revs drop, car jerks, been searching for 2 weeks

[TopOfTheLine89]

can a coil be an intermittent problem? i checked it with my meter and it checked out ok.

[sticksdaman]

I am having the same problem. I checked and cleaned the connections at the afm the icv along with each of the spark plug wires at the rotor and the coil. I've also recently cleaned my throttle body and afm. I thought it might have been a fuel issue, but two bottles of fuel system cleaner later and i have yet to see an improvement. I have noticed two things though,

1.) The problem seems to occur only when the car is warm

2.) It only happens below ~2000 rpms, above that it pulls strong and runs seemingly fine.

[838Kelli]

I had the same problem, check and clean the injector harness. Mine was filled with water and dirty to shit. I used a air hose to get the water out and electric cleaner.

It was a fuckin headache i ran thru everything and now the car runs fine.

[nando]

why the injector harness????? if the problems go away when the tps is unplugged wouldnt you replace the tps??? cus thats whats sending the signals.. the idle and wot switches.. i did the stopm test on my 87 325is and came back with a 1233 code. wot sensor.. so i unplugged it and been driving aroudn and so far it hasnt bogged or anything..

the TPS plugs into the injector harness (as does the coolant temp sensor). A coolant leak at the TB will get the injector harness plug/wires wet, and they corrode. And then Bad Things (tm) happen.

the leak can also corrode the TPS.. but for me, it damaged the wiring.

[sticksdaman]

http://www.e30tech.com/forum/showthread.php?t=58680

Lots of useful diagnostic info in here.

[acefreely02]

the TPS plugs into the injector harness (as does the coolant temp sensor). A coolant leak at the TB will get the injector harness plug/wires wet, and they corrode. And then Bad Things (tm) happen.

the leak can also corrode the TPS.. but for me, it damaged the wiring.

huh i didnt know that... always wondered where they plugged into... well my tps should be in by monday and im goin to order a cps too.. my cps read 46 when i tested it...

i had ran all of last weekend without the tps plugged in and the car was fine other than idleing high,, but thne monday morn comes and the car wont start again unless i hold the pedal down wile cranking, thne it starts and dies unless i hold the gas above 2000 rpm for a minute,,, thn the next day i tried the same way of starting and couldnt get it to rev past 2000 rpm.. jsut wanted to bog out and stall

[TopOfTheLine89]

Well i replaced the coil, coil wire and distributor cap and it runs fine now. Can't believe it was so simple. Think it was the dizzy cap no visible cracks or anything, didn't think a bad dizzy cap could make it miss on all cylinders and be so sporatic.

[SiGmA_X]

I am a mechanic, i need an electrician or someone who specializes in electronic diagnosis.

Mechanics specialize in electrical diagnostic, that is the majority of our job! Damn man.

Well i replaced the coil, coil wire and distributor cap and it runs fine now. Can't believe it was so simple. Think it was the dizzy cap no visible cracks or anything, didn't think a bad dizzy cap could make it miss on all cylinders and be so sporatic.

You are a mechanic and never thought to hook up a scope and look at the spark pattern? Of course the cap can make a misfire situation like that. No offense meant, but you might want to take a refresher course on engine diagnostic.

[TopOfTheLine89]

I pretty much suck and am going to refrane from calling myself a mechanic from now on. I am a person who replaces motors and transmissions and general parts hanger.

Anyway, i put a new cap and rotor on it and it runs but misses often and almost dies, also put new FPR on it. doesn't drive when it is cold out, it will idle but dies inbetween shifts if i try to drive it.

[ks6gp0]

fixed yet

You have probably found the problem by now, but since you haven't posted it I will throw my 2 cents worth in. I have a 89 325i, a 86 325es and a 86 325e. The 325es would run great for up to a week at a time and then all of a sudden it would loose power and die, occasionally it would run well when I shut it off but would not start when next time I tried. After both problems it would usually start and run fine after a half hour or so. I kept a good supply of parts from the 325e to swap out to find the problem. I think I must have changed everything out including all sensors, ecu, and anything electrical on the engine. After changing something out and it ran for awhile I would think it was fixed until a week later and.......
After about 6 months and changing everything out (2 or 3 times on some parts), I finally found the problem. I had looked for it before but did not see it. Where the harness connector plugs into the ECU in the glove box I found one of the terminals on the connector slightly (and I mean slightly) bent differently than the others. I actually took the head of the connector off and barely bent the terminal out so that it would make a better connection on the ecu. It must have been making a bad connection only at certain times. I have not had the problem since and it has been almost 6 months now.
Sorry for the long post but hope it may help someone else out. The moral of the story is that it could be any of the electrical connections, so you may want to use a magnifying glass while you are taking them apart looking for loose or bad connections.
So did you ever fix your problem and has anyone had this problem?
Russell

[slo325i]

i'm having the same engine pause/hiccup/jerking problem in my 86 eta. The CEL light flashes as the motor hiccups as well. I haven't replaced too many parts yet other than the i throttle body, i boot, and i icv. The TPS on the throttle body is good (came from a perfectly running car). I think I just read about the bad wiring for the TPS sensor. How could this problem be fixed?

justin

[gmvt]

I had the same problem with the same car. Will you tell me your solution. I finally caught the car on fire when I replaced the FPR due to the oring folding over. Had to put it away for the winter but am about to get back at it all. (fire not bad) I just bought a parts car. The motronic bent pin scenario sounds promiseing.Solution???
Thanks Bob
gmvt@tds.net

[slo325i]

Anyone found a good solution to this problem??

[slo325i]

Ok, I found the problem!! ONe of the injector plug wasn't on completely and as the car was moving, i guess it was creating a short to all the injectors causing the jerking/pausing....

So check all your connections guys. I feel good now.