Intermittent shut off problem
 

Hi all.

I have an intermittent shut off problem with my 911SC. The engine does not stop immediately when turning off the ignition switch. Any ideas ?
Car is fitted with ITB’s and modern ECU.
It does not happen often and it does not bother me very much, but still want to find out why.

Cheers


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Look at all the grounds as the likely issue. Clean every ground, even if they look fine. Replace any ground strap that does not look pristine.

Most electrical issues are bad grounds.

Who knows how the new system is wired, but you might need a diode on the fuel pump or alternator circuit. That's my main beef with EFI conversions, they work fine when they finally get set up properly, but troubleshooting is a bittch. Most shops don't have a clue.

Try running the engine at a fast idle, say1500rpm.
Shut the key off.
If the engine keeps running then the charging system is back feeding, you have a really bad ground situation at stated above, or wonky wiring.

Describe how you wired up your fuel pump relay.
And if you are using the factory style red relay.

Subed.