M30B35 swap, runs rich..help

[hammertime]

I just purchased a swapped e30 with an m30b35 swap from a 91 5 series. The car seems to run a bit rich, has a brand new o2 in it. Any advice as what to check, or are there any diagrams for the wiring? I figured it has to be something not wired in incorrectly. Still has the m20 harness.

[kronus]

if it's running rich it will quickly foul 02 sensors. Can we have some details on the swap? Modifications to the engine? By the way it's an M30B35 ;)

Check out Frank M's swap writeup in the M30 subsection, it has a lot of wiring details.

[jlevie]

A 91 E34 5 series could have had an M50 2.5L or an M30 3.5L engine. It the car has an M20 harness, the M30B35 is more likely. But then, with the M20 harness, if that is really what is there the engine could be an M20B25.

[hammertime]

Sorry guys, it was an m30b35. The swap looks clean. No modifications. Although he did weld up a full 2.5" exhaust, cat deleted. It just backfires alot, idles kind of rough.

[603Racing]

Check the M30 swap write ups mentioned and verify all necessary parts have been swapped accordingly. Sound like maybe something electronic related to air/fuel delivery is not correct or maybe not working properly... MAF? ECU? Injectors? TPS?

How does it run at WOT? Not sure about the M30b35 MAF, but my older M30b34 MAF (euro '83 model) has an adjustable flapper.