Different Idle rpm at different temperature

[thrash]

my car idles after being started, at 400rpm at low ambient temperatures, and then climbs up slowly to 700 - 800 rpm when the engine is warm.. It's also more likely to stall if i'm too quick on the accelorator until it has wamred up..

on hot days, it will get up to 800 rpm quciker.. but will eventually end up idling at 1100 ro 1200 rpm when the engine is up to temperature..

anyone have any ideas on what the cause of this could be?

[wa_greg]

you need to check if your engine coolant temp sensor is working
then do the throttle reset prcedure

[Alspos]

The auto idle thingy is jammed. It lives on the back of the throttle body and has a wter hose going into it. When it's cold, the plunger is up, when it's warm the plunger is down. When it's jammed it doesn't do anything so idles like you describe. Learn to drive with two feet while it's cold. Or pull it apart and see if you can free the plunger thingy.

[RiceThief]

anyone have any ideas on what the cause of this could be?

Because its a starion :P

[Junkers]

I had the same problem Al is talking about, found it came down to the screws on the auto idle being loose and out of adjustment (assuming you have an early style injection system)

[thrash]

i actually have the later model tbi (without the 'eci' sign on the top of the thingo)..

so i suppose i should just work on going mpi sooner eh? :beer

the thing i find interesting is that aftermarket ecus don't actually retard timing based on knock sensor output or anything.. so that would mean if your engine is pinging on an excessively hot day for example, the ecu wouldn know or care?!

didn't know this until recently.. yeah yeah i know i'm a noob

[4gpwr]

the thing i find interesting is that aftermarket ecus don't actually retard timing based on knock sensor output or anything.. so that would mean if your engine is pinging on an excessively hot day for example, the ecu wouldn know or care?!

There are to many variants of knock sensors on the market for a reliable result .
Temperature compensation , timing can be adjusted , mostly.

I've got a cheap turbo x , knock , shift light with a new nissan knock sensor , last time it was on the dyno I adjusted its sensitivity comparing it to a knock box , with a consistent result .

Depending on the set up of the car , chasing every last deg of ign timing is not for shallow pockets .

[redzone]

thrash, your idle motor is faulty, or the ECU is not sending it the right signal..