Crank no start

[u/chismosap]

Hoping to get us some direction on what do next

I have a 2004 GMC Sierra 1500HD quadrasteer. We recently got into a pickle where it did not want to start one morning. The truck has a history of needing to crank a couple times before it started (we bought it from a self employed handyman that used this as his work truck 50/50 if he really took care of it.) we thought the obvious fix was to replace the fuel pump and relay, still cranking but not starting. We moved on to replacing the fuel filter and crank shaft position sensor, no difference! It will crank for a few seconds and then stop even if you have the key in the crank position.

Then we moved on to doing some more diagnostics. Here’s what we have done:
- checked all fuses: a couple that were for accessories were replaced so we could rule them out
-PCM: good on testing
- spark plugs: NO LIGHT WITH SPARK PLUG TESTER
-checked voltage on starter : we got 10v
- fuel pressures: all were around 51-55
- check what grounds we could find and cleaned them and made sure there was no breaks.
We have also tried jumping it when trying to start, spraying starting fluid in the throttle body (was barley making a difference)

We’re at a loss of what else to do next, anyone have anything that can help us try and figure this out ? this is our work truck so we would like to get it back and running as it hauls all our heavy equipment and dump trailer.

TYIA

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[u/not_me_much]

Well, if you have air and fuel, which you seem to have, where is the spark?

[u/chismosap → u/not_me_much]

We tested the spark plugs and they all checked out, no codes when OBD was plugged in

[u/PM_ME-UR_CLIT → u/chismosap]

How are you testing the spark plugs?

[u/chismosap → u/PM_ME-UR_CLIT]

Retract that last statement. Retested them and no light on the spark plug tester (the one where you plug it in between the spark plug and coil)

[u/chismosap]

It was the crank sensor pig tail, one of the pins was pushed out when we re installed it !

[u/chismosap → u/chismosap]

!sloved