bad idle

[asoto]

Hi there,
I need ideas about the bad idle in my car.
I changed the starter and the problem began.
I checked the ICV, its ok.
I changed to a Miller AFM with its chip in the computer.
The idle stays on the 1400 RPM when the right one before was 750, the spark plugs and cables are new.
There are not vacuum leaks, something else that I am not caring about? Once the computer is connected, it says the CO2 sensor, but with this kind of model and age, it is normal and the emissions are the right ones.
I have no idea how to test the TPS probably this is the problem.
I will appreciate any kind of ideas and suggestions.
Thank you so much.
Adan

[1995 540i]

Adan, what year is your bmw and how many miles? Also do u happen to know if u have a Nikasil or Alusil engine block? If your car has high milage and or a NiKasil block bad news for you buddy... get back to me and let me know and ill explain.

[genphreak]

It's worth doing the o2 sensor every 100,000km/60,000mi, so its worth just doing if the system tells you. Also can be destroyed if you ever get a head gasket problem. But your bad idle is probably a pipe/pipe connection/connector with a split/bad seal/pin hole or crack... etc.

[Tiger]

Bad O2 does not cause high idle speed...

[asoto]

The car is an e34 '89 525i with 240,000 miles on it and manual transmission, just changed the timing belt and the monoblock looks very good for its age, no pistons problems.
Just changed to HD rocker arms. I had two broken six months ago.[
Thank you so much for your help and support.
Adan

QUOTE=1995 540i;341998]Adan, what year is your bmw and how many miles? Also do u happen to know if u have a Nikasil or Alusil engine block? If your car has high milage and or a NiKasil block bad news for you buddy... get back to me and let me know and ill explain.[/QUOTE]

[asoto]

Thank you so much for the ideas, I will check them.
Adan

[asoto]

Tiger,
thank you so much.
Adan

Bad O2 does not cause high idle speed...

[genphreak]

High idle will be due to an ECU input: On an M20, the first thing to chk after vacuum is probably temperature sensors. If the ECU is logging errors, it is either right, or given incorrect data (eg. by something) and making an incorrect self-diagnosis.

[asoto]

Thank you so much, I will check and change the temperature sensors.

High idle will be due to an ECU input: On an M20, the first thing to chk after vacuum is probably temperature sensors. If the ECU is logging errors, it is either right, or given incorrect data (eg. by something) and making an incorrect self-diagnosis.