914 Low idle when hot

[greg bryant]

I have a 1975 914 2.0 with stock fuel injection. The car starts fine when cold and runs great all time. When it has been driven for a while, the idle is very low. How can I increase the idle (when hot) without affecting other characteristics? One other bit of information..the car has a Crane electronic ignition. Thanks for your help!

[pbanders]

Without a more proper diagnostic of the ignition and FI system, there are many reasons that you might have a low warm idle. In lieu of that, I've often found the reason to be due to a rich idle mixture. It's OK during warm-up, but when fully warm, the overly rich mixture results in low idle. Get your CO checked and set the ECU knob at warm idle to the factory specification (IIRC, about 2%). You may find that after you do this, your warm-up behavior will be rougher (leaner).

[mejulihn]

I just had my '76 with FI smogged and Brad is correct. Setting up the proper mixture for warm idle may result in some poorer warm up behavior. Mine now runs a little rough during warm up where it did not do so before.

[John Rogers]

After checking the mixture, I'd check the AAR valve since I have seen several that have the idle adjusted so it is at normal speed when cold and when the engine warms up the valve closes and it gets a little too slow? Good luck.