Low revs hesitation om651

[Liam7755]

Been having a strange issue with my 2011 om651 .. so when I got it there was an EML light present which multiple scanning showed was the charge air intake temperature sensor .. on the intercooler pipe! The car ran FINE .. just with that EML light and arguably a little lower MPG than anticipated! I went to the car shop and ordered a new one .. £18 later the EML light vanished and I thought it was fixed up until the next morning when I started it the car would just hesitate and stutter in gear 1 and gear 2! It gets better once it’s up to temperature but it also now smokes a little dark grey/black .. and a very weird thing also occurs .. when I blip the throttle and let off, the turbo seems to spool up again as if I’m on boost!! Any ideas?

 

[Tonygw]

I am only guessing here, but it could be a split boost pipe. Or an air leak somewhere. You can get a smoke test done that will either show up any air leaks, split pipes or eliminate that from a possible cause. Cheap enough to do.

 

[alecmascot]

Been having a strange issue with my 2011 om651 .. so when I got it there was an EML light present which multiple scanning showed was the charge air intake temperature sensor .. on the intercooler pipe! The car ran FINE .. just with that EML light and arguably a little lower MPG than anticipated! I went to the car shop and ordered a new one .. £18 later the EML light vanished and I thought it was fixed up until the next morning when I started it the car would just hesitate and stutter in gear 1 and gear 2! It gets better once it’s up to temperature but it also now smokes a little dark grey/black .. and a very weird thing also occurs .. when I blip the throttle and let off, the turbo seems to spool up again as if I’m on boost!! Any ideas?

Is that an MB Sensor ?
You could have swapped one symptom for another.

 

[Liam7755]

I am only guessing here, but it could be a split boost pipe. Or an air leak somewhere. You can get a smoke test done that will either show up any air leaks, split pipes or eliminate that from a possible cause. Cheap enough to do.

Well, I’m suspecting one of 3 things is causing it. The MAF itself is not telling the ecu the correct air reading and the ratio is off (faulty maf), or it’s an injector going down (as im certain I have the old magnetic style Delphi ones that were recalled?) and finally, could it just be the egr valve even? I did take off the egr transfer pipe and that wasn’t bad at all really!

 

[Liam7755]

Is that an MB Sensor ?
You could have swapped one symptom for another.

Yes .. the first one I put in was not mercedes. It was from GSF parts but it was registered for my engine! So I went and got a gen mercedes one from my local mercedes garage and that made zero difference! I’m thinking maybe an injector is playing up .. or the MAF is on its way out. I don’t get why the MAF would seemingly work ok and let the car run if the IAT sensor is unplugged though??