Thread: Startup/Firing
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Old 01-02-2017, 08:21 PM   #4
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The ECU compensates for temperature (both air temp and engine temp) so a change in location/weather shouldn't make any significant difference.

The ECU will also enrich the air/fuel mixture at cold start if it detects low battery voltage or if the engine doesn't "catch" right away to improve the conditions for the engine to fully start.

Thus, I'd start by checking the fuel system - when was the fuel filter last replaced? Do you have the ability to monitor the fuel pump pressure while cranking the engine (when it doesn't start)?

I'd also take a quick look at the intake for oil from the AOS and check/clean the MAF.

With the problem being somewhat unrepeatable, it can be hard to accurately diagnose the exact cause. The good (!!) news is that usually these problems get worse over time and eventually you'll be able to repeat the fault which will help with diagnosis.
1999 996 C2 - sold - bought back - sold for more
1997 Spec Boxster BSR #254
1979 911 SC
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