QuestionI'd appriciate any help.!!
Please note details below and/or at: http://experts.about.com/q/BMW-Repair-805/1987-325i-accelerate.htm
Since I asked this question (below) I have tested the TPS as recommended. Clicks just after throttle opens. Center and one outer pin with 0 ohms when closed. Center and other outer pin when fully open, 0 ohms. No continuity between closed and open. The TPS seems fine.
I'd also like to mention that the 'backfire' i mention is actually both ways. (exhaust and intake.) Had my hand in the MAF, (messing with different 'flow settings' and it blew into the intake.
What's the best way to test the MAF. I replaced it with one from a running car. (30$) What should the resistance be as the flap moves? My MOTOR book states an even/steady increase from closed to open. Neither of my MSF's are like this. (Actually, both are quite similar.) Fully closed = 550, Just open like in idle ~1150, then rolls down from there to 120 at fully open.
1987 325i
Problem:
- Runs poorly. Idles "ok" Have to feather it until it warms up a little. Even then it 'searches'.
- Seems to be running rich (rich enough that I had to replace the plugs to get it to fire.)
- Seems like the engine will simply not accelerate past 2000 r's (approx)
- backfires as soon as the throttle is pressed. (If I start it with the TPS disconnected it does this right away.)
- smokes when it's accelerated. (this is why is seems to me it's running rich.)
What I've done:
- Replaced MAF with a used/working unit
- Replaced Motronic with a used/working unit
- checked all sensors with ohm meter. All seem to check out against the specs.
- ohm'd out each wire between all sensors/injectors and Motronic
- Replaced Plugs
- A shop replaced the FPRegular.
- Compression test. OK on all 6 cyl. (Not leak-down test, yet)
- fuel pressure test. OK based on spec. (Need to do this again to ensure the FPR is not bad.)
Since I asked this question I have tested the TPS. Clicks just after throttle open. Center and one outer pin with 0 ohm when closed. Center and other outer pin when fully open. Nothing
AnswerI see you have done lots of homework.You have replaced numerous parts and have a valid complaint.Although you have dug real deep into this problem I think you might have passed some other basics.
Having replaced parts questions are harder to answer.You said that you have had a fuel pressure regulater replaced,what was the fuel pressure?was it excessively higher than stamped on the regulator?The return lines too can cause a higher than normal reading.A faulty valve in the fuel pump would cause a high reading also.I belive checking the fuel pressure and the return lines(for kinks)will be the place to get into.It is obious you have replaced everything else.
When I worked at BMW they said the chances of a bad ECM was about 1 in a million and the chances of 2 being unmeasureable.So go back to the BASICS,I think your getting too technical and it is something you assume is ok.
If you have the VIN I might be able to help a little more.
