85 eta rough misfire black soot from exhaust

[2.5-12]

well, shit.

swapped fuel rail, fuel injectors, FPR from my perfect running ETA and it still runs like a big pile of donky faluces.

pulled off the upper timing cover to check timing, that was a-ok.

swapped distributor cap, wires again too just to check. nothing.


car still hard starts, will die if accelerator isn't prodded gently most of the time. If I unplug the ICV, the car will idle search but it won't die. when I do this, exhaust is visible. assuming rich fuel mixture.

I think I have now replaced everything.

what. the. fuck. is this car trying to do to me?

[dnguyen1963]

I feel for you...but seriously, put in a new set of injectors might solve your problems.

[2.5-12]

in all fairness, I did replace a lot in one go.. bad idea.

since replaced a lot more than that even. whew.

some day it'll run right, even if I have to convert it to Motronic 1.1 to do so.

[dnguyen1963]

Ahhh...but that is the life of an E30. Everything is running perfectly until you play with the engine. How many times have we heard..."but it was running perfectly until I replaced..."?

[2.5-12]

I am not convinced that you can visually inspect an injector. I have seen many that look normal, but will not spray or have abnormal spraying pattern. I have seen some with lagging fuel delivery, which can contribute to hydrolockings.

why does the engine behave properly under load if the injectors are shitting though? shouldn't that make it even more likely that they're working at least somewhat satisfactorily?

I'll buy a set from someone and rebuild them I guess, not a huge investment. or I suppose swap the entire rail from my daily to this car since that car runs as well as any ETA has ever run.

[dnguyen1963]

I am not convinced that you can visually inspect an injector. I have seen many that look normal, but will not spray or have abnormal spraying pattern. I have seen some with lagging fuel delivery, which can contribute to hydrolockings.

[2.5-12]

If you think you have hydrolocks then too much fuel is being dumped into the cylinders. Rebuild the injectors or buy a new set. Pintle caps and o-ring alone are not enough if your injectors are not spraying correctly.

I am aware of that, but usually when the injectors are worn to that point, they are visually damaged when you're in there to change out o rings.

[2.5-12]

both.

I have replaced every gasket and hose in there as well.

[SlamedIAm]

0 vacuum leaks since i just sealed everything.

Have you ran a smoke test to confirm this or are you assuming because you've replaced so many parts?

[dnguyen1963]

If you think you have hydrolocks then too much fuel is being dumped into the cylinders. Rebuild the injectors or buy a new set. Pintle caps and o-ring alone are not enough if your injectors are not spraying correctly.

[2.5-12]

Well, if you still get black soot then your car is still dumping way too much fuel into the system or you still have a big vacuum leak somewhere. What type of injectors do you have? I would remove the injectors then hook it up to a battery and check to make sure that fuel is being delivered correctly (google the procedure). I have seen injectors shooting straight stream of fuel without any spraying pattern.

standard ETA low impedance injectors. 0 vacuum leaks since i just sealed everything.

just replaced what I think was the DME temperature sender (orange new) old was clear.

occasionally when restarting after stalling, it does seem like it is hydrolocking on fuel temporarily but its hard to say.

I do somewhat suspect injectors but I just replaced pintle caps and o rings and everything looked good. but I did not test spray pattern (have been trying to avoid it). just seems odd that the car ran perfectly before all the maintenance stuff.

[dnguyen1963]

Well, if you still get black soot then your car is still dumping way too much fuel into the system or you still have a big vacuum leak somewhere. What type of injectors do you have? I would remove the injectors then hook it up to a battery and check to make sure that fuel is being delivered correctly (google the procedure). I have seen injectors shooting straight stream of fuel without any spraying pattern.

[2.5-12]

I pulled the injectors/fuel rail out and jumped the pump just to make sure they weren't seeping and everything checked out a-ok there too.

they don't leak.

anything else to check/do? there's practically nothing left on this car to change.

[2.5-12]

ok, skinny scoop guys

I got my 325i out of the shop and rolled this bad boy 325e in there.

decided 'fuck it' and just did all of the gaskets on the intake manifold, all of the hoses, new clamps etc.

while I was at it, I decided to eliminate the variable of the intake manifold, TPS and TB since the old manifold had a suspicious crack in a potentially problematic area.

started it up....

no change. still revs really nice. idles fine (but at about 900rpm) cold start injector plugged in or unplugged, makes no difference.

still getting wet black soot out of the exhaust when I rev it.

starting to run out of things to try short of converting this thing to Motronic 1.1 SETA electronics.

fuel pressure is 30PSI at idle and when off, rises to 37psi when revved which is right within spec.

[crazyman]

Cool, glad I could help.