[chinna_n]

I ran into this problem after an indy mechanic replaced the starter motor. This mechanic did not have much experience in E90 series, thinking he could get the starter from bottom.

But later he ended up removing intake manifold, steering reservior! and replaced the starter.

He says he replaced intake manifold gasket(I think so too). Anyways, after starter replaced, car starts fine. But on every start, cold or warm start, the engine shakes wild, shaking whole car like crazy.

Engine RPM goes down as if it is stalling, and then goes up, and keeps doing it for couple of minutes until it settles for normal idle.

I absolutely did not have this problem before. I was wondering if this has anything to do with "Vacuum leaks". May be he forgot to tighten all vacuum hoses correctly?

Or could it be that oxygen sensor is touched/screwed up when intake is taken out?

After the work has been done, I do not have any trust in this guy anymore, as he missed the engine cover bolts, broke micro-filter mount bracket, god knows what else he missed, if he put all bolts/nuts back or not.

I should have done this myself, but when he offered excellent labor on this, I was tempted(also close by to my home) and gave it to him. Big mistake.

I think, if it got to be done right, we have to do it ourselves.

Now, instead of going back to him, I was wondering if anyone can shed any lights on this? could it be Vacuum leak? oxygen sensor?

Quick help is highly appreciated.

Note: It is extremely unlikely injectors or plugs gone bad in two days even when I have not used the car.

[chinna_n]

Any suggestions please!!

[humbertob]

Any codes present in the ECU ?

[aesfah]

Disconnect the MAF sensor and see if car runs better. If so, there's your problem

[RazRokz.!]

Bad coil pack possibly?

[nate5ks]

First check for fault codes. Then check all grounds for the ignition system, they are bolted to the valve cover. When those bolts go bad (they are aluminum) they rattle all over the place and cause stuttering and stalling. Any vacuum leak should trigger a CEL and problems with the MAF should throw codes so its important that those are read. If there are no definitive fault codes it is probably faulty grounding, I know from experience.

[Meeni]

Suspect you have an air leak, but it is kind of annoying to check.
So go with the easy usual suspect.
000. Read the shadow codes with INPA (or get them read by a BMW shop).
1. Check that all coils are well engaged
2. Visual inspection for all electric connectors that have to be removed to extract the intake manifold (there are many)
3. Visual inspection of the fuel line (it has to be disturbed to remove the manifold). Are all the injector properly inserted and secured?
4. Visual inspection of all vaccum hoses. There are plenty and visual inspection may or may not reveal anything.

If that doesn't help, you'll have to have a smoke test...

[chinna_n]

Originally Posted by aesfah

Disconnect the MAF sensor and see if car runs better. If so, there's your problem

I did try this. Disconnted MAF sensor. It did run better, but not as smooth as before.

I am guessing without MAF sensor input computer using some generic mapping.

As nate5ks and Meenu indicated, it is possible these guys did not connect the cables properly.

I just got the INPA/OBD cable from eBay($43 from russia ) , and after a marathon session of 6 hours I was able to get everything working(DIS, SIS etc). Just verified everything works and my laptop can read from car. One of the codes indicate open circuit for O2 sensor before cat. (ScanGauge reads as P112D, and one of the previous error code P0597 is not there any more!!?).

For today my brain is not working anymore... and do not want to do any mistakes, and screw things on my car. I will read usage manuals, and try to figure out exact error codes and post it here tomorrow.

Thanks to all for sharing their experience, knowledge and wisdom!. I would have been clueless without this forum. Still clueless, but atleast have confidence that I would be able get help over here.

Thanks

[chinna_n]

Ok, here are the error codes I read using DIS.

"2C2E Oxygen sensor before catalytic converter 2, overrun check -Signal during inertia fuel shutoff below" (can not see after that - is it Threshold?)

"2C3E Oxygen sensor before catalytic converter 2, line fault - open circuit, pump current path or virtual gro" (I can not see any further).

2EF5 - Map thermostat activation - open circuit - Fault currently not present.

The thermostat heater element error code (P0597 OBD code with scangauge) used to show until 2 days ago. It has been there forever. But now suddenly it says fault currently not present. It was there a day after starter replacement along with p0000 which might have come because battery is disconnected. Now both of these are not there.

I am somewhat puzzled here.

Is it possible that because of disconnected O2 sensor I am getting rough idle during start-up(warm or cold start), not a vacuum leak?
Also does this connected needs to be removed for removing intake manifold?

Anyone can they post/link photos of the location of this O2 sensor and wiring routing of this sensor?

Also, how come "Thermostat heater element open circuit" cleared itself?


FYI: I got a replacement thermostat and planning to replace thermostat and flush coolant. But now, if this is not an issue, I will work on it later.
Also, registered new walmart OE replacement battery which I replaced before starter replacement.
http://www.walmart.com/ip/EverStart-...ttery/16782659

[chinna_n]

Finally removed Microfilter, engine cover etc and able to look at the engine.

I want to make sure I am looking at right Oxygen sensor, and also to get the right part. Based on error code I was thinking it is bank 2 pre cat. (Bank 2 sensor 1). Which is firewall side top oxygen sensor. Can anyone confirm this for me?


Another thing, I am looking for potential vacuum leaks. Based on many posts it seems crank case breather hoses are problematic, especially after intake manifold is taken out. I looking at those hoses where they connect to intake manifold. I see what seems like a wrap on the hose, but it seems originally it had some clamp on it. Is there supposed to be a clamp?

Thanks

[chinna_n]

Can anyone confirm the clamp and oxygen sensor?