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2007 Buick LaCrosse Crank No Start

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Old 07-16-2022, 06:51 PM
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Originally Posted by OldsManiac1990
your car doesnt have a camshaft-tachometer.. can you show me that live data?
these are a second apart


Old 07-16-2022, 06:52 PM
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The Camshaft sensor signal will also alternate between yes and no
Old 07-17-2022, 06:18 PM
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Originally Posted by RedCloud657
The Camshaft sensor signal will also alternate between yes and no

weird change from the series 2 days, no biggie seems normal then
Old 07-17-2022, 08:05 PM
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Originally Posted by RedCloud657
GM has the pcm send power to the fuel pump relay. There’* been some replies about this issue On this thread. There’* a wiring diagram that I posted that proves this and I’ve also checked this out on my other Buick 3800 and the PCM does send power to only the fuel pump relay.
If the PCM is commanded to energize the relay you need to check at that pin. Make sure the pin is in good condition and that it has good contact and pin tension. If you have B+ at the pin and good contact and not getting to the relay you have an open between the PCM and the relay. If all is good at the relay but missing the B+ you could just run a redundant line and test. You may decide to just leave it in place.
Old 07-17-2022, 08:16 PM
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Originally Posted by carfixer007
If the PCM is commanded to energize the relay you need to check at that pin. Make sure the pin is in good condition and that it has good contact and pin tension. If you have B+ at the pin and good contact and not getting to the relay you have an open between the PCM and the relay. If all is good at the relay but missing the B+ you could just run a redundant line and test. You may decide to just leave it in place.
Isnt it a controlled ground to the relay which allows it to run?
Old 07-17-2022, 09:58 PM
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Originally Posted by OldsManiac1990
Isnt it a controlled ground to the relay which allows it to run?
I don't have the diagram for it but there are some that are power controlled rather than ground.
Either way that line needs attention.
Old 07-18-2022, 12:26 AM
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I’ve checked continuity through that entire circuit especially from the relay all the way to the PCM and there are no breaks and no resistance in that wire. It’* perfectly intact. I’ve triple checked the pcm harness connecters also.
Old 07-18-2022, 08:12 AM
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Originally Posted by OldsManiac1990

weird change from the series 2 days, no biggie seems normal then
The rpm varies too much. It goes from 200 rpm to 1200 rpm within a second. The typical data value is supposed to be Yes for a present signal the whole time the car is running but it spams yes and no. Do you think I should try another cam sensor?
Old 07-18-2022, 11:00 PM
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Originally Posted by RedCloud657
I’ve checked continuity through that entire circuit especially from the relay all the way to the PCM and there are no breaks and no resistance in that wire. It’* perfectly intact. I’ve triple checked the pcm harness connecters also.
Pin tension is critical.
Old 07-19-2022, 02:20 PM
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Originally Posted by carfixer007
Pin tension is critical.
I’ll double check that just in case


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