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Old 03-14-2026, 02:34 PM   #1
Paul Y
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Join Date: Jul 2013
Location: Essex
Posts: 1,004
Here we go again! LM7 crank but no start

Gentlemen,

After the euphoria of fixing my injectors not working on the passenger bank had passed, went out to the shed today to move the truck out so I could start work on another project and it wouldnt start.

Symptoms first.

Cranks but wont start
Fuel pump doesnt run.
No spark
Injectors not pulsing

What I have checked

All fuses - good with none blown
Ohmed pump relay 86 to earth - was negligible so thats good.
Jumped pin 30 -12v to 87 pump runs
Checked power to PCM at pin 20(?) - the orange one - 12V
Checked continuity between PCM - pin 2 - green and white wire - and the CPS plug - All good.
CPS was changed as part of the prior trouble shooting
Plugged in other known good PCM - still no start
There is no voltage on the CPS plug with ignition on - I was lead to believe that there should be 12 volts.
Battery voltage is 11.8v

The amount of frustration I am feeling towards this damn truck is beyond description. As it was running and now isn't I am hoping that it is something really simple and one of you clever souls will go "Ah Ha you Bald Twit its...."

Over to you Gentlemen, what have I missed.

Paul.
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Last edited by Paul Y; 03-16-2026 at 02:00 PM.
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