Engine will not stay running and CAM sensor reading is zero

DAN MARTINDALE

MEMBER
2009 GMC ACADIA
3.6L
6 CYL
2WD
AUTOMATIC
160,000 MILES

I've been having trouble with my vehicle starting and then immediately stalling. When I do a live scan I notice that the cam sensors are all doing counts, but it shows cam sensor RPM at zero. I think the problem may be there which is probably affecting timing.

What is the most logical cause of this? I am getting zero codes but show a very lean mixture of 29.3:1 command ratio and about a.9 equivalence ratio. Thanks for your time.

Thursday, January 6th, 2022 AT 9:06 AM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,108 POSTS

Hi,

The idea that it is running lean can be the result of low fuel pressure or an engine vacuum leak. Have you checked either of those at this point?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, did you check for a crankshaft positions sensor signal? That can prevent an RPM signal. However, I wouldn't even think it would start without either providing a signal.

Let me know.

Joe

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Thursday, January 6th, 2022 AT 5:19 PM