986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Intermittent crank-no start

clueless1 · 05-01-2019, 08:05 PM

Hi there,

986S which has intermittently been not starting. This seems to happen only when it is warm. After I come back a few hours later the car starts again.

The tach moves slight when I turn the key to on position (regardless of whether it starts or not) — ie up to 0 rpm.

I bypassed the fuel pump relay with no change. The fuel pump sounds like it is coming on. No CEL.

When I crank the engine and the car DOES start I see a subsequent tach bounce initially (eg up to around 200ish and then it goes to 1000rpm on ignition). When I crank and does NOT start I see no tach bounce.

If I understand correctly, this is what a CPS fail looks like? Is there anything else I can do to check other than replacing the part?

05-01-2019, 08:05 PM	#1
clueless1 Registered User Join Date: Aug 2007 Location: Canada Posts: 65	Intermittent crank-no start Hi there, 986S which has intermittently been not starting. This seems to happen only when it is warm. After I come back a few hours later the car starts again. The tach moves slight when I turn the key to on position (regardless of whether it starts or not) — ie up to 0 rpm. I bypassed the fuel pump relay with no change. The fuel pump sounds like it is coming on. No CEL. When I crank the engine and the car DOES start I see a subsequent tach bounce initially (eg up to around 200ish and then it goes to 1000rpm on ignition). When I crank and does NOT start I see no tach bounce. If I understand correctly, this is what a CPS fail looks like? Is there anything else I can do to check other than replacing the part?