Questionhi, my brother and I are having engine problems. low power, no accel, pinging at takeoff, engine light at acceleration (resets every time truck is shut off.)
replaced cap, rotor, plugs, wires. put on timing light(disconnected tan/black ets wire). book says 0 deg btdc, which it was.plugged back ets and revved.timing mark goes from tdc to 4 deg atdc.engine sounds strained also. Shouldn't timing advance with rpm? replaced est module under cap, with no change.please help
joe and jason b
AnswerHello Joe,
There is a knock sensor, screwed into the block just in front of the starter.
If it senses a knock, like preignition, it will send a signal to the ecm, which will actually retard the timing, to prevent the knock.
You could unplug the knock sensor, just to see. But if that is what is happening, you should hear some clattering when accelerating.
The knock it is sensing could be from a real lean mixture due to low fuel pressure, or a vacuum leak.
Check for both.
The fuel pressure on tha throttle body system needs to be about 13 PSI whenever it is running, even under heavy load.
Van
