Hi guys I turn to you again for guidance. I have a 2007 3.0si e86 coupe 6spd, 130k. My issue is When I start it up the idle is rough & now my service engine light is on. I’m getting codes p0102 & p1124. Mass or volume air flow circuit low input & differential pressure sensor intake manifold offset bank 1. A little history I just replaced the valve cover cause I was getting a lot of oil in the intake manifold. I replaced the disas both, cleaned out the intake manifold since it had oil in there. I replaced the MAF sensor already & Differential air sensor (MAP) sensor. Ran sea foam through it as well to get it really cleaned out. It has new starter, plugs, coils, vanos solenoids, thermostat, water pump. I thought once I cleaned out the intake manifold & put a new MAP sensor the idle would be fixed but doesn’t seem to be the case. I’m thinking a vacuum leak somewhere but I’ve been looking & checking everything but no good. It’s not my Maf sensor checked that & it’s not my map sensor it’s brand new.a smoke machine next step ya think? .any other ideas would be appreciated!
Rough Idle, Need Help!
- Thread starter Heebs84
- Start date
1) Get a vaccum test done for sure
2) My Eccentric Shaft Sensor (in addition to the above that you mentioned, DISA and CCV) ALSO needed replacing and caused my idle to bump around
3) Unfortunately you have to remove the valve cover to do the ESS which you might have already skipped past :/
4) I've heard (and believe) that the BMW OE gaskets for the valve cover, valvetronic motor, and eccentric shaft sensor are high quality and different than any third-party vendor (Rein, Febi, etc) and the third-party ones leak (leading you back to square one)
5) Also replace the VANOS check valves which filter oil to the VANOS solenoids, they can get clogged
2) My Eccentric Shaft Sensor (in addition to the above that you mentioned, DISA and CCV) ALSO needed replacing and caused my idle to bump around
3) Unfortunately you have to remove the valve cover to do the ESS which you might have already skipped past :/
4) I've heard (and believe) that the BMW OE gaskets for the valve cover, valvetronic motor, and eccentric shaft sensor are high quality and different than any third-party vendor (Rein, Febi, etc) and the third-party ones leak (leading you back to square one)
5) Also replace the VANOS check valves which filter oil to the VANOS solenoids, they can get clogged
Thanks for the advice, I actually did replace the eccentric shaft sensor, figured I’d do it before I changed the valve cover.
The thing about this idle problem is that I believe it had it before I bought it. I purchased it September of 2022. After putting headers & different exhaust on it and a tune I think it was a bit more noticeable. So the idle problem isn’t from anything I’ve done recently. The idle has gotten better actually & after the valve cover replacement. I just figured the oil in the plenum was affecting my sensors which affect the amount of air & gas to the cylinder. It’s been a very frustrating problem. I don’t mind replacing the parts since they probably needed it since the car is 16 yrs old.
I’ll look into the check valves though, my goal is to get the car running 110%. It’s running pretty good right now except the idle.
The thing about this idle problem is that I believe it had it before I bought it. I purchased it September of 2022. After putting headers & different exhaust on it and a tune I think it was a bit more noticeable. So the idle problem isn’t from anything I’ve done recently. The idle has gotten better actually & after the valve cover replacement. I just figured the oil in the plenum was affecting my sensors which affect the amount of air & gas to the cylinder. It’s been a very frustrating problem. I don’t mind replacing the parts since they probably needed it since the car is 16 yrs old.
I’ll look into the check valves though, my goal is to get the car running 110%. It’s running pretty good right now except the idle.
OK, sounds like you've almost got all bases covered. Do you notice your idle gets smoother if you push the clutch in? The dual-mass fly wheel might be going out.
On mine I think the DMF is an issue after driving for about 20-30 mins, if I come to a stop I can hear sort of a "rattle" and I feel a vibration in the stick. If I push the clutch in, the vibration and noise go away.
Since the fly-wheel is attached to the crank, if the rubber is going, maybe the engine is trying to compensate for the off balance mass but can't do it.
Also, did you check the 'smoothness' values of the cylinders in INPA?
On mine I think the DMF is an issue after driving for about 20-30 mins, if I come to a stop I can hear sort of a "rattle" and I feel a vibration in the stick. If I push the clutch in, the vibration and noise go away.
Since the fly-wheel is attached to the crank, if the rubber is going, maybe the engine is trying to compensate for the off balance mass but can't do it.
Also, did you check the 'smoothness' values of the cylinders in INPA?
Thanks for the advice, I actually did replace the eccentric shaft sensor, figured I’d do it before I changed the valve cover.
The thing about this idle problem is that I believe it had it before I bought it. I purchased it September of 2022. After putting headers & different exhaust on it and a tune I think it was a bit more noticeable. So the idle problem isn’t from anything I’ve done recently. The idle has gotten better actually & after the valve cover replacement. I just figured the oil in the plenum was affecting my sensors which affect the amount of air & gas to the cylinder. It’s been a very frustrating problem. I don’t mind replacing the parts since they probably needed it since the car is 16 yrs old.
I’ll look into the check valves though, my goal is to get the car running 110%. It’s running pretty good right now except the idle.
The thing about this idle problem is that I believe it had it before I bought it. I purchased it September of 2022. After putting headers & different exhaust on it and a tune I think it was a bit more noticeable. So the idle problem isn’t from anything I’ve done recently. The idle has gotten better actually & after the valve cover replacement. I just figured the oil in the plenum was affecting my sensors which affect the amount of air & gas to the cylinder. It’s been a very frustrating problem. I don’t mind replacing the parts since they probably needed it since the car is 16 yrs old.
I’ll look into the check valves though, my goal is to get the car running 110%. It’s running pretty good right now except the idle.
Update I put my scanner on it & the p1124 code came up that’s it. So I checked the map sensor again since this is my main focus since every time I’ve checked them they had a thin layer of oil on them. I thought I fixed this issue since I just replaced the pcv valve / valve cover. There are no leaks & it sounds really good. Today Sunday I ended up pulling the entire intake manifold out this time to clean it of oil since I saw the new map sensor with oil on it again. There was more oil in the plenum than I’d like to admit. It’s coming from the vacuum line like before. What could be causing this? It’s a new pcv valve cover on it that oil should stop correct? Any help is appreciated I just want to get this fixed.
Smoke test it, just smoke tested a Z3M with rough running and the smoke revealed leaks at the inlet maniforld joints just before the injector rail obviously the gaskets on the inlet tubes have gone hard and shrunk. The smoke was quite noticable but a visual check would not have revealed them. Got to have a good sealed vaccum system on BMW engines any leaks will play havoc with running and cause problems with fuel trims.
