325e Idle problems and more

[bumere46]

Hey guys, I recently acquired a 1985 325e. I am planning to fix it up and keep it as a daily driver. The problem that it has is that the car idles at 4000rpm when starting up and doesn't go down and it keeps increasing, as if I am pressing the gas pedal.
Every time I insert the key into ignition, aux fan runs at high speed, and the aux fan fuse gets hot and blows.
The car is indeed old, it does need some other work but these two are the main ones that I need to fix first.
Your inputs and suggestions are appreciated!

[flyboyx]

you really need to buy/download the bently manual and spend an hour or two going through the trouble shooting sequence. off the top of my head, the likely culprits are the water temp sender, idle control valve, cold start injector, o2 sensor, and air leaks in the intake.

i had a similar problem with an "e" i had several months ago. turns out some previous owner jackass changed the airflow meter to one from an "I". by chance, i found a nice "e" in a junk yard and purchased everything off the engine that (mentioned above) could have been the culprit. that was the first thing i changed and it immediately ran perfectly.

[Cephas]

I would also test the temperature controlled switches in the radiator that control the aux fan. There were two of them on my 86' ETA and I believe they were on the driver's side of the radiator.

Most likely someone wired the high speed to be on all the time, or the switch for the high speed has stuck on. Another thing to consider: it's likely the aux fan is going bad if it's pulling enough amperage to blow the fuse. Check it for binding when you have it out of the car.

[bumere46]

I just realized that the previous owner, replaced the instrument cluster and the tach redline is at 6500rpm...and 325E eta tach redline is at 4500rpm..
Would that affect my idle?

[tonerrrr]

I just realized that the previous owner, replaced the instrument cluster and the tach redline is at 6500rpm...and 325E eta tach redline is at 4500rpm..
Would that affect my idle?

No. However, if the cluster is switched, your fuel gauge may read incorrectly if it wasn't swapped with your normal eta cluster. Be careful, the mileage in the eta's are good, but not THAT good ha!

Regarding the high idle, since you have an eta car, look above where your glove box drops down. There's your normal DME computer then an additional green idle control module (ICM). If this is unplugged or half plugged in, your car will idle very very high, ask me how I know.