930 idling problem

[NBTBRV8]

I am having trouble with an idling problem on the 930. The car starts really well from cold but after a 3-4 minutes the idle starts to get rough and the car stalls. If the car is up to running temperature the cars still starts well but after about 20 seconds or so the idling starts struggling and eventually stalls within about a minute or so.

Today I changed the cold start valve with a reconditioned item but it didn't make any difference. I have also notice that the car back fires a lot more on the over run than it use to.

Any ideas and if so ways to test it?

Thanks

[dave mak]

A friend of mine has a 930 turbo & had the same symptoms. Car would not idle when hot.

after a trip to JZ Machtech, it turned out to be the fuel metering head, about £1800 fitted, sheesh!

But it cured the problem!

[Globulator]

£1800 is very cheap for a fuel metering head, especially fitted!

The cold start injector only injects fuel when cranking the engine, so will not affect anything else unless it was leaking.

Ideally you need to drive it, and see if the mixture at idle is rich or lean. Rich and it will drive fine, lean and it will be down on power and 'pop' (the best a turbo can muster on a backfire).

To be honest it could be anything, but start here:
www.pelicanparts.com/911/technical_specs/911_cis_troubleshoot.htm