I echo Dougs advice. I'm surprised your experiment worked. The drivers side is the master and the passengers the slave. Your lucky it ran at all, and didn't roach a computer ! Pop those covers off and check that wiring ! It's the simplest and most likely the cause. The clue for me is that it changes when it gets hot. Exactly what mine did with bad wiring. Don't waste another brain cell trying to figure it out without opening up those covers ! Rule out the obvious first. And perhaps the least expense !
Ive been chasing a "idle hunting" symptom on my 94 600SL, just to bring everyone up to datd, I have replaced all wiring harnesses, rebuilt the transmission, had the Throttle bodies rebuilt. Talked to the dealer service tech, he suggested I may be having trouble with the "tb's" again so sent them to "BBA" they returned them showing "no fault". I had no power, back firing, idle hunting (rpm's down to 100 catch & race to 1800, drop to 100 race etc.) I began to think about the EGR valve(exhaust gas recirculation valve) went on Utube thought it might be the problem. Diagnosed the problem with a brake bleeding vacuum pump found EGR to be holding vacuum but sticking. Took it out, cleaned it with carb cleaner and behold, it purrs like a kitten. Not bragging just lucky!!
Now, the problem I'm still left with is hesitation under acceleration. With the car in park if I push the accelerator down hard it will backfire. If I push it down slowly it will stumble then rev up just fine. Not the kind of performance I would expect out of the "uber" auto. Anyone got any thoughts? I would appreciate any input you may have
Good info ! Do you have a picture of the EGR .? I need to check mine just because. I have about a 50 rpm idle excursion on occasion. It is beyond subtle, but I'll bet that's where it is. Anyway, your backfire issue I'll bet is related to a lean condition. I haven't bird dogged that yet, but there is an enrichment valve somewhere in the system. Look that direction. I'll bet that's your problem.
Thanks, that's good input. The motor sounds like a car with a carburator when the accelerator pump has gone bad.
I will try to get a picture of the EGR valve and post if I can figure out how. The EGR is physically located under the Throttle Body on the exhaust manifold. There is a rubber vacuum hose that activates it. They fail closed if the vacuum diaphram which operates them breaks, but more often they get clogged with gunk from the exhaust and they stick. You can replace them for about $300 but in my case cleaning seems to have worked so far.
Where in the world would I find an enrichment valve? I have no idea where to begin to look. :surrender:
I have the 129 Star info, but it is crazy to use, and I have not found anything the references that device or problem. I'm sure somebody knows how the enrichment works at a idle to WOT throttle setting. As I did, you recognized the correlation to a bad accelerator pump on a carburated engine. We used to get those on Quadrajets or Holley's back in the day !
Completed rewire of ETA's a few days ago and took the car for a long drive yesterday. I'm happy to say that everything seems to be fine (NO ASR) and the car is running great. The rewire was tedious but not as bad as I expected. My thoughts: It helps to have experience in working on electronics. If you have never done any soldering/desoldering, think carefully before attempting. If you don't have a quality soldering station, get one before attempting this rewire. Weller and Hakko both make good units that maintain even temperature. I used a quality solder pump (sucker) and found that to be much more effective than solder wick. As everyone else has mentioned you should be very careful with documenting every wire thru pictures and drawings/notes. My wiring was so deteriorated, that in several cases, I had issues with identifing the original color (coating was gone).
Finally, a special thanks goes to Tracy for providing some one-on-one advice and encouragement. Also the imput from others on the site and Uber was invaluable.
Thanks to everyone and good luck on your projects.
I am selling my 1995 SL600 convertable with hard top 120K miles. Let me know if anyone interested. Inside was redone few years back. Car is in Sacramento, CA. Call/text 845-489-5199 if anyone interested. thx
So, with this free time that we all have in our hands I decided to take a look under the car and do some preventive maintenance. I've known since I got this car a year ago that there's surface rust but upon inspecting the o2 sensor two things came to mind. First is, what are my...
Hi there, I am looking for one or more of the retaining clips that hold the electric seat control switch into the door panel on my r129. I’m hoping someone out there can help me source one or more of these please?
See attached picture of reverse of switch. The clip in question is on the top left...
I'm back at it with my R129.
Car is running great, but when i started today, the CEL came on instantly. Scanned the modules and no codes at all.
This is the second time this has happen.
If i disconnect the battery, the battery goes away and wont come back for a couple of days. Comes on when...
Looked all old threads but where can i find pictures explaining how to adjust the transmission shift point between 2nd and 3rd when engine is cold. It is a feature on all r129 with catalytic converters so they heat up quicker and as such start working quicker.
Where can you adjust ? Where are...
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