Looping idle Problem.. Already replaced IVC, ICM, & DME?

[driftin8ez]

I just purchased my second e30. An 87 325 automatic. I also have an 86 es 5speed. Now the new one i just picked up (Auto 87) has this annoying problem i cant seem to track down. It has the looping idle issue. I replaced the dme, icv, & icm with the known good ones off my 86 and i still cant seem to get the icv to vibrate while the power is on and the engine is off. Basically the idle control system isn't working causing my looping idle issue however i know that all the control systems involved with the icv are known good. Is there something else added to the auto cars that control idle as well? Oh ya also my #9 fuse keeps blowing which i just found out is (idle control Fuel delivery)?

Thanks for any help guys. This is my first post on R3Vlimited so be nice. LOL

[NomadE30]

I would check out your TPS, possibly it is not getting back to idle position and staying in open. That's my problem if mine starts the looping i pull over pop the hood and push back the throttle and it goes back to normal idle.

But if it's blowing a fuse it has to do with something messing up really bad..

[driftin8ez]

I did a few other tests after I posted. Tps seems to be fine. There must be a short which would really suck. Is there any circuits I could try and test?

[NomadE30]

from what i can see in wiring diagrams i would check your Oxygen sensor wires along with your diagnostic wires.. Thats all i can see hooked up to fuse 9

[driftin8ez]

Ok we are definitely on to something here. The o2 sensor on these cars are 3 wire right? so maybe the heater wire is shorting out somewhere? Also I'm not sure if this should be like this but for some reason the red service oil light stays on even when the key is out and the car is off. Is there any way to reset that or is that just something screwy with the cluster circuit board thing? Maybe it could be the short im looking for.

[NomadE30]

try taking out the cluster and run the car see if it does it..

Car should run with it out, mine does

Also is it a 325i or 325e?

[driftin8ez]

I got it! i just unplugged the o2 sensor and bingo! no more blown #9 fuse and car idles perfect! So wtf is going on with the o2 sensor that it is blowing the fuse. I hope it is an internal short and not harness related. I'm hoping that getting a new sensor will solve.

Thanks alot for all the help. I really appreciate it.