I've looked for codes on the 38 pin connector on socket 4,6,8,14,17,19,30
On socket 17, I got a code 8....Trans Overload switch
On socket 6, I got code 32....CAN data to left/right igntion module.
This seemed the most promising as it has to do with the ASR, which this car has.
No code for the 02 sensor but when it was on the scanner it seemed to be working OK. (I had a MT2500 SnapOn)
So, here is what happens.
Get into a cold car and it starts right up and purrrs.
Drive to the hiway ramp, 3 miles stop'n go, purfect...no problems.
Get upto hiway speed and it is flawless. Lottsa power, USUALLY no issues.
Once, however, when I floored it to pass it did start to miss but then seemed to settle down, until I got off.
After driving about 10 miles at hiway speed and getting off it may start to miss with rough idle as I come to the stop sign just after exiting...BUT NOT ALWAYS.
Usually it will idle fine. I stop in at a small shop within 1/2 mile of exiting the hiway.
Get out and shut the car off, remember it is still running fine at this point, usually.
I return to the car after 15 minutes and as soon as it starts it misses, rough idle, shakes..like it is running on 4 cylinders.
I can drive the car, takes awhile to get it upto speed, but it will get moving.
It is NOT in Limp Home Mode.
Sometimes, as the RPM increases it will suddenly surge ahead as if it wants to run normally, but it will revert to missing as I backoff on the gas.
If I apply to much gas while it is missing it will back fire, regardless of RPM.
So, I can limp back onto the hiway, slowly getting upto hiway speed, backfiring all the way.
It will run upto 60/70 MPH eventually, not that long.
And then...mysteriously, it will start to run OK again, sometimes, but not always.
As I exit the hiway after running at 60 for 15 minutes it MAY be just fine....no misses or rough idles.
But it could also be acting up.
In this case, and driving through town, I have to keep the RPM up with the gear selector to get it moving.
Again, this is the weird part, if I run it this way with high RPM (2000/3000 in 1st/ 2nd) it is just as likely to loose the miss and run normally again.....and stay that way for the rest of the 5 mile drive home.
Now tell me that isn't frustrating.
I have a friend with a 400E so I have swapped all the modules incl. ignition, temp sensors, cam sensor, replaced the CPS and swapped coils. Replaced coil wires and completed inspected both caps/rotors/spark guard for streaks.
One is almost new and the other is fine.
Test everything with high voltage.
All the vacuum lines are good or new.
Replaced the ETA and it has the new upper engine harness.
Plugs are fine...tested each one seperately.
Obviously it is something getting hot.....but what's left to check?
And it doesn't do it consistently the same way all the time.
None of the codes suggest ignition OR fuel problems...so what ever it is, it ISN'T throwing a code. A clue???
The wires on these engines (all mid 90's Mercedes...unbelievable) are soooo bad it could be anyone of the other harnesses.
But if that was the case then I wouldn't be the only one with this weird problem....I don't think.
I've spent hours on the forums reading and did find a similiar problem with a 92 SL500(same engine M119)....lots of talking back and forth....but no answer....the forum just ended. 2 years ago.
Geeez....that doesn't help when solutions aren't posted.
Jim Forgione suggests that the fuel pressure reg. should be changed...which I will do...but I doubt that is it....but then who knows. Jim does seem to know his stuff.
Thanks for your combined brain power boys, I do appreciate it.
Someone MUST have run into this and fixed it.......hope the symptoms help jog the 'ol grey cells.