new to me 87 300TD - PeachParts Mercedes-Benz Forum

Quahog · #1 11-10-2012, 08:04 AM

Hi All,

I have purchased Shirtex's #17 head w/ fairly rust-free wagon attached & am going though it, fixing the most pressing problems, namely #2 cylinder not firing. The idle is very rough w/much white smoke (doesn't smell like coolant) from exhaust. Seems to smooth out @ higher rpms.

What I have done/learned so far:
- replaced leaky DV seals,washers & incorrect #2 spring w/MBZ parts
- yoinked GP's, all glowed strong when energized
- had #2 pop tested, fuel came out of returns before even hitting 1000psi, but perhaps the jerky diesel tech didn't tighten it back up properly after showing me the effective way to open them up. ( I was doing it wrong)
- took apart & cleaned #1 & 2 injectors (remans) found french-made nozzles
- swapped #1 & 2 - problem stays with #2, cracking line smooths it out
-read 100's of threads using the seach feature

I think an Italian tuneup might help, but need to fix ball joints & rear wheel bearing first - fastlane parts are on the way.

My main questions for the present:
Will EPC work on a mac? I know its not supported, but I don't don't want to go to the dark side to get it.
What paper manuals do folks find most usefull/available for reasonable cost? I like being able to prop them up on a fender while I work. Also the grease-stained pages serve as bookmarks & reference for what I have done.

thanks in advance

scottmcphee · #2 11-10-2012, 08:25 AM

Cracking the line on number two smooths it out? So power in the hole is a bad thing, with the white smoke that's not coolant smelling. Rings, blowby, hole in the piston, valve seat or seals? What does a compression test on that hole read?

barry12345 · #3 11-10-2012, 09:26 AM

Sounds more like the sequential timing of the injection pump is badly off for the number two cylinder or the injector is bad. You have eliminated the injector as a source.

Smoother sounding with the cylinder disabled is the indicator of this. I was also trying to figure out another possible cause but it is not happening. What I would be looking for is an indication that the cylinder is indeed running hotter by the milli volt method first of all. If it is. Mark the element positon well for a refferance point to return it to and try adjusting the element.

I would use the mili volt method as I suspect that cylinder is running very hot by injecting early. Without using the milli vots you would not be certain of that. That also is good in a strange way if so because it means the element for that cylinder is still capable of reaching pop off pressure. In a situation as severe as yours making the voltage from two new glow plugs the same by adjusting the element on the number two should be a major improvement. Remember to mark the start position of the element you are going to adjust though.

I also would not drive that engine as is too much. We have never had a hole burnt in a piston yet to the best of my knowledge. When you had the injector out did you look at the pre chamber? The symptoms are wrong to me for a camshaft or valving issue is my feeling. I could see the white smoke if the injection was extremely late but the engine would not run rougher with the injector on line.

One last thought would be to look at the camshaft lobes etc for that cylinder first though. I suspect they are okay and on average would not cause your symptom yet it never hurts to check. I also realise there are repeat issues in getting the delivery valve operating properly on this models pumps. It just strikes me that early injection on a cylinder is not one of them but truthfully I do not know.

What am pretty positive of and it is a good thing. Is the internals of the engine for that cylinder are probably with a certain amount of good fortune not the issue. The white smoke with the cylinder activated although an indication of something I would forget until I saw what the milli volts are indicating. Although the presence of it is troubling. If the cylinder is running colder than the others do not adjust the number two injection pump element.

vstech · #4 11-10-2012, 03:53 PM

white smoke at idle and under acceleration, is usually a lack of air getting into the cylinder. I'd pull the valve cover, and verify the intake lifter on #2 cylinder is not damaged or collapsed.