Manager Forum

We have had a 1996 Chevrolet C1500 in our shop for a week. We have tried to set the timing with a Snapon Modis Scanner and it shows -45 degrees. Replaced Distributor, PCM, checked the camshaft gear (teeth), checked the timing chain, double checked the TPS sensor, and followed the MODIS scanner proceedure and snapped the throttle after every timing adjustment and no luck...it stays on -45 degrees. What are we missing to get this truck running in tip top condition again? Help!

no adjustments for timing. look into camshart retard setting. rpm must be over 1000 rpm and with a timing light it must read + - 2 degrees. generally speaking if the distributor was installed correctly (not just in and out) there is a very specific way to set it, aligning dots on the distributor is one, if you put a quarter against the intake on the left side as your looking at it and twist the distributor until cap hits it this will set the distributer. the cam and crank timing must be calibrated before the cam retard is set.

Turns out it was the timing chain. It had just enough slack in it to knock the timing out the same degree each time...negative 45. Sometimes the last resort should be the first!