2003 M3 attempts to run then immediately quits

[davidf]

A quick bit of background: My son recently purchased a 2003 M3 (Carbon Black on black) and we have been refurbishing it ever since. We have replaced rod bearings and rebuilt the VANOS among many other things. The car also had a cold air intake with no MAF and some sort of sensor added into the MAF electrical wiring...all since removed. I suspect the DME has been "tuned".

Anyway, the engine ran fine after our repairs but then all of a sudden (after overnight or two) the engine will no longer start. It is not the battery or starter as it turns over fine. The issue is that it attempts to run for a second, then dies with (black) smoke coming out of the tailpipe and a fuel rich smell.

Anyone have any ideas where to start? I have INPA and plan to read any fault codes this evening. What codes should I be looking for?

[Obioban]

Generally firing up for 1 second than turning off is an EWS issue.

Slightly thrown by the black smoke as a theory, but that's where I'd start my search.

[davidf]

Thanks, I am leaning that way also. Will check codes and try to reset EWS this evening with INPA. BTW, it is an SMG car, if that matters. Also, there has always been, since purchased (about 1 month), a delay between turning key to start and the starter actually engaging.

[Keith_MN]

SMGs are slow on start compared to full manual. Someone else can probably give better context, but there's an engineered delay there from what I understand.

How many miles did you put on between removing unknown MAF replacement sensor and replacing it with the stock arrangement? My first thought is that it may have an AlphaN tune and now you're back to the factory MAF - who knows what the PO did. I would flash the DME to stock, read codes, reassess.

[davidf]

I would say we have driven the car approximately 5 miles or less. The plan is to reflash the DME to stock, but hoping to drive it to the Indy shop to do so as I am not confident I wouldn't brick the DME.

Yes, who knows what was done previously. We also replaced the straight through exhaust with the factory muffler. But, still no cats.

[xansabi]

A quick bit of background: My son recently purchased a 2003 M3 (Carbon Black on black) and we have been refurbishing it ever since. We have replaced rod bearings and rebuilt the VANOS among many other things. The car also had a cold air intake with no MAF and some sort of sensor added into the MAF electrical wiring...all since removed. I suspect the DME has been "tuned".

Anyway, the engine ran fine after our repairs but then all of a sudden (after overnight or two) the engine will no longer start. It is not the battery or starter as it turns over fine. The issue is that it attempts to run for a second, then dies with (black) smoke coming out of the tailpipe and a fuel rich smell.

Anyone have any ideas where to start? I have INPA and plan to read any fault codes this evening. What codes should I be looking for?

This may be a long shot, but before buying mine I saw a carbonschwarz/black SMG car with a shitload of problems for sale. Did you get this one from Washington?

[davidf]

LOL, nope. Bought it in Houston...needs a shitload of work. So far parts cost has equaled purchase price, but it is getting there.

[davidf]

No real meaningful error codes, disconnected the MAF sensor and she fired right up. So, MAF took a dump as it ran great last drive. And, need to flashed to factory tune to hopefully solve rich mixture. Or, the tune does not like the MAF signal

[JakeM346]

Honestly sounds like a csl tune. If you say some sort of sensor wired in/ could you provide a picture of that. Might be ambient air/ or the other option somebody just wired in a resistor.
also have you cleared adaptations

[davidf]

I did not snap a photo, but I am (almost) positive it was a temperature probe reading ambient air temp as it was just zip tied to the MAF wiring harness. PO had an aFe cold air intake installed (for sale if anyone wants it). Good point, I have not cleared adaptations...will do so.

[sapote]

Running rich with MAF disconnected is normal as Dme defaults to look up table for fuel metering.
Smg start delay bc it needs to wait for smg oil pump pressure.