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W124 E200 M111.940

18K views 41 replies 8 participants last post by  Urms  
#1 · (Edited)
Hi everyone

My cars RPM will drop when i turn the AC on, or when I turn the steering wheel completely to 1 side or the other.

If I steer completely to either side while the AC is on, the car will 100% stall.
It rarely stalls while the AC is on and the car is idling in Drive with my foot on brakes, also rarely stalls when turning the steering wheel with AC off.
Car idles at about 900 rpm at park, going into reverse or drive will drop to 400-500rpm .
This issue has survived 3 engine swaps and has been ingoing for ~8 years.

No idea what's causing this, any help will be appreciated. Thanks in advance :)

Edit: video of the issue:
Edit2: Title correction E200




2695736
 
#22 ·
That would have been very helpful to know back in post #1.

Anything else you'd like to disclose and come clean about??? Now would be a great time.

Knowing what we know now, forget about checking&testing volts. You need to go after the Amps. Pull the fuse to each circuit, and check the draw with engine off, key out. Anything over 50 milliAmp is bad.

I don't know how you managed to live with this for over 8 years ago, but obviously it is not high enough on your priority list to warrant resolution back then.
 
#23 ·
That would have been very helpful to know back in post #1.

Anything else you'd like to disclose and come clean about??? Now would be a great time.

Knowing what we know now, forget about checking&testing volts. You need to go after the Amps. Pull the fuse to each circuit, and check the draw with engine off, key out. Anything over 50 milliAmp is bad.

How you managed to live with this for over 8 years ago, but obviously it is not high enough on your priority to warrant resolution back then.
Ah man, my bad, I apologise, really.
I've had the car for 14years, on the past 8 years it's been driven like 20k km. I've had multiple other cars.

I'll be updating the post, thank you for your input, really appreciate it.
 
#24 ·
One more thing, based from your video the car is not doing its cold start enrichment (i.e. raised rpms) properly.

I know it has already been mentioned, but what about OVP, engine wiring harnesses, throttle body, and PCM??? Ditto on intake temp sensor, coolant temp sensor, etc, etc, etc.

And what is the story for having swapped the engine 3 times??? These engines are virtually bulletproof outside of pouring sand into it.

We really need to know the WHOLE story from A-Z before going further.
 
#25 · (Edited)
The original 2.0 would overheat(Head gasket I think), I only had an 1.8 at that time so i slapped it in, but it was powerless so i swapped for a 2.0, it wasn't in the optimal condition so i planned on swapping as soon as I found a better one. Now it has a better 2.0.

OVP- Swapped, working
Engine wiring harness- Remade from scratch.
Throttle body- swapped, working.
 
#26 ·
Throttle body was swapped" from what? And what is the build date on it?

Sounds like you want more power, in which case why even bother with these lawnmower 4 cylinder engines???

124 performance begins with 6 cylinders, and 8 cylinders is where it's at.
 
#30 · (Edited)
Where did I say to start looking for another throttle body??? Try a brand new gasket from your local MB dealer first, or Elring as a backup source. See if that makes any change to help stabilize the idle. Since you didn't change gaskets, your car is almost guaranteed to be sucking in false air and throwing off the MAF and other sensors among other things.

No Febi or other junk. I know Albania is Febi's #1 market, but Febi is not a OE supplier. At least not for the W124.

And clean off all old gasket material before installing the new one.

Question. If it is more power you wanted, why didn't you just find a 6 cylinder or better yet a 8 cylinder???
 
#31 ·
When I say i installed a new engine, that includes throttle body,gaskets, etc. So in total It has been swapped 3 times. Now there's only 1 time where the car was running normally, I swapped this "packet", but after some time it went back to normal. (Check picture below)
I agree, febi is bad,we go at a junkyard instead of buying febi.

Answer to your question : the 1.8 couldn't even go up the hill with 17inch wheels.

2695786
 
#34 ·
You're just gonna wear out another engine. MB does not offer LPG in any of its cars for a good reason. Their engines do not take to LPG.

If you want LPG, get a full size US truck with a V8 like a Ford F150 or a (DODGE) RAM. Those do take to LPG extremely well. Ditto on some (but not all) Japanese cars.
 
#35 ·
I don't really care about this engine, i have another M111 2.2 standing by. It's just that I wanna fix this issue before I put it on. And it survived 3 engine swaps so it's definitely not an engine issue? Unless the M111 is plagued by these issues but I doubt it because some of you would've heard about it.
 
#36 ·
You've had this issue for over 8 years, so why fix it now?

Your issue(s) sound electrical in nature (PCM could have gotten damaged due to eco junk, self made harness is a no go in my book, throttle body is unknown) BUT the mechanical age of the car is working against you. However, based on the new amount of info which you've now reluctantly given out it's anybody's guess.

If it was my choice, I'd do the Elvis thing and shoot the damn thing in the fender and let it be someone else's problem. After all, it's only a 4 cylinder and it's never going to be worth more than a couple of six packs of beer.

Then you can have your performance when you find a 6 or 8 cylinder car. The M104 is a great engine (except for the KE-Jetronic 104.980) and is way more refined than any of of the 4 cylinder versions.
 
#37 ·
I don't even remember, it's probably been going for more than that, it's just that it's been parked in the garage until 2 months ago.

I've been looking for a 3.2 M104 for more than 4 years... It's just really rare.
I'm missing an ECU for the 2.2L engine(also really rare?).
Anything bigger than 2.0 is rare here(petrol/gas).
Found a 3.2 from a W140 with a missing ECU.
 
#38 ·
Since you've swapped engines multiple times with multiple types but you don't have the matching PCM means we're straying even further off the mark.

This puzzle is getting only harder to solve. So which PCM is currently in the car???

Anything else we're missing that we need to know??? And please, do not hold back anything. I'm about at the end of my rope since I like helping people repair their cars or motorcycles. Unfortunately, I don't repair cars that have been botched to the point of "life's too short to deal with this".
 
#40 · (Edited)
I'm not too familiar with the M111, but it should have a load compensation system which automatically maintains the correct idle speed if the A/C is switched on, PS activated, selecting a gear (Auto) or lights etc. switched on (current draw lowering the idle speed). This may be part of the ECU, or a separate solenoid/relay/switch. I would focus on that if I were you.

Edit: Found this on another post: "diagnosis/working:- theres a small motor inside the actuator, this is what regulates the idling and controls the throttle when engine is on load (AC, steering, engaging gear etc) the ECU senses these changes as load on the engine and sends current to the motor inside the actuator, this in turn increases or compensates for the load/drag." - credit goes to kuntash

Also check this post: Idle dips when a/c is turned on
 
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#41 ·
I think you might consider to unplug your throttle body cable harness and try to simulate the trouble u come upon.
This way can help u isolate some of the idle problem.
M111 Engines in W124 chassis can be started and run quite well even with a unconnected ISA.

Besides, the throttle body has a recirculation hose connector port, adding more air (from gas tank) into intake for engine to burn.
Lacking this extra air at idle, you might have weird behavior of the engine, since you opted for a LPG. And besides, do you seal the connector?

Another similar scenario I ever met would be a worn pulley of the AC compressor, a worn guide pulley of the tensioner, and also its biting belt absorber/damper. You could remove all these pulleys and immerse them into ATF for a while and mount them back, then test. This method could lubricate the internal bearings on the pulleys for diagnosis purpose. If it works, then you find your problems and change them accordingly.

In some rare cases I met before, I changed the AC compressor RELAY mounted right after the battery. This 4-cylinder clima relay controls AC on/off and also gives signal to your ECU (HFM for sure, but PMS I don't know). If it fails, your AC compressor won't behave normally.

Hope you find your problem soon.
 
#42 · (Edited)
I have the same engine in my '95 coupe. Had exact same problems - engine dying as additional load is introduced / cold engine correction not there (had to hold the pedal while engine warms up). In my case electronic throttle loom (from TB to connector) had eco junk harness that was cracked to hell. After a diy rebuild the problem went away.

You can inspect if this is the case with you by removing the throttle and opening it up. The wires including their insulation can be seen connected to the PCB inside the TB. If you see cracks on the insulation, that 90% is the cause of your problem. Give it to someone who has hands growing from the right place to replace the wires (the connector is the most difficult part, otherwise its a breeze).

On another thought, the motor which adjusts the compensation can go out aswell, but its not that difficult to test it once the TB is opened up.

edit: Link to my thread where apart from other things i was solving my ETA problem: