Hi all, I’ve been driving my ‘77 911S for a few months now after a top end rebuild and it has been great overall. However I have a cold start issue that has been annoying. It will start but seemingly on a few cylinders only for 30 seconds or so and sometimes backfire a bit. Then it fires all 6 and runs great!
I wanted to ensure my air/fuel ratio was good on this car and also my 79 928, so I got the GasTester a couple weeks ago. I finally busted it out today to check my well warmed up 911 and noticed that the ideal spec in the books for a US car is very different from a ROW car. The 1.5-3.0 for a US car and 1.0 to 1.5 for the ROW car.
Is this due to the emissions equipment on my US spec car? Since I’ve removed all of that, would I use the ROW spec? As it is, I set it to 1.6 at 960rpm and it seems to be behaving quite well though I can’t test the cold start until much later
Photo taken during testing - using my timing light to set the RPM
