When I got this used pump from a guy who said it was running fine on a wrecked truck with about 187,000 miles on it., the fuel screw was turned way out and not adjusted.
Got the pump and turned fuel screw in so it would run. Runs pretty good, and took it for a test drive and So right now here are the symptoms
1. LOW RPM Engine Surging:
Smooth idle, but when I put into drive, the engine surges and sometimes stalls.
Turning in the fuel screw helps reduce this, but the Idle RPM gets too high.
2. HIGH RPM Engine Surging:
Full throttle in Park or neutral, engine surges at high RPM's
Turning out the fuel screw stops this from happening, but I get low RPM surging.
3. THROTTLE KEEPS GOING:
When I give the truck full throttle and accelerate into second gear for 2-4 seconds, I then left my foot off the gas and the truck keeps going like at full throttle for 3-5 seconds. (scary). I have to turn it off and on real quick and then the engine returns to idle.
Please give me some ideas and what to do:
1. What causes #1 above?
a) I plan on testing the TPS. if I adjust that to specs, will that fix the low RPM surging?
2. What causes the high RPM surging?
a) is the pump weak or old and not performing properly?
b) is the fuel screw turned in too far?
3. What causes #3 above?
a) Fuel screw turned in too far?
b) How far can I turn the fuel screw in without over-stressing the pump.
THANKS
DEAN