400E raw fuel goes in cat, no power - PeachParts Mercedes-Benz Forum

bgalakazam · #1 02-10-2013, 07:36 PM

Hello all! I have been posting on 2 other forums about this, but I have been a long time peachparts lurker. I wanted to get your opinion on this case.

old thread 1, old thread 2

Problem: All the fuel doesn't burn in the engine and burns in the catalytic converter. Because of this car cannot be driven a long time as it will catch fire again.

Before that there was a fire. Many things were exchanged, including the O2 sensor, lower wiring harness (124 540 3130), plugs, ETA with rebuilt and certified one. The car has no power and the engine shakes. Car is driveable on freeway and city, just slow acceleration due to limp mode. Catalytic converter goes red after just 10-15 min.

It looks like my wiring harness has been changed, but I don't know if it went bad. I threw in already more for repairs than I paid for the car, so I don't want to spend any more money on anything uncertain of fixing the car. There is dealer computer diagnostic for $180, but as of the ETA change, I was able to clear all the pin codes and they didn't come back. And I am afraid they can't test the actual harness?

This is the sticker on the cable, does it give any info whether the changed one is bio-degradeable as well?

DELPHI
Werk Jelesnia
F. D.: 06.10.04
Pers. Nr: 37

MB 124 440 1906
Z.D. 09.09.92

Also, since the ETA is tested and sure to not cause problems (and no fault codes), the Mass Airflow Sensor is the other guy that may cause problems. But there are no more codes.

Any further suggestions or info will also be appreciated.

Cheers!

professor · #2 02-10-2013, 08:57 PM

Unburnt fuel! Could it be that you have no spark at some cylinder?
The car must have less power than what it should.

bgalakazam · #3 02-10-2013, 09:41 PM

Car feel like 100hp (slightly faster than my 240D). The spark plugs are new. The cables are in good condition, the ignition coils and rotor caps can be better, but car was running fine before that. Some suggest it may be ignition/timing issue. Other point to the harness/eta/maf for the cause. I don't know if the $180 dealer diagnostic will show anything since there are no longer codes since new eta was installed (and before that they couldn't be cleared). Car shakes when idle and running and the RPM have a delay in going up. Car really feels like a 3-4 cylinder instead of 8. Fuel pumps and filters are good.

Hirnbeiss · #4 02-11-2013, 07:11 AM

Are all the plugs wet with fuel?

timmyr · #5 02-11-2013, 07:13 AM

hello,

looks like the harness has been replaced. FD =fabrication date ; zd= design date. for more info check out this threAD: 94 E320 Delphi Harness. 2 dates? how do I know if I have an updated harness?

EDIT: since i've been on the forum , i've never heard of the new updated harness having biodegradable wire insulation. your updated harness should be ok as long as it was not physically damaged(fire, etc).

have you ruled out your fuel pressure regulator? if faulty, it will cause fuel to leak into the intake manifold. this could possibly explain the glowing catalytic converter.

did u take the car to a dealer for diagnostics?

have u built the code reader? if not, see thread, specifically post#11:Reading Codes

good luck

bgalakazam · #6 02-11-2013, 08:08 PM

I have tried the codes. With the old ETA I couldn't clear them. I replaced with a rebuilt one by BBA and was able to clear the codes on pins 4, 7, 8. Pins 17 and 19 had no errors. Took car for 15 min drive, cat went red again so I stopped. None of the codes had come back.

I don't know if the $175 dealer computer diagnostic is worth it, unless there are more hidden codes that I can't see.

The plugs are OK. There is no smell of raw fuel in the engine, only at the exhaust.

There is loss of power. The car feels like < 100hp, but it's driveable. The RPM stay higher, due to this (e.g. 2100 at 65mph as opposed to about 1500 before).

I could care less about the power, but the raw fuel will cause the cat to heat up a lot again and cause another fire. The car is not drivable. Not to mention it will not pass next smog check and I won't be able to renew the registration.

tecqboy · #7 02-11-2013, 09:26 PM

Does this vehicle have an EGR valve?

David Hendy · #8 02-11-2013, 10:14 PM

I have an lh module and e gas (controls the eta) module I can send for you use to test.

Thats where I would look, given all that you have replaced.

Just pay shipping both ways

mbdoc · #9 02-12-2013, 08:30 AM

Has the transmission been OUT?? if so possibly the ring gear has been installed incorrectly.

A timing light can show if that is the problem.

bgalakazam · #10 02-22-2013, 03:08 PM

Problem solved. It was the far ignition coil. It was the original one form 1993 and had given out. Dealer found this right away... all the 1000's spend on indy mechanics... anyway

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