5.25 I

[750bmw]

well last night me and my friend were in his 1993 bmw 5.25I and we drove to get some food when we came out of the restraunt and started his car the check engine light came on immediatly and than the motor started to rev.... it would rev to 2000 rpms and than drop to 1000 and than rev back up to 2000 and than drop back to 1000 it did this constantly and will not stop...what could be wrong??? has anyone had any kind of problems like this??? how do we get the check engine light to display the code?

[///M Power]

This could be one of many things. My easiest guess from your description would be Idle Control Valve. Clean it. Also check Mass air flow sensor, spark plugs, and O2 sensors

Edit: I can't believe im not sure but i cant rememebr if that motor has 1 or 2 O2 sensors. Someone else got the answer to that im sure..

[CBA]

::: cough :: IAC :: cough ::

[kirbanana]

could it be vacuum leak? i'd like to know in case i run into that problem with my newly acquired E34 525it. thanks!!

[Torque]

my dad's Eagle was doing a similar thing, and it was a faulty ECU... I haven't heard of a BMW with a bad ECU so far, but there is always a first...

[750bmw]

Originally posted by CBA@Dec 19 2004, 12:22 PM
::: cough :: IAC :: cough ::

[snapback]254303[/snapback]

IAC stands for what?

[billB]

Originally posted by 750bmw+Dec 21 2004, 12:22 AM--><div class='quotetop'>QUOTE(750bmw @ Dec 21 2004, 12:22 AM)</div><div class='quotemain'><!--QuoteBegin-CBA@Dec 19 2004, 12:22 PM
::: cough :: IAC :: cough ::

[snapback]254303[/snapback]

IAC stands for what?

[snapback]255007[/snapback]

[/b][/quote]

IDLE AIR CONTROL VALVE? or ICV=Idle Control Valve.

[attachmentid=16472]

[billB]

750BMW

Since the check engine light is on; don't u think it is a good idea to hook it up to a diagnostic; they do it for free at some Autozone stores! This will minimize all the guess work and save you $$$!!
regards
billb

[sp0rky]

and it was a faulty ECU... I haven't heard of a BMW with a bad ECU so far, but there is always a first...

You're kidding right??? lol BMWs and bad ECUs are a common match, especially on the older models.

REALLY does sound like the ICV though.