Hi all, recently swapped back to a punto again.
Replaced gearbox and HG earlier in the year.

Car runs spot on and quiet as anything. I keep thinking I'v stalled when i stop at the lights

Starts perfect from cold and very smooth.
If I start the car while engine is warm from previous run the idle gets slightly irratic then drops and cuts out after a few seconds.
Doesn't cut out if I rev abit.

1st thought was throttle body but that would effect if from cold. Am I right in thinking lambda sensor may cause this?

My first guess would be engine temp sensor (ECU thinks it's cold, thus gives far too much fuel -- you may even be able to smell richness).

Second guess is map/air temp sensor (combined on the MPI cars).

Of course, the first is testable with a multimeter.

Or wiring to either.

If no ECU light, (or no stored codes) TDC sensor has to be a culprit.

But any modern code reader should be able to catch the issue in real time. OBD2 does have its advantages!

If it was engine temp sensor it wouldnt give a reading on the temp gauge though would it?
The is no ecu light no but I thought tdc sensor would have more symptoms than just that.
Might be worth me investing in a code reader

If it was engine temp sensor it wouldnt give a reading on the temp gauge though would it?

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Nope. IIRC, just tells the ECU engine (but really coolant) temp, not the guage which is done elsewhere.

I got a cheap yellow one off eBay for less than £20 (for the Volvo) and so far I'm pretty happy with it. MES and a laptop is probably a better way to go for (OBD2) FIATs.

Oh yeah, I was thinking of coolant sensor? Where's the engine temp sensor again? Had to many other cars since my last punto

On Mk2s it's the green coded sensor on the extreme end of the inlet manifold, next to the thermostat. You have to take off the inlet mani to fit a new one.

I've no figures for the niominal values, but shouldn't be that different to the ones on Mk1s, where resistance goes down as temperature increases.

fingers99 said:

On Mk2s it's the green coded sensor on the extreme end of the inlet manifold, next to the thermostat. You have to take off the inlet mani to fit a new one.

I've no figures for the niominal values, but shouldn't be that different to the ones on Mk1s, where resistance goes down as temperature increases.

Click to expand...

You dont need to remove manifold to refit a new sensor
The housing just push's down

Ziggy

I thought that was the coolant temp sensor that controlled the temp gauge in the car.
I'm thinking there is 2 sensors and getting confused now

I'm sure I changed that when doing HG aswell, was for an old one though

Not a good idea! sometimes the hole they sense through -- if you get my meaning -- gets clogged up, which doesn't help.

Possibly, the reason I replaced was because me how clogged it was from the hg goin. May just be more crap moved about n clogging it again