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Gary
Gary, GMC Technician
Category: GM
Satisfied Customers: 15714
Experience:  15 years gm master tech/15 years ASE master tech
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Having same issue posted here. Replaced distributor, cap,

Customer Question

Having same issue posted here. Replaced distributor, cap, rotor, plugs, coil, wires, and cps. Still kicks back when starting cold. Turns over perfectly when coil is disconnected.
Submitted: 1 year ago.
Category: GM
Expert:  Gary replied 1 year ago.

I am sorry your having this problem

replacing the distributor and crank sensor it made no difference at all ? any better or worse ?

Customer: replied 1 year ago.
No difference at all. Almost seems it is hydrolocked but if you disconnect the coil, it turns over perfectly. Of course I figured that out after doing all the work yesterday. Your previous answers led me to the crank position sensor this morning. I tried disconnecting the coil first to see what happened and when it turned over I was sure the cps was at fault. Unless it is bad wiring to the cps? Runs fine after it is warm. I have not gotten it to run this week since it kicks so hard I don't want to make it worse.
Customer: replied 1 year ago.
there are no codes.
Expert:  Gary replied 1 year ago.

when these kick back with a new distributor in it with a good bottom gear on it

to correct this issue as it seems its changing the timing too much causing this issue one of 4 things will fix it

a GM crank sensor 10456607

they sell crank sensor shims after a GM sensor is installed and it still does this shim out the sensor 1 shim if it still does this try 2 shims

if it still does this and the wiring is good to the computer then either the ignition module is causing this problem or the computer is

there is nothing else left to control the timing

Customer: replied 1 year ago.
The sensor did come with shins but I did not use them. I measures and there was plenty of clearance. Also the old sensor had no sign of mechanical contact. I can try putting one shim in at s time. Easy enough. How would the ignition module advance the timing? Any way to test before I go and buy one? It has slowly gotten worse to where we are now so I don't think it would be the computer. I will try shimming.
Expert:  Gary replied 1 year ago.

the crank sensor signals the icm that signals the computer and if the icm is not sending the correct signal to the computer this can happen

try 1 then 2 shims and see how it is be sure the wiring to the crank sensor is good

Customer: replied 1 year ago.
I will try the shims now. Any chance you know the PIN numbers for the wiring? I have a Haynes manual and does not give me the ignition wiring. Everything but that.
Expert:  Gary replied 1 year ago.

here you go