1992 K1500 unable to adjust timing
 

I am having a very hard time figuring out what is wrong with my truck. I recently purchased a 1992 4x4 X-Cab with a bad motor. The motor has been pulled and rebuilt to a 383 Stroker with the stock cam. I installed the motor, was able to set the timing at an advance of 12 degrees. The motor had a bad ping in it so I unplugged the computer lead on the firewall, hooked up the timing light, and now I am unable to adjust the timing at all. I pulled the distributor out to make sure it was in good condition and it appears to be ok. It doesn't respond to any adjustments no matter how much or how little I turn the distributor. The motor will run smooth and never act up until the distributor has been turned enough to cut off the engine. I get the infamous Code 42 but of course only when I have the computer lead unplugged. I am at wits end with this truck, I have replaced the ECM, cap, rotor, plugs, wires, ignition module, O2 sensor, Knock Sensor. The motor had 170k on it when I pulled it out. I don't know what is wrong, someone please help. Is this a simple distributor problem or something else?????

Ok. Today I went into the garage after not touching the truck for about 2 days. When I climed into the engine compartment I set my hand on the top of the distributor to stay balanced. As I layed my hand on the top of the distributor it moved. This seemed odd to me seeing how I tightened the distributor down the last time I attempted to time the motor. So this leads me to grab the spot light and watch the distributor shaft as I turn the cap. I found the shaft to be stationary and only the cap moving. This REALLY gets under my skin. I pull the distributor and find that the mounting plate for the distributor cap has come loose from the distributor shaft allowing only the cap to move, not the distributor. This is a very valuable lessoned learned. All of you who are having timing issues with your trucks need to check this on your distributors.

ha, thats awsome. and still quite embarrasing at the same time.

gotta remember that one, never heard of that before but thanks for sharing