Offroad Trailblazers and Envoys

truck starts, but does not run.

Something not working right?

by Anthony Hernandez » Thu Jan 02, 2020 10:21 am

so i tried posting something on fb. no such luck, anyways ive deleted fb and have been looking all throughout here and gmt nation. none of my problems seem to match anyone elses exactly. Basically the engine cranks, it starts up, runs at 1k then after 6 seconds or so, it starts to bounce the rpms down half way to 500 and then slowly bounces all the way down and stops. This happens in about 10-12 seconds total. heres what ive checked so far;;;

crankshaft position sensor
swapped fuel pump
checked fuel pressure with key on 2 50, during the start up described it goes to around 60-63 until it shuts off, then slowly drops to 48-49 psi
checked every fuse and relay with tester light front and back under seat
checked every wiring harness with test light, found weaker signals (dimmer light) from throttle body harness.
checked wiring harnesses to all spark plugs.
used reader and have a p2432 code for the sai?

Any help would be great, i am out of ideas.
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by jdyonker » Thu Jan 02, 2020 12:51 pm

My truck was doing this. We found that the MAF sensor was not plugged in after we did a bunch of work. Plugged it in and everything worked perfect.
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by Anthony Hernandez » Thu Jan 02, 2020 2:43 pm

mine is def plugged in, and held with a zip tie.
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by DirtyBacon04 » Fri Jan 03, 2020 12:59 am

what happens if you try to rev it before it dies?
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by Anthony Hernandez » Wed Jan 08, 2020 11:32 am

dies the same, but slightly rougher.
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by Trail X » Fri Jan 10, 2020 10:55 am

Anthony, have you replaced both the Camshaft and Crank position sensors?
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by HARDTRAILZ » Mon Jan 13, 2020 9:18 am

Anthony Hernandez wrote:mine is def plugged in, and held with a zip tie.


I cracked the plug to a PCM and had to go ziptie route. It really never fully worked right until I swapped for a proper plug. May want to try to get itr right.

The simple thing that popped into my head was to leave the battery off over night so the thing really resets. I did not see you mention that and it might just help. In any way...I do not see it hurting anything.
I hate to advocate weird chemicals, alcohol, violence or insanity to anyone...but
they've always worked for me.
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by djthumper » Thu Jan 16, 2020 12:02 pm

I would go with what Kyle said. You can also undo the zip tie and try wiggling the wire. I had a similar issue on another vehicle.
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