m30 running rich at idle, cutting out under load. Any ideas?

Discussion pertaining to positive pressure E28s.
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E30battlewagon
Posts: 10
Joined: Apr 06, 2017 7:59 PM
Location: Maine

m30 running rich at idle, cutting out under load. Any ideas?

Post by E30battlewagon »

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?
tschultz
Posts: 4059
Joined: Mar 01, 2009 7:58 PM
Location: Denver, Colorado
Contact:

Re: m30 running rich at idle, cutting out under load. Any id

Post by tschultz »

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

But take a look here:

http://www.hiperformancestore.com/motronic.htm
RDAvena
Posts: 514
Joined: Feb 12, 2006 12:00 PM
Location: Falcon, CO

Re: m30 running rich at idle, cutting out under load. Any id

Post by RDAvena »

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.
marc79euro645
Posts: 513
Joined: Dec 08, 2008 11:33 PM

Re: m30 running rich at idle, cutting out under load. Any id

Post by marc79euro645 »

Slowly drops to 10 when? When idling, or during a hard pull?
E30battlewagon
Posts: 10
Joined: Apr 06, 2017 7:59 PM
Location: Maine

Re: m30 running rich at idle, cutting out under load. Any id

Post by E30battlewagon »

Idling
marc79euro645
Posts: 513
Joined: Dec 08, 2008 11:33 PM

Re: m30 running rich at idle, cutting out under load. Any id

Post by marc79euro645 »

What fuel pump are you using? I recently had to replace fuel pump as 1 stock pump was not enough for boost.
E30battlewagon
Posts: 10
Joined: Apr 06, 2017 7:59 PM
Location: Maine

Re: m30 running rich at idle, cutting out under load. Any id

Post by E30battlewagon »

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
marc79euro645
Posts: 513
Joined: Dec 08, 2008 11:33 PM

Re: m30 running rich at idle, cutting out under load. Any id

Post by marc79euro645 »

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?
E30battlewagon
Posts: 10
Joined: Apr 06, 2017 7:59 PM
Location: Maine

Re: m30 running rich at idle, cutting out under load. Any id

Post by E30battlewagon »

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.
9mil
Posts: 268
Joined: Sep 27, 2010 8:43 PM
Location: Atlanta, Ga

Re: m30 running rich at idle, cutting out under load. Any id

Post by 9mil »

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