Idle stuck at 1500!

[aaandy]

Had a problem this weekend (98 Chim 400). Car started and was running fine then noticed that the idle was sticking at 1400-1500rpm. Revs were not rising and falling, would just come down to 1400rpm and sit there. Bit of an issue as I was typically in traffic which caused the temp rising to creep up and I couldn't hear the fans cutting in.

Later on normal service was resumed, car was running fine as had always done before, idle was as it normally is at about 800-900rpm, and the fans cut in at just below 90 degrees confirming fuse was still ok.

Then the same thing happened for a short time the following day. Bit perplexed as to what could be causing this intermitent problem. Has anyone any previous experience of this, or any of the normal invaluable advice on how I could cure this?

Andy.

[Stig]

Sticky stepper motor. Remove from plenum, clean/lubricate/replace.

Hopefully job done.

[Big Al.]

Yep! Concur with Stig, whenever mine starts to play up quick clean of the SM and a squirt of WD 40 (inside and out), usually solves the problem.

[aaandy]

Thanks. I'll get the bible out when I get in and try and give the stepper motor a clean up. Still a bit confused as to why the fans were not cutting in to try and keep the temp down.

Could this be related (my initial thought as everything was perfect before) or just a coincidence of have two things playing up at the same time?

[Big Al.]

aaandy said: Thanks. I'll get the bible out when I get in and try and give the stepper motor a clean up. Still a bit confused as to why the fans were not cutting in to try and keep the temp down.

Could this be related (my initial thought as everything was perfect before) or just a coincidence of have two things playing up at the same time?

Sorry! lost me a bit...you say your fans are not cutting in until 90? If thats the case, sounds about right to me.

My fans always (todate) cut in at 90.
I have had an overide switch fitted just in case they don't.

[chimburt]

have you had the ecu and birds nest, sorry, associated bundle of relays out at all?
mine did similar the other week because i had all that stuff out and must have stressed one of the connections. re-packed it all in the 'cupboard' and things were fine.
just a thought.
didn't affect the fans at all, though, but it ran like a dog and misfired occasionally.