E30 S50 Swap - O2 Relay Issue, Diag Port Issue, Breakup Issue

[dubseven]

E30, S50, OBD1, War Chip. silver label DME, EWS cut.

Parts replaced so far:
O2 Sensor (oem)
Crank Sensor (oem)
Cam Sensor (oem)
Coolant Temp Sensor (oem)
Fuel pump (twice)
MAF (oem)
Battery (deka agm)
Plugs (OEM)


Car does not like to idle really smooth. Some time ago, checked to see if O2 sensor was getting voltage. It was not. Checked relay, and the relay was feeding the DME 12V, but the O2 sensor was not getting 12v. Replaced relay, and sensor, and IIRC, problem was solved. DME stopped getting 12v (dme grounds relay to activate relay as far as I can tell?)

Car also likes to break up at around 6500RPM. Replaced DME and WAR chip, and the problem went a way for a very short while, then came back. Then, it started cutting out severely, idling VERY rough, dying. Felt like fuel pump dying. I would turn car off, restart, and it would chug along, but not run great. Replaced fuel pump. Checked fuel pressure. Etc etc. Problem still there. Went back to old DME, and the problem went away for a few minutes. Then it came back. So I checked the O2 sensor relay that I had replaced (above) with one from my parts car, and again, the DME was getting fed 12v via the wire that is supposed to ground the relay. Pulled the O2 sensor relay (hence removing the 12v feeding into the DME, where it should only be ground), and the car instantly came to a smooth-ish (but not perfect) idle. Car ran/drove fine. First 5 miles or so, hit limiter no problem. Then, as I got close to the house from work, it again is breaking up at 6500RPM.

And I am stumped.

Another side note: INPA 5.0 w/BMW cable refuses to connect to the DME via the 20pin diagnostic port. Both DMEs. Switched 12v power (pin16) in X6002 diagnostic port has no 12v. I manually applied 12v to pin16, but still no dice.

Ideas?

[Beej '86 325es]

I'm experiencing the EXACT same issue and replaced almost all of the same components trying to chase it down. I'm not getting any codes though, so I thought it was a tuning issue.
If you have a wideband O2 to verify, I bet you are running lean like I am. The breakup at 6500 rpm is detonation.

[dubseven]

Yeah it goes mega lean. IIRC idle lean as well but need to check.

[dubseven]

What tune do you have?

[Beej '86 325es]

It's a custom tune for my high compression S50. I'm still working with the tuner to get it running richer though. They explained to me that the DME doesn't know how rich or lean it is, but only that it is, and should self adjust to find that lambda=0...or bounce around close to it.

I just got done checking continuity on every wire having to do with the oxygen sensor and all checks out.

One thing that baffles me though. The Bentley (on page 130-9) says to:
"Disconnect the O2 harness and check the brown and green wires for battery voltage with the engine running. If battery voltage is not present, check O2 relay."

On a cold start, in a 50 degree garage I get nothing...a slight flicker of .01 volts. I verified my O2 heater relay was good by swapping with the fuel pump relay (they are the same p/n). I would assume the engine would not run if the relay was not good. The car seems to run the same if the sensor is connected or not.

I'd be curious if you are getting battery voltage. Your issue sounds so similar.

[dubseven]

Battery voltage to where?

[Beej '86 325es]

Battery voltage to where?

At your O2 sensor on the engine harness side. Between the green and brown wires.

[brody]

Send me the files from the WAR chip. We have an update going out next week that may solve your problem but I have to check the file to be sure that's whats causing your problem.

It not detonating when it's cutting out up high, it just has no fuel most likely.

[dubseven]

Hey Brody, I am using the S50 Performance file from the Miller wizard - need to email it anyways?

[nrubenstein]

So, who did your wiring and have you verified that it's correct? No power at the diagnostic port means that at least one thing is wrong.

[dubseven]

I need to re-check the diag connector. It did have constant 12v, but INPA showed no ignition on (switched 12v), but I dont remember if I checked it with a meter. I tried manually jumpering 12v into pin 16 on the diagnostic port, but INPA still didn't show ignition. Ill check it with a meter tomorrow at the shop.

[nrubenstein]

I have constant power, but no switched 12v.

Have you verified that your wiring at the C101/X20 is correct?

[dubseven]

Edited my post above. But yes, pretty sure its correct, I will be going back through it tomorrow if I get time. FWIW, car ran just fine for some time before this started happening.

[brody]

Yah send it over anyway just to make sure.

[328ijunkie]

yeah check your x20/c101