cam and not a crankshaft in the injection pump. But do you understand what I am asking? Because looking at the lifters in the cylinder head, when #1 is going up on the compression stroke in the engine, I think #3 be at the INTAKE STROKE. I will have to go back and recheck. But you can see the issues that I've seen, but have no concrete data to know what should be. And believe me, once you see a diesel in "run away" mode, you will not be hooking up or reinstalling that injection pump again, even if Bosch men came in person and told you that the injection pump was good.

BenzDiesel

benz,for your reference, just because an ip can be timed and appear to be functioning doesn't mean it will pump fuel, the pressure plunger that produces all the high pressure is shoved up by a cam shaft in side the pump but is returned by a spring. i have disassembled a lot of ip's that have all the plungers stuck up and you ain't going to get a drop of fuel till you get the plungers back down. this is why i mention inserting a straw so you can see the plunger move up and down. you get that motion with fuel available and you have to get small volume under high pressure.
larry perkins
71 old cars

With H202 diagram, I have a little more to work with. I've got to study that diagram and find out what is the "firing order" for a four cylinder engine as it relates to the diagram. This diagram is the kind of information that I have sat here ALL DAY searching for. But thanks again, and you can bet that I will be taking into account what you just said and make cetain that the barrels are doing what they should be doing. At this point, anything less than having to TAKE DOWN HEAD #11, I'm all for it, because I will do a #11, if I have to.


BenzDiesel

Can you post any instructions as to how your manual says the injector pump should be installed? Especially showing the relationship as to on which injection pump cylinder should be firing or is at start of delivery as the engine is moving toward 15 degrees After TDC on the engine's compression stroke. Any information will be appreciated. I'm inclined to believe that as the engine goes toward the #1 cylinder's compression stroke, the injection pump should be timed to the "relevant" INTAKE stroke (number three, I think) and not timed to the #1 cylinder, unless at 15 degrees past TDC on the compression stroke "IS" the beginning of the INTAKE stroke. Do you understand what I'm trying to ask? Thanks.

BenzDiesel

1 revolution of the IP is all you get to fire all 6 cyls. That diagram doesn't show the 4 elements of one 4 cyl. pump, rather it shows 4 different stages of fuel delivery for a single element--any single element.

If the governor "vee" ridge is showing in the little threaded "window" the pump is somewhere around the start of delivery point for #1 cyl--i.e. it can't be for any other cyl that's 180 degrees out. Make sure both (cylinder head) cam lobes on #1 cyl are pointing up when you set the start of delivery for that cyl. I use 14 degrees ATDC for my rigs, but that's just me.

I will be doing all of the checks that have to do with that injection pump. And I really do thank you for posting that diagram. I know my pump is timed with the "vee" at 15 degrees ATDC on the compression stroke (I'm fairly certain). I will have to check to make certain that both lobes on the engine's camshaft are pointing up at 15 degrees ATDC or there somewhere near both camshaft lobes pointing up, which I think they should be, unless when the mark on the engine's camshaft and the pointer on the #1 journal camshaft holder are in alignment, it is possible to be at some place other than TDC, 180 degrees out and as the piston was moving up, it blew out my plug in the glow plug hole, but the engine was on another stroke other than the compression stroke. Is that possible to have the marks aligned and still be out 180 degrees? Again, thanks.

BenzDiesel

benz i havent had the privilege of talking to any mb engineers but i would bet a nickle against a donut hole that the eng located the port on the pump for convenience(so you could see it and be able to insert the light tester) and all that worked out to 15 deg atdc and its just a bench mark. no diesel engine could develop max power with the fuel getting to the cyl 39deg atdc (15+25)
just a experienced guess
larry perkins
71 old cars

Are you saying that the injection pump "vee" needs to be timed (inserted) so that it can be seen in the governor's hole at 24 degrees before TDC? I did notice that 15 degrees ATDC made it easier to insert the vacuum diaphram without having to use force and the slope or curve in the vacuum pump which the roller inside the vacuum pump rides on is grooved or indented at approximately 15 degrees ATDC and the vacuum pump will bolt right up with no problem. Are you saying that 15 degrees is for a purpose like that and had nothing to do with pump injection timing?

BenzDiesel

Just thought of one other thing...though it's remote.

You ARE attempting to start the engine with the engine stop lever in the up position--correct? If it's not all the way up as far as it could go, your fuel rack will not advance enough to allow the control sleeves to rotate and allow the plungers to compress fuel. It's conceivable that the engine stop mechanism has separated inside the governor, keeping the fuel rack in the "all stop" position. One way to check, would be to remove the side cover* on the IP and observe the fuel rack's movements when you move the engine stop lever and throttle arm.





*As a side note, curious diesel geeks with OM60x engines can remove the IP side cover and their ALDA units, then push down on the detent shaft (under the ALDA). Observing the relative position of the fuel rack whilst pushing on the shaft will provide a better understanding of how the ALDA functions. Pushing down limits fuel quantity (e.g. no boost is present), and releasing downward pressure advances the fuel rack (increased boost). You can push down on the detent shaft and move the throttle arm to full, then gradually release detent pressure and observe the fuel rack reach its full load position.

However, it seemed like sometimes as I was trying to start the engine, with the shut off vacuum line connected, the stop lever would seem to be pulled down slowly with vacuum, if the engine didn't start right away. That is why I tested with the shut off disconnected to prevent shuting off the fuel by accident, when my problem is I'm not getting enough pressure in the first place. But I'm not certain if that was actually happening because one day I just happened to notice that at the very moment the ignition switch is turned off, the STOP lever went all the way to the bottom and as the vacuum released, it came back up on it's own. I don't know if it was gradually going down or just went down each time I turned the ignition switch off, since I'm almost always working alone. I even thought that it was a "safety" measure that Mercedes incorporated to prevent too much fuel from being discharged into the engine cylinder in a NO START situation, which would help to eliminate the "run away" condition because of too much fuel in the cylinders, which is one hell of a scary thing! The car sounded like an AIRPLANE on take off. I just disconnected the fuel at the small fuel pump, after the shock wore off after I just stood there momentarily and looked at this monster AWAKEN and it shut off, eventually with a big CLOUD of white smoke rolling just like in the Smoky Mountains in Tennessee on a foggy, cool, winter morning. The smoke was hanging in the air as if it was alive. I didn't get scared until I went to bed that night and started thinking all of the "WHAT IFS" as I was about to try to go to sleep. And that is why I left the "electrical" control functions questions on the table to find definitive answers to.

About that Alda thing, I'm not that sophisticated, yet, but am willing to check it out, since I've been through everything else.

BenzDiesel

benz i am trying to not get you off track, from your earlier post it appears you have the thing timmed right,just double check to see if the camshaft #1 cyl has both cams in the up position(now both cly valves are closed)if you had your drip tube on it should just drip at 1 sec pace at about 24 deg btdc(remember you said you checked it)what i am saying is when the magnet is visible in the port for the light test(read)and the crank pully is on 15 deg atdc the #1 cly has already delivered,so its just a random number and the pump is timmed correctly.
if anyone knows a better explanation please step in.
you are getting close to finding your problem,like h2o2 says either the ip is not asking for fuel or the ip cant pump.
if you get to the straw test for the pressure plunger going up and down you should be able to see the plungers rotate with the stop lever up and working the throttle lever from idle to full throttle.
larry perkins
71 old cars

before i am corrected on the last post,i am not sure if the device thats inside the ip is a magnet or just a piece of steel that triggers the light(the magnet may be installed in the light tester) to solve my problen when setting an engine up i made a tool from a drill bit that fits precise and have checked it with a light tester and it works as close as the tester.
larry perkins
71 old cars

Larry,

I know this and as I said it tested and dripped for at least 35 minutes, but I am going through all of the checks and would be pleased to know that the problem is a simple replacement of the injection pump.

BenzDiesel

The overfilled crankcase was very likely a fuel leak in the IP flooding the oil with fuel. Pretty rough on the engine, that.

There are only two things that will prevent the IP from generating enough pressure to pop the injectors (assuming that the pump itself is OK) -- air in the pump or incorrectly installed pressure valves. If the pressure valves are in fact installed correcly, you will have very little fuel delivered for each pump stroke even with the control lever all the way over to full power -- total delivery is less than 100 uL per stroke at max delivery. This is a couple drops, so if you are expecting much more than that, you may think the IP isn't working. Fuel won't flow out of the IP with the pressure valves installed and the holders torqued down, it takes a couple hundred psi or so to lift them. This is so that the falling plunger will pull fuel into the sleeve while the line stays at pop pressure. Delivery will be restricted to the volume the governor is calling for.

If the pressure valve holder seals aren't sealing (this is a problem with this particluar pump not seen much in the ones on the 617 engines), you will get normal delivery with the injector cap nuts loose, but none to speak of actually injected, since the pressure in the line leaks off between IP plunger strokes. The line must stay at just below pop pressure so that the fuel is delivered as the plunger in the IP rises, otherwise injection will be very late.

I'm pretty sure you bleed the air out while testing the IP timing, but you need to be aware that this pump is known for holding air. It's possible that you have air in the lines as well, and this will prevent injection til you get it out.

Here's what I would do:

Install pressure valve holders by the book -- pressure valve goes in the holder with the spring on the stem, pointing up. New copper seals are a good idea, as they harden in use and can fail to seal if reused. If the pressure valve holders are factory installed, leave them be.

Loosen the injector lines at the injectors enough to let them leak (about 1/2 turn), and then crank the engine with the accelerator floored until no more air comes out. This may take a while, and at least one charge on the battery. When you have air free fuel, tighten the cap nuts (they don't need a huge amount of torque), recharge the battery, run the glow plugs, and attempt to start. Don't crank more than 30 seconds at a time, and allow the starter to cool off between cranking sessions, you don't want to have to buy a new starter, too!

It will eventually start.

I suspect your problem is air in the pump, lines, and injectors, and the only way to get rid of it on this engine is to crank it forever.

One other thing to check is the condition of the lines on the suction side of the lift pump -- they are old, hard, and likely full of cracks by now, and if so, you are likely sucking in as much air as fuel and pumping that directly to the IP. You won't get enough fuel delivery to purge the lines until you get the air out of the fuel filter, plungers, and IP body.

I wish Benz had left the lift pump on this model -- I'd rather hand pump for half an hour than crank the engine that long....!

Peter

I'm in the process at this very moment of checking to see how the plungers in the injection pump correlate to the 15 degrees ATDC and the engine's cylinder intake stroke. I'm trying to fully understand the illustration that H202 posted. I will test for the air in the system when I get back to that point. According to initial Mercedes Benz design or Bosch's design, this pump is supposed to bleed itself of air. And I know that once I get everything back RIGHT, the engine will start and bleed itself of air and I won't have to run a battery down in the process. I'm discharging batteries because there is a problem, somewhere in the fuel system. When I get it right, it will start right up like it is supposed to.

BenzDiesel

the 603 injection pump is rough to prime properly and if you have an air leak it will never develop the necessary pressure to open the injectors.loosening the pipe unions slightly at the pump will allow fuel to bypass the pressure valves and give you a false impression.if you can find an old VW filter assy with integral prime pump you can hook this into the supply fuel line loosen one of the pressure valve holders and prime the pump till air free fuel flows.i use this method now whenever i must work on the injection pump or injectors. :)

I see where the injection pump is syncronized with the cam shaft in terms of the engine's firing order. And it is possible to have the injection pump out of time and still have it installed correctly at 15 degrees After TDC as it relates to the engine's firing order, but don't know if the engine would run properly if the pump and engine camshaft weren't syncronized. The process is slow but it's going. I'll definitely be checking for air leaks once I'm satisfied that I have the injection pump and the engine's camshaft on the same page. And you are right, it's rough, when all of this expensive metal will not come together and do what it was designed to do.

BenzDiesel

on this pump there is port on the side whereby you can lock in the correct pump timing.
a special tool is required.
however i understand that an appropriate size bolt will work.
once the pump is "locked" and your crankshaft is at 15 degrees the engine is "timed".
i really beleive you have an airlock in this pump.
a similar situation almost drove me to the brink last year.
cranking the heck out of it will bleed the system but you run the risk of damaging your starter and your neighbours nerves ;)

Hello BenzDiesel well working on heavy equipment in order for the injector to pop it had to have at least 250 pounds have ya thought maybe pull one out turn one of the line out give it a few cranks to see what kind of spray it putting out it would be strange for all the injector be bad unless water got into them i know one thing is the pump and the injectors don't like water to well and check the tip of the injector see if it still has a good tip on them and if ya do have to take the injector apart there not hard just be sure you dip the part in a mix of diesel fuel and gasoline check for any scaring and the plunger should have a tight fit with no dragging you know that the pump only shut down pressure so you can shut down the engine

The timing issue is quite simple. Bosch added a hall effect "nipple" to the governor assembly to permit dynamic timing, and it just happened that the "nipple" goes past the point where they could put the pickup sensor hole at 15 degrees after TDC. The pump actually operates exactly like earlier ones. This was done in 84 or 85, as some later W123 models have the same setup. Some W123 turbo IPs were assembled with the injection pump cam 180 degrees out, but none of the 603 pumps have this quirk, so if it's set at 24 degrees BTDC by drip method and 15 ATDC by hall effect pickup, the timing is fine.

That IP with no hand pump can take FOREVER to purge when empty, much worse if you changed the fuel filter as well. The only real cure is to crank until it finally gets the air out, and if you have fuel and air coming out of the injection lines, it's purging, keep cranking. It's rather unlikely you will get it to start on one battery charge, and if the suction side lines are leaking air in, it won't start until you replace the lines. It will run with leaking suction lines, but if you ever get enough air into the pump to prevent easy starts, it won't prime well enough with the air leaks to ever start.

Peter

Hello BenzDiesel
I suggested the use of channel locks because not everyone is strong.
One of my friends owns three diesel MB and has Multiple sclerosis.
RE: Whunter mentioned trapped air and the auxiliary fuel pump could possibly be the culprit. But then H202 had a spare pump and confirmed that channel locks were not needed to depress the auxiliary fuel pump's plunger mechanism.

Hello BenzDiesel
I suggested the use of channel locks because not everyone is strong.
One of my friends owns three diesel MB and has Multiple sclerosis.
RE: Whunter mentioned trapped air and the auxiliary fuel pump could possibly be the culprit. But then H202 had a spare pump and confirmed that channel locks were not needed to depress the auxiliary fuel pump's plunger mechanism.


OK whunter,

About the pump, it takes some pressure to depress the plunger, but most mechanics, if not all of them, should be able to depress a plunger on that particular pump with ease and I still have that as the potential culprit. If the mechanic can't handle that pump there is no way he is going to be tossing a 603 cracked head around. As always, I'm thankful for any information that even has a chance to be beneficial in solving my fuel issues.

BenzDiesel

Sorry I couldn't read every long rant, so forgive me if this has already been answered:

1) WHAT EXACTLY makes you think there is no fuel being delivered from the injectors to the prechamber?

2) How long have you cranked the car with your foot on the floor? When I replaced my head it took something like 3 minutes of cranking before it fired. That's with a totally dry fuel system.

3) You're saying the *bottom* of the inejctors are BONE DRY?

4) Did you use the proper lock tool to install the IP and then verify timing with the same tool after rotating the engine 2 revolutions?


Please let's stay off the head crack thing - that's way off topic of a fuel delivery issue. Lots of information already out there on the #14 head. Mercedes had a design flaw for the first few years of production (say, through 1988 or so) but the later years were fine (say, 1988-95) and remember that the 603.96x was sold in enormous numbers worldwide, despite low shipments to the USA due to annoying EPA regs. The Finns are routinely getting over 400hp out of a stock 603 long block, so it's definitely not a weak engine design. Driving with a light foot is BAD, btw... worst thing you can do for an IDI diesel is piddle around at part throttle all the time and never rev it over 3000rpm. Drive it like you stole it - frequently.

:rolleyes:

the engine compression does not effect the injector if you are get fuel or not but the engine compression dose effect if you want it it ignite the diesel fuel diesel ignite by the compression and by the cycle compressing the fuel and air so tight that the friction and compression kick the fuel off all low compression will do is puff out white smoke (unburned diesel) SEE on Hazts diesel which is the top of the line German industrial engine the piston goes up in to the head 2mm pass the block surface so that is way timing (it will knock out the valve) is important
on hazts they use a copper ring as a head gasket which i use some lead turn the engine by hand hit the lead then take it out to measure the thickness
hope the help some just remember you getting fuel or you are out of the pump or you might check to see if the pump is in the full open not close or half way close you need to have enough pressure out of the pump to pop the injector springs

I am not getting any fuel to pop the injectors. That is the problem, period. I have to time the injection pump and my fuel injection problem will be solved. I spent all day today hoping to see has anybody else seen what I saw about the inner workings of this 1987 300SDL Diesel. But I guess you have to have gone through that 603 engine backwards and forward like I've done to even know what I'm talking about. Several of the guys here are shooting in the right area, but none so far has said anything to let me know that they fully understand what is going on with this engine from an engineering standpoint.

BenzDiesel

I am not getting any fuel to pop the injectors. That is the problem, period. I have to time the injection pump and my fuel injection problem will be solved.
**sigh**

No. An incorrectly timed pump will still squirt fuel - just at the wrong time. I asked before, and you did not answer, how long have you cranked the engine? Several minutes worth after buttoning up the entire fuel system - yes or no? And have you taken Casey's advice to remove the side cover and make sure the rack is moving out of the stop position?

:computer:

GSXR you have far more patients then I do, I got tired of his long winded complaining by page 3.

BenzDiesel maybe it is time to step back and let the car be for awhile, it seems to be driving you crazy. It is not worth getting that stressed out over a car.

Take the hard lines off the ip and crank to see if fuel shoots out. If fuel is not shooting out you have an internal IP problem. Remove the pump and take it to a diesel shop. They will be able to bench test it and determine what is wrong.

Andy has fought 1/2 dozen bad Ip's on his 300SD and you don't see him complaining.

True but as GSXR said even if the timing is off the pump should still pump fuel. Pete's was 180 degress off and it still ran! :eek:

When you crack the lines are you getting fuel up to your injectors at all?

I will answer your question. Yes, fuel gets to the injectors but only when the valve seal caps are loosened. However, the fuel does not pump with enough pressure to pop the injectors to allow fuel to enter the combustion chamber. Without fuel getting into the cylinder, the engine will not start, regardless if there was 1000 pounds of pressure on each cylinder.

BenzDiesel

Humor me more. According to an another post you replaced the IP? I am assuming it was with a used one and you replaced the delivery valve seals as you were putting it in?

Ok now I am not IP expert but if I was having that problem here is what I would do:
a) When I did my delivery valve seals everything went smoothly their doesn't seem to be much to mess up. So if you followed the procedure they should be fine. Re torque then just to be sure if you havn't already.

b) If that doesn't work then, how do you know the IP you bought was good? Did you hear the previous engine that it was on run? Is their a warranty? I would suspect a bum IP. Now this gets tricky you could do what Andy is doing and get a few used ones and try it that way. Or you could bring it to a diesel shop and have them go through it. I have a good shop in New Haven but you are probably to far away.

Their are little metal plungers inside the IP that build the fuel pressure. It is possible there was water or very bad fuel was run through it destroying the seal these plungers make.

Do you have your old IP around?

Edit:
I don't recall this was about a year ago. But their was a long post about it.

Pete Burton(sp?) is his handle.

Bosch IP's are used on tons of diesels and are among the most reliable out their.

I think after almost 20 years all bets are off. Is it possible Andy got 6 bad IP's sure but not likely. I think his problem lies elsewhere but that is another thread.

What is your theory? So this is the IP that has been on the car for at least 25k miles? Did it do bad all of a sudden or after you did the delivery valve seals?

BenzDiesel from what I have been able to get out of your posts is that you replaced the head. Then you bolted the IP back on with new delivery valve seals because they were leaking. Now you are not getting much fuel pressure to the injectors.

OK redo the seals if you have not already. If that doesn't do it remove the IP and have an injector shop go through it.

benz, i ran into a situation on a 603 that may be some of your problem,i earlier gave up on this thread because of the bs and i am 64 years old and dont have time to go back and read all that has been discussed.
but i do remember you saying you had parked on a grade for an extended time, so there is a possibility that the check valve that is installed in the lift pump(fuel)has gone bad and letting fuel leak back to your fuel tank.
i was reassembling an older 615 engine and noticed that with the ip#1 port open for ip timming that i had a loss of fuel,i pump it up and fill the ip with fuel,dont touch nothing and down it woulg go,so the chevk valve wasnt holding and the fuel was getting sucked back to the tank. first one i seen to do that,but it could be happening to you.
if it were me i would start with a fresh battery,tighten everything up,crank till it starts or 45 seconds pass,clamp the rubber fuel line with a clamp(tank to primary fuel filter)let her set till my starter cooled off and repeat this process,would put a charger on my battery and sorta help it alone.
many ways to prove the check valve is bad but i am lazy and look for the easy way.
72 old cars

1: There are published procedures for installing and timing injection pumps. Experiment at your leisure, but the correct procedure (used by Benz since about 1935) is to set the engine at 24 degrees BTDC (or TDC, I forget) and set the IP marks on the driveshaft to align with the mark on the collar, and install. Should be within a few degrees of correct timing.

2: Diesel engines work by heating the air with compression and THEN injecting the fuel to start combustion, not by compressing an ignitable mixture. They'd have carbs otherwise, not expensive injection pumps, believe me!

Peter

Peter, the 24 BTDC "wet" timing methods are only specified for the OM61x engines. All the OM60x engines use the RIV tools, which measure a different timing point, 15 ATDC. The "wet" method was never officially approved by MB for use on the OM60x pumps, although several people have used it with success. (However, I think only one of the 3 different 'wet' methods works - and I can't remember which it is!) I find the method with the tool is infinitely faster and easier, but I guess some people don't like buying tools. Just don't ever confuse the two different numbers, as the car may not run at all with the timing ~40 degrees off...!

end and reach it's TDC stroke at 15 degrees AFTER TDC on the compression stroke of cylinder #1. It appears according to the diagram that end of delivery in the injection pump would end at TDC starting out from 24 degrees BTDC or at least somewhere close to TDC on the cylinder's compression stroke or looks like it SHOULD or might. Plus, the TDC on the injection pump stroke is NOT the "end of injection stroke" and it might make more sense to have the TDC of the injection pump to end at 15 degrees AFTER TDC, which in effect would have the injection's pump "END OF DELIVERY" ending at ZERO TDC or very near it, which would then make full injection coincide with the cylinder's TDC and would account for the "EXTRA" travel needed for the injection pump to reach from the "end of delivery stroke" to reaching "full TDC", which could be 15 degrees. Anway, it has to be at one of three places at this point for me, which is encouraging although I'm dreading getting back in the fluids.

Anyway, I'll try timing the injection stroke to end at TDC at 24 degrees BTDC of the compression stroke "if" this ending at TDC at 15 degrees ATDC is not correct.

BenzDiesel

It seems like the pump just "jumped" out this time. Anybody with concrete advice and would like to jump in and invest in this endeavor, just go right ahead. I'm wondering if 40 degrees BTDC is the full travel from injection pump BOTTOM DC to it's TOP DC.

BenzDiesel

Benzdiesel, the IP should start to inject at 24. I think that's what psfred was saying.

Thanks
David