S.O.S! 95 E300 diesel, ECM? - PeachParts Mercedes-Benz Forum

stcbenz83 · #1 02-06-2012, 06:22 PM

So my E300 has basically fallen apart this past week. I'll have to explain more later but, the "latest' is: when I was backing up to my garage. The pre-glow warning buzzer started sounding but, really high and off pitch. Next thing I know the engine REVVED itself up to over 1000K!!!!! WTF?? Made sure nothing was caught as I repeatedly pressed the accelerator. It would always fall back to above 1000K-1200K, SHut it down, restarted and it was idling like usual.. Why would it do this? I was under the assumption that there is no computer onboard with the 95 (why I bought it) and that it was all mechanical linkage?

Ontop of the rear end that just decided to fall apart (replacing sub frame mounts this weekend) and a load of other stuff.

Anyways, any thoughts? suggestions? where to start?>?? would be super helpfulll

Thanks!

sixto · #2 02-06-2012, 08:33 PM

You was duped! The E300 has an ECU to control at idle, emissions and possibly the variable geometry intake manifold. Knocking out the ECU won't strand you but the idle might be unstable. I'm not familiar with the 606.910 but I check the OVP relay and voltage regulator when electricals behave strangely.

Sixto
87 300D

engatwork · #3 02-06-2012, 08:53 PM

Make sure it is not the throttle linkage sticking causing the idle issue. How many miles are on the car? Has the engine wiring harness been changed?

sixto · #4 02-06-2012, 08:54 PM

FWIW, that's a seat belt warning buzzer. There isn't a preglow warning buzzer.

Sixto
87 300D

spark3542 · #5 02-06-2012, 09:13 PM

1000k??? That's 1 million rpm! I'm surprised the valves weren't floating!!

sixto · #6 02-06-2012, 09:19 PM

Maybe that's EGT in Kelvin. Valves would float and melt.

Sixto
87 300D

stcbenz83 · #7 02-06-2012, 10:24 PM

Sorry for the typo's all. I was in between getting off my 11 hour work day and, grabbing all my books for my night class. Also, this latest issue is the 'icing on the cake' with a list of expensive and very time consuming (suspensions falling apart). This past weekend, my rear sub frame bushing i believe broke (waiting on bushing to rule that out) as I'm now getting a horrible bang/clunk sound which, would be similar to the sound of when the rear shock bushing or whatever, fails and is going in and out of the trunk...only that's not the problem.

Anyway, I had my bearings replaced (don't have time) and, the guy broke teeth off the ABS speed ring on both hubs.. which, the cheapest Hub i've found are $210, i think from Pelican. x2= $420 and, no abs (been having a lot of black ice in the mornings here as the temp is starting to drop).

Since then, I've now noticed the if I turn the wheel to the right, the DS front tire sounds like it's braking? and stops the car.. Which, I now need to investigate what went on when the bearings were replaced and why my DS is braking (low, parking lot speeds)

Also, my SRS light keeps coming on and, my stereo keeps dying when the light comes on. Light goes off and stereo back on. It's not a "check" of the airbag system from driving an extended period as it will do it randomly and at times, will do it 2,3 or 4 times before I hit the steering wheel which oddly, cures the problem

BTW: before this happened, The stereo was going off, whenever i'd press my drivers window switch up(windows fully closed to begin with) . I noticed that when I did this, a really odd and hard to describe noise was comming from the window lift... electrical sounding is the best I can do and no, not the usual noise they make when they are already closed and press the up button. Anyway so I did this a few times and that's when the SEAT BELT BUZZER started sounding only demented and way higher in tone. Once the buzzer went off, it gunned itself!!! I had my foot hovering and slammed them in time to avoid going through my garage door.

Today, it started running like crap and missing with a bunch of smoke. After I drove back to my other job, it was running fine so, Luckily my dealership actually had 3 meter's of the injector return lines instock! Just need to find the time as im positive that's the culprit.

Anyway, there are probably 2 or 3 more issues I'm missing but, that would be the reason for my initial, crapily posted thread

Yes, Im aware there isn't a "pre-glow" buzzer but, being in a rush and at the time, I wrote down what came to mind first. Same with the RPM numbers and anything else that's semi off so, SORRY!

Not the throttle linkage as A: i didn't have my foot on the pedal and was slowly backing and getting ready to stop and B: I punch the pedal a bunch and, it would return to 1K. I shut it down, restarted and it was back to its normal Idle.

spark3542 · #8 02-07-2012, 10:54 AM

2 thoughts on approaching this come to mind (from a high level):

1) In general, things break one-at-a-time. One root cause may create several different symptoms, leading one to believe there are several different problems, when in fact one solution may solve all of them.

2) In general, truly bizarro electrical behavior (meaning window switch affecting radio, for example) is usually grounding problems. This may be expanded to voltage regulator or computer control problems, but one key missing or weak ground connection can have electricity taking all sorts of weird pathes.

When I'm deep in the weeds thinking a problem is super-complicated, I stop, step back and remind myself that there's got to be a simpler solution than what I'm thinking.

chazola · #9 02-07-2012, 11:42 AM

The ELR relay that controls the idle is back with the ovp behind the battery, but it has no obvious replacement parts like the fuse on the ovp. I don't think these are well-known for going bad though. Wiring harness/loose connections will also give you symptoms, if you're taking off the cross-over pipe to do the return lines, check all the bits of the wiring harness you can see, plus check and lube your linkages/ball joints.

I often find when I'm fixing one problem on this car I find another/the solution to an earlier problem that had me scratching my head. In the last week I've had my vacuum pump fail, a glow plug fail and injector return lines leaking like a sieve, all of course as the weather has dropped below freezing...

stcbenz83 · #10 02-08-2012, 06:05 PM

Quote:

Originally Posted by chazola

The ELR relay that controls the idle is back with the ovp behind the battery, but it has no obvious replacement parts like the fuse on the ovp. I don't think these are well-known for going bad though. Wiring harness/loose connections will also give you symptoms, if you're taking off the cross-over pipe to do the return lines, check all the bits of the wiring harness you can see, plus check and lube your linkages/ball joints.

I often find when I'm fixing one problem on this car I find another/the solution to an earlier problem that had me scratching my head. In the last week I've had my vacuum pump fail, a glow plug fail and injector return lines leaking like a sieve, all of course as the weather has dropped below freezing...

Yea, strange right? All these problems happened as the temp started to drop.. Some of the issues subsided but, am assuming they might or will come back. The electrical issue In regards to the noise I was hearing, I held the switch down and the noise goes down in pitch as the engine slow's down. So Since I can "Hear" the RPM of the engine, would that point me more closley to the alternator /voltage reg? or is it still about hunting down loose ground?? I mean it's some kinda loose grounding but, wasn't sure if me noticing the noise fluctuation with engine speed would point me any closer / to the alternator.

chazola · #11 02-09-2012, 03:26 AM

With the electrical issues you're having it does sound like it could be the voltage regulator if it's not a grounding problem somewhere. Bit of a pain to check/change on this car (what a surprise!) as you have to take the alternator off... luckily just slacken the belt and 2 bolts. Probably a good idea just to change it out anyway at your mileage, though mine was still good at 210k when I had to change my alternator. I carry a spare just in case as the regulator died on my old 300e and left me stuck once.

Have you tested the alternator output to see if you're getting a steady healthy charge?

connerm · #12 02-09-2012, 06:25 AM

Quote:

Originally Posted by chazola

With the electrical issues you're having it does sound like it could be the voltage regulator if it's not a grounding problem somewhere. Bit of a pain to check/change on this car (what a surprise!) as you have to take the alternator off... luckily just slacken the belt and 2 bolts.

I changed the voltage regulator on my 95 e300d a month ago with the car on ramps, and the sound encapsulation panels removed, and it was at the most a 10 minute job. Phillips screwdriver and two nut drivers. I didn't have to remove the alternator.

chazola · #13 02-09-2012, 08:02 AM

^^^On my car the heat exchanger pipes were in the way, so I couldn't get to the 3rd screw for the plastic back cover to take it off with the alternator in situ- like you say it should be a quick job but that one screw meant I would have had to take out one of the mounting bolts to check, in the end I replaced the whole alternator anyway as my pulley bearings were going bad.

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