Yup, here we go ANOTHER rough idle post. Ive done some extensive research on this issue and after replacing several components i want to start documenting my progress somewhere and maybe get some insight from you smart guys and gals here at bimmerforums. So i just bought my 89 325ix and it had a rough idle problem. I replaced:
6 injectors
spark plugs(w8lcr) gapped at .028
Crank case breather hose
Fuel pressure regulator vacuum line going to manifold
The purge valve line from manifold to the purge valve
The line from purge valve to the charcoal filter
Cleaned MAF
Cleaned ICV
Replaced CPS(csr wouldnt start at one point during all of this....the sensor was bad)
The car has a rough idle only when warm. It doesnt seem to lose tremendous power (take that for what its worth)
It idles around 800 when its warming up(tach, gas gauge are erratic) and drops down below 500 sometimes.
M9st of the vacuum lines were replaced by vibrant vacuum hose which doesnt really seem rigid so idk if that has a factor in this
The head gasket appeads to be leaking on the fron part of the motor by all of the coolant stuff
No CEL
I dont mind putting more money into this car to get it running right but im mechanically inclined but not a mechanic by trade so thats why im making this post. Any help would be greatly appreciated.
The front oil leak is more likely the camshaft seal.
You still likely have a vacuum leak. Any air that can enter the engine is a leak. For example a bad seal on the oil filler cap is a leak. The nipples on the throttle body can also come loose. (Epoxy them back in.) Does your check engine light ever come on when sitting at idle?
I don't see an O2 sensor on your list. That's another likely culprit.
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1986 Delphin 528e - Roof rack equipped lumber hauler.
1989 Zinnoberrot 325iX Sedan - I miss this car. (Deceased)
1998 Avus Blau 328iC - Someone else's project now
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2020 Estoril Blue 440i xDrive cabrio - This car is a blast to drive.
I did replace the oil filler cap with a new one
I noticed before that the nipples on the throttle body are loose when I disconnect the lines to them. Could this be the problem
The check engine light has not come on for any of the idle issues.
It is a very slight rough idle like a small vacuum leak or something. The engine doesnt surge or act erratic.
Just wanted to throw in my 2 cents based on my experience with rough idles. A new DME can do wonders. If it doesn't have a 173, you should replace it anyway. Another culprit could be the AFM. When I replaced mine, I couldn't believe how well my car ran. This was after replacing all ignition components too. Both of these parts can be found as a reman, so they aren't too expensive.
no, that is the one for the fan. the engine temp sensor will be on the thermostat housing
No e30s again.
Last edited by BMWBurnout875; 11-09-2018 at 03:10 PM.
Just wanted to post an update on the progress so far.
I just replaced the spark plug wires, distributor cap and rotor along with the coil.
Also did the Engine Temperature sensor, deleted charcoal filter for the evap system.
Car still has a rough idle.
Last edited by BMWBurnout875; 11-17-2018 at 10:21 PM.
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