5.3 rebuild no spark
Seems to me that if HPT shows no RPM when cranking then the PCM isn't getting the CKP signal or the signal is corrupt from bad ground or something. I can't remember for sure that HPT scanner shows RPM on load on crank on these cars but I'd expect it would.
Have access to a labscope? Very handy plugging into PCM pins to see the waveform the CKP is providing. Bad tooth/whatever shows up very clearly. Would also prove your timing isn't out 180 from the cam sensor waveform.
One thought, if your cam sensor is bad the PCM will attempt its backup strategy doing timing 180 degrees out I think on every-other start attempt as long as it has CKP signal, usually that appears to most as long crank with eventual successful start but that's one scenario that would fire but incorrectly.
Really seems like you should be getting some DTC's set.
Have access to a labscope? Very handy plugging into PCM pins to see the waveform the CKP is providing. Bad tooth/whatever shows up very clearly. Would also prove your timing isn't out 180 from the cam sensor waveform.
One thought, if your cam sensor is bad the PCM will attempt its backup strategy doing timing 180 degrees out I think on every-other start attempt as long as it has CKP signal, usually that appears to most as long crank with eventual successful start but that's one scenario that would fire but incorrectly.
Really seems like you should be getting some DTC's set.
Last edited by mk3cn4; Jul 7, 2022 at 10:09 PM.
Thread Starter
Staging Lane
Joined: Nov 2020
Posts: 55
Likes: 5
Here is a video of the reluctor wheel turning as a turn the crank by hand
https://imgur.com/a/0737Z48
https://imgur.com/a/0737Z48
Thread Starter
Staging Lane
Joined: Nov 2020
Posts: 55
Likes: 5
Update: I have spark and it is reading rpm
I pulled all the plugs and left them hanging outside the engine so that there would be very little load on the starter, and I finally am getting spark and rpm signal, so the issue this whole time has been that the starter was not turning the engine fast enough to start. Now the question is, how do I get it to spin fast enough? I'm running jumper cables straight from another running truck to the starter in the stand, and have successfully done this before, and it always has started slowly cold but never this slowly before.
I pulled all the plugs and left them hanging outside the engine so that there would be very little load on the starter, and I finally am getting spark and rpm signal, so the issue this whole time has been that the starter was not turning the engine fast enough to start. Now the question is, how do I get it to spin fast enough? I'm running jumper cables straight from another running truck to the starter in the stand, and have successfully done this before, and it always has started slowly cold but never this slowly before.
TECH Fanatic
Joined: Jan 2009
Posts: 1,065
Likes: 476
From: Bostwick, GA.
Update: I have spark and it is reading rpm
I pulled all the plugs and left them hanging outside the engine so that there would be very little load on the starter, and I finally am getting spark and rpm signal, so the issue this whole time has been that the starter was not turning the engine fast enough to start. Now the question is, how do I get it to spin fast enough? I'm running jumper cables straight from another running truck to the starter in the stand, and have successfully done this before, and it always has started slowly cold but never this slowly before.
I pulled all the plugs and left them hanging outside the engine so that there would be very little load on the starter, and I finally am getting spark and rpm signal, so the issue this whole time has been that the starter was not turning the engine fast enough to start. Now the question is, how do I get it to spin fast enough? I'm running jumper cables straight from another running truck to the starter in the stand, and have successfully done this before, and it always has started slowly cold but never this slowly before.
What's the cranking rpm?
