I was wondering if anyone knew what the base timing for a 1988 GMC 4.3 is?

I am having trouble with the motor making a lot of noise under idle, and when its brought just off idle, about 90% of it disappears. I am told that the problem could be a hydraulicing lifter. I want to first check all the valves for lash and make sure the timing is set before pulling the intake. We tried tightening up the valves and the noise has gone away, but the truck isn't running very smoothly. If anyone knows, I wiould appreciate it

Thanks

 

You still have the ECM hooked up and TBI right? If so your suppost to use the timing sticker specs under the hood or on the fan shroud, they are usually 10 to 12 degrees BTC. Thats static timing as the ESC (using the knock sensor and ESC module that it bolted to the firewall next to the distributer) will adjust the timing as you try to set it, so you need to dis-able the ESC by either un-plugging the brown wire under the top forward edge of the floor mat on the passenger side, or else use a paper clip to ground the ALDL from pin "A" to pin "B" (the top right two pins on the ALDL) then set your timing with a timing light.

OK adjusting the valve lash too tight will cause bad idle as the valves dont close at the right time, or they dont seat all the way. You should have set valve lash with the valves seated all the way (check your service manual on which valves to adjust after you set the crank to TDC), spin the push rod while tighting the rocker arm until you feel slight friction, then tighten the rocker arm one full rotation on a 1988 4.3ltr.

kingslam