Low rpm surging

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Low rpm surging

Postby spencerdiesel » Sat Jan 30, 2016 9:38 pm

Friends '92 5 speed 12v. Roughly 1100 rpm and under it hunts like an old detroit. Load has no bearing on it. Any suggestions or ideas?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
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Re: Low rpm surging

Postby Remps » Mon Feb 01, 2016 4:10 pm

First thing I'd try is adding a second throttle return spring, if running just the one on the pump.
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Re: Low rpm surging

Postby spencerdiesel » Mon Feb 01, 2016 5:22 pm

Thanks I'll suggest that to him. I guess I should put both of mine back on then........
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
Posts: 1106
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: Low rpm surging

Postby spencerdiesel » Sun Feb 21, 2016 6:28 pm

Checked and I believe all is well with the throttle springs. It does have 320k and its an original IP, could excess wear play any roll?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
Posts: 1106
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: Low rpm surging

Postby adcotton » Sat Mar 05, 2016 7:01 pm

Mine does too. You can adjust the idle above or below it, and the power screw also has an influence.
Have changed injectors, lift pump , governer spring, turbo and fuel filter all at different times and it never changed.
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Re: Low rpm surging

Postby spencerdiesel » Sun Mar 06, 2016 10:15 am

Hmmmmmm
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
Posts: 1106
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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