MyE28.com

Trying to figure out what's going on, when you first start the car the afr is right about where it should be a slowly drops all the way down to 10.0. It cuts out under load but revs freely while not. I think it's leaning way out when under load.

I've replaced
Ignition coil
Cap and rotor
Plugs and wires
Fpr
Coolant temp sensor
Fuel pump and filter (pump was junk when I bought it)
Tps
Replace the only vaccum line that seemed to leak
Fuel pressure is at 35 and spikes to 40 when revved (didn't think to test it underload while i had the pressure tester) The motor is boosted with a setup from a 7 series with a miller tuning kit. Bought the car not running, got it going and ran decent but broke up a little in the higher RPM. Now it won't pull at all. It's all swapped into a 88 320i wagon and definitely isn't the cleanest swap but couldn't turn it down for the price.

Any idea what to check next?

Not sure you meant to post in the F.I. section.

But take a look here:

http://www.hiperformancestore.com/motronic.htm

If it is a M30B34 check the cold start injector. With enough age those things tend to leak.

(edit) Oh it is Miller tuned. Check the MAF as well.

Slowly drops to 10 when? When idling, or during a hard pull?

Idling

What fuel pump are you using? I recently had to replace fuel pump as 1 stock pump was not enough for boost.

marc79euro645 wrote:What fuel pump are you using? I recently had to replace fuel pump as 1 stock pump was not enough for boost.

AEM 320 lph

That should do it, assuming you don't have a restriction in the line. I assume your using a hot wire maf with the miller setup. I don't know what to recommend for that.
Have you tried to talk to Miller?

welp, I think I figured it out. I opened up the ecu today and the miller war chip wasn't even in the ecu that was installed in the car. The one installed had a turner chip in it, found the other ecu in the back with the war chip but it won't even make the fuel pump kick on. Emailed miller and hopefully they'll help me get it squared away. Thanks everybody.

Did you get this resolved with Miller- interested in what transpired.