Hi:

My Fiat Brava SX 1.2, when I start the engine from cold, the revs hit around 3,500 to 4,000 which I hate 'cause I know what engine damage could be happening. I can reduce the revs by putting it in gear with the handbrake on and letting the clutch out slowly. Once the revs are down, I dip the clutch and the revs stay down at around 2,000 long enough for me to get sorted and get the car moving, otherwise they start rising again back up to 3,500 ish.

I know that these days there are loads of sensors etc which can have an effect on engine running. Can anyone give me any (simple) pointers as to what the problem might be.

TIA

Ian

possibly something to do with the autochoke or lambda sensor maybe or the go faster pedal cable is sticking

There are a few possibilities:

ECU coolant temp sender.
Coil pack(s).
TDC sensor.
MAP sensor.
Vacuum hose leak.

Does the engine idle return to normal once the engine is warm?

Does it dissapere when warm? If so I would suggest Lambda, map or auto-choke.

If not, then throttle cable?

need more info. on first start of the day do not try to reduce the revs, just let it do what it wants. time how long it takes for revs to settle below 800rpm (750 is usual idle). what does the temp gauge say when it has settled? tell me the time and temp please. does this still happen when starting warm/hot engine? what is the idle speed when warm?

richcinq said:

There are a few possibilities:

ECU coolant temp sender.
Coil pack(s).
TDC sensor.
MAP sensor.
Vacuum hose leak.

Does the engine idle return to normal once the engine is warm?

Click to expand...

Yes it does. I am going to reply to Jug's post and give the info he / she requires.

My problem is the opposite to yours, I have low revs on start up... I have to keep giving it some throttle in the morning for a little while otherwise it will stall.
I am used to driving using the clutch uphill so I won't roll back in traffic, but with this Brava it's impossible... I have to use the hand break all the time

I guess I have to relearn how to drive ... or maybe there is something wrong with the car ?

Bravicssimo i still think your problem is probably coolant temperature sensor related. have you tried unplugging the coolant sensor to see how the car reacts. if it makes no difference i'd assume a faulty coolant temp sensor. then leave it unplugged and reset the ecu, the ecu will then use the default operating parameters which would make the idle higher and prove a sensor is at fault. in fact you can use that method to identify many sensor faults.

archer-ian i've been thinking about your problem and i get a mystic meg type feeling that you have a breather hose leak. i remember a problem car a few years ago that had the same symtoms as yours, after hours of diagnosis i got desparate and starting checking everything, then i found a breather hose which was split along the bottom where i couldnt see it. the loss of vacuum was making the car rev very high. its definately worth checking the full length of every rubber hose in your engine bay.

archer-ian scratch that idea, just read the posts again, forgat the revs were normal once the engine warmed up. its less likely a breather hose will cause high revs only when cold, although its still worth checking

Hey Jug,

The Temperature Gauge is now working very well and it responds to the car warming up, and when the engine is hot it will remain dead on the middle.

I will try and disconnect it, reset the ECU and see if that makes any difference....

thanks