1998 GMC C1500 Timing

1998 GMC C1500
52,000 MILES • V8 • 4WD • AUTOMATIC
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SHAWN DS24
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I have a 1998 GMC 1500 4WD pickup with a 5.0 L (305) engine. I was just replacing the distributor cap, rotor, spark plugs, and wires when I noticed that the distributor (that actual part that goes into the intake manifold and down into the oil pump) one of the "ears" that is threaded that the cap gets bolted to was broke, so I had to remove the distributor shaft from the intake manifold. I have now put it all back together and the timing now seems off. The truck runs but it "spits and sputters" when you put it under load (in drive or reverse). Under the hood it says "engine spark and idle speeds are automatically controlled, do not attempt adjustments". Does this mean I need to take the truck in and have it serviced and hooked up to a computer or monitor to have the timing fine tuned?

Shawn S.
Apr 12, 2009 at 9:17 AM
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MERLIN2021
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Did you put a mark on the manifold to aid you in installing the new one? You might be off by a tooth one way or the other. Put #1 at TDC on compression stroke, then see if the rotor point to #1 firing position.
Apr 12, 2009 at 10:03 AM
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SHAWN DS24
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Thank you for you input but I have found on other forums that I will have to hook my truck up to a scanner / computer to have the timing fine tuned to the cam shaft sensor.

I have lined up the mark on the balancer wheel with the mark on the timing chain case to get the #1 up on top dead center. I have also tried taking the distributor out and moving it back and forth a tooth or two but it then runs worse. Also tied to adjust the distributor by loosing the distributor clamp and turing it ever so slightly and it still has not worked. I am pretty sure I have it in the correct position now as it does run but not great.

So I guess I need to have it hooked up to a sensor or computer now but thank you for your input.
Apr 12, 2009 at 12:18 PM
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