Used VE pump - Engine Surging and Fuel Screw - HELP PLEASE!

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Used VE pump - Engine Surging and Fuel Screw - HELP PLEASE!

Postby wilkyflex » Tue Mar 02, 2021 5:53 pm

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
wilkyflex
fuel screw!!!!
 
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Re: Used VE pump - Engine Surging and Fuel Screw - HELP PLEASE!

Postby Richie O » Tue Mar 02, 2021 9:04 pm

You keep adjusting the fuel screw, have you adjusted the idle screw?
1989 W250 727, 3.07 L/S, S300, P/S Intercooler, Stans exaust, Pump adjustments, 127k miles,297 hp
1993 W250 extended cab, rag, 4.10 l/s, 6x16's, HTT 62/71/14 piston l/p, Isspro EV series tach, fuel pressure, boost, oil pres, water temp, volt, pryo, 132k/ 301 hp
1992 W250 with NV4500, 3.54's, 16cm 60mm GDS H1C, ground stock cone, Isspro tach, pryo, boost, fuel pressure, slow, rusty, dented,180k
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Re: Used VE pump - Engine Surging and Fuel Screw - HELP PLEASE!

Postby wilkyflex » Wed Mar 03, 2021 10:17 am

Yes, I adjust the idle screw everytime I adjust the fuel screw. No luck yet
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fuel screw!!!!
 
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Re: Used VE pump - Engine Surging and Fuel Screw - HELP PLEASE!

Postby PToombs » Thu Mar 04, 2021 2:48 pm

The TPS has nothing to do with anything on the pump, it's only so the computer knows where the throttle is for overdrive.
#3, that's called runaway, it's from having the fuel screw in too far.
As for the surging, sounds like a governor spring issue. Who knows what the PO did to the pump, or if something is bad and that's why he got rid of it.
pete

Just enough power to break everything behind the crankshaft.
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