240D is sick! - PeachParts Mercedes-Benz Forum

240Demon · #1 10-15-2003, 07:10 PM

Ok, I have yet another, and more pressing issue with my 83 240D.

The car started running rather peculiarly today...here's what its doing...

1) the car idles at a very low RPM and the motor shakes a lot, and the idle speed decreases as it sits longer at idle
2) it smokes a lot, and the smoke does not smell like normal diesel exhaust
3) it has good power when driven, but immediately starts running bad when it goes back to idle.

I have no idea whats going on...can someone enlighten me??

Thanks

Wasuchi · #2 10-15-2003, 07:39 PM

Sounds like your idle is set too low (something must have slipped), I'm not sure how to adjust it on your car though. Might try a search for "idle adjustment" or something similar. Not sure what is causing the smoke however....

#3 10-15-2003, 07:41 PM

the speedometer...an idle adjustment...one advantage the 240 has over "bigger" cars. See if there's any difference.

#4 10-15-2003, 07:43 PM

Maybe the fuel filter in the tank?

psfred · #5 10-15-2003, 07:47 PM

Clogged fuel filters comes to mind, but what does the smoke look like? If it were older, I'd say you have a vac pump problem, but by 83 the vac pump exhausts into the crankcase and you cannot blow oil into the intake anymore.

I'd also check the EGR valve to make sure it isn't sticking open -- this will cause serious black smoke, a funny muffled rattling, and poor power until you get the engine revs up. My Volvo used to black out whole lanes of traffic before I disconnected it.

Peter

240Demon · #6 10-15-2003, 10:55 PM

well, I showed the car to my MB Dealer Tech buddy, and he said the car dropped a cylinder...so...I guess I will be putting a motor in the car...

Damn!

kerry · #7 10-15-2003, 11:00 PM

What does he mean by 'dropped a cylinder' and how did he diagnose it?

240Demon · #8 10-16-2003, 12:28 AM

well...he heard the whooping sound in the tailpipe and smelled the unburned diesel. He has been at it for 20 years and I trust him, and when i got home i cracked the injectors and found that #1 is dead.

leathermang · #9 10-16-2003, 08:21 AM

Dropping a cylinder.... UNLESS YOU MEAN IT DROPPED ONTO THE GROUND....
Only means a cylinder is not producing power...
which could easily mean , on a diesel, that something was wrong with the injector...
So a Little more investigation is in order... before rebuilding the entire engine....

What change happened when you ' cracked the number one line' ?

I assume you mean that ' no change' happened.... because this is how you would test to see if a particular cylinder was ' underperforming'...

kerry · #10 10-16-2003, 09:06 AM

I agree with Leathermang. If the diagnosis is that a cylinder is not firing, you need to find out why before jumping to the conclusion that the whole engine needs to be rebuilt. It could be a valve problem, a ring problem, a piston problem or an injector problem.

Toblin · #11 10-16-2003, 01:42 PM

If one cylinder was not firing at all I would think it would be noticable under load as well. I'd pull the injector on the cylinder in question and get that puppy tested.

Rick Miley · #12 10-16-2003, 03:12 PM

Quote:

Originally posted by 240Demon
3) it has good power when driven, but immediately starts running bad when it goes back to idle.

Sounds to me like it is only misfiring at idle. By any chance, did this mechanic friend offer to buy it from you cheap?

240Demon · #13 10-16-2003, 06:52 PM

Man, some of you guys are such schmucks!

"By any chance, did this mechanic friend offer to buy it from you cheap?"

I am offended by that, the guy I was talking about is a good friend who happens to be an MB mechanic.

He is bringing me the tools to do a compression test today. I would prefer it be an injector, as I really don't wanna do a motor swap right now.

yes, when I cracked the injector, nothing happened, which, in my experience means no action in that cylinder.

I really hope that its an injector. I checked the valves and they are all in order, so its either and injector or bad rings.

If its a bad bottom end, I am gonna put a junkyard motor in it, as i found one with a 90 day warranty for $600 in Eugene.

So, anyway, I hope it all turns out well, thanks for the advice guys. I will keep you all updated

psfred · #14 10-16-2003, 08:35 PM

I hope it's only the injector too! A compression check will help (good compression, it has to be the IP or the injector), but if you don't have good compression, you will have to investigate further.

A sudden loss of power with no terrible clanks and bangs could easily be an injector or IP seal ring, especially if you get funny smoke (hite, blue, black???), and you get more or less normal performace at speed -- an injector stuck open will cause all sorts of funny running and smoke, as the fuel is injected way to early and at low pressure.

Good luck!

Peter

Rick Miley · #15 10-16-2003, 09:52 PM

Sorry, Nick. That was meant to be in good fun, but I know fun is hard to come by when you're facing an engine problem. Best of luck with it.