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Misfire/stuttering/high idle - 95 W124 E200T

Splicer436

New Member
Joined
Jun 11, 2013
Messages
4
Car
W124 E200T, W123 200
Hello fellow MB owners,

currently chasing some quite annoying problems with my car.
1. The engine "stutters" at low RPMs (aprox around 1500ish), which makes it very unpleasant to drive, especially in the city. Seems to go away somewhat when applying full throttle on acceleration.
2. Starting off from a standstill (it's a manual), if I dont give it quite a bit of gas before, to get the revs going, I always feel like it's close to stalling. My W123 by comparison is waaay smoother (and easier!) to drive.
2. Cold starts are a problem, takes a few seconds to start and does so very rough, although once it starts the idle is quite stable, around 1000 (is that normal? this is my first W124..)
3. First hour of driving in cold mornings, idle stays at about 2000! Afterwards it drops to about 1000-1200, never lower. Also, it's not perfectly stable, you can always sense fluctuations, not enough to shake the car or anything like that, but still noticeable.
Also during summer time, the idle used to sit at around 750ish, with a much more noticeable flutter every couple of seconds. Not sure if the cause of the change is the temperature or just the worsening of whatever issue is causing this.
4. A couple of times, in lower than usual outside temps (about -15 C), the ABS light came on and stayed on for a while.

What I've already done:
1. wiring loom (ironically, didn't seem to change much, although it was in an appaling condition)
2. spark plugs, and their wires (dont know the correct term in English, sorry - coils I believe?)
3. had the intake cleaned (quite a bit of oily residue on the interior walls), again, dont know the correct term in English, I am reffering to the whole intake assembly sitting next to the engine. The small pipe leading from the intake to the ECU has quite a bit of residue in it as well, cleaned it out as advised by a mechanic, again no change.

What I think I should try next:
1. OVP relay, the ABS light coming on lead me to this option. The unit corrently in the car is a single fuse one, code is 2015403845, I assume the previous owner got a used one from a W201? I've put up a different thread asking for the correct code, before ordering a new one. http://www.mbclub.co.uk/forums/elec...ovp-relay-code-95-w124-e200t.html#post1862663

2. the crankcase breathing/ventilation system, hopefully I got the name right. I've read on different forums that the clogging up of the ventilation valves belowe the intake could lead to oil + condensation in the intake and in the pipe leading to the ECU, and therefore causing problems to the MAF sensor which is located somewhere near the ECU unit.
Of course, I can only assume I haven't got all my facts right, this is all supposition based on what I've read online.

Anyway, ANY insight would be highly appreciated, I appologize for the long post and thank you very much for your time. Cheers!
 
Thank you grober, I will be taking a closer look at my current OVP.

Also, I forgot to mention, while the car was in the shop for the loom replacement, the mechanic briefly installed a throttle body & PMS unit from another car, there was NO difference!
Hence my current suspicions regarding the OVP/crankcase breathing system.

EDIT: for some reason, I cant edit the OP. Earlier I was referring to the throttle body (not the intake) having oily deposits on the inside walls, as well as the small pipe that leads from the throttle body to the ECU unit.
 
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If you have the PMS ecu [ USES MANIFOLD PRESSURE] then you wont have a MAF [ HFM ecu] Make sure the entire vacuum path from throttle body to ECU is clear. Might try washing out the ECU inlet pipe for example.
 

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