Dual sd pump ?'s

[SDstroker]

Is it possible to have a weak pump or do they just quit working? I have a dual SD pump setup and when I get after it, the fuel pressure gauge drops quick like a single stock pump with 250/100s. Both are getting power and both are running. Both are factory pumps 150k on one and 200k on the other.
Anyway to test them?

 

[haulin99sdp]

whats the pressure drop to? what do you have your regulator set at? sounds like at least one of them is weak.... maybe both.... have you checked for leaks? do you have check valves plumbed in?

 

[SDstroker]

No check valves I thought they had them internally for some reason. I have the regulator at 67psi. I was going to pull the fuse one at a time and see if one drops faster then the other. I bet I can 0 the gauge. For 300/200 I would think they wouldn't drop like a rock like it does.

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[MadDiesel73]

My duals hold rock steady at 65 psi.. One or both have to be going

 

[SDstroker]

That's what I was thinking. I got another pump coming so I will do some swapping.

 

[obspsd]

My duals hold 67psi no problem

 

[David N]

Both of mine hold 70psi without dropping. But they are maxed out with 300/200's IMO.

Put your hand on them with the key on and see if they are vibrating. That should tell you if they are at least on or not.

 

[obspsd]

David they'll support atleast 50 more cc's. My hold pressure just fine. The guage never moves

 

[MadDiesel73]

I've herd duals support 400/400's No problem.

 

[obspsd]

I think that could be true

 

[TARM]

i think it would depend on how much you are using of that 400ccs. Many running them are using under 2ms PW 1.5-1.7 range. You start dumping 300cc+ of fuel and I think dual stock SDs may not keep up. Duals are pulling down what about 50-60 GPH? That is just a guess. IMO they are a great choice in general.

 

[Dieselboy.]

IIRC, marty ran dual SDs with 400/600s and now his 400/400s.

I'm running them with my 400/200s. And to be honest there isn't much more requirement between a 400cc or 250cc injector on a 200% nozzle. Until you start fuel side mods. Even at that I believe just over 200ccs is the max a 200% nozzle will inject at X milliseconds.

 

[Arisley]

Stupid question, but how big is your supply line? 67psi through a 3/4" line is a lot more fuel than 67psi through a 3/8" line.

 

[TrailerHauler]

Beat me to it Andy, I was going to mention the supply line. If your supply line is adequate I would probably try replacing that 200k mile pump.

 

[TARM]

Maybe more fuel in front of the pump but IMO no more fuel to the injectors as you are dealing with the same size fuel rails and ports. If the feed lines are larger than the feed port than its all the same. In terms of pump work its the total volume in front of the pump prior to the final highest restriction (regulator)

 

[SDstroker]

This

5/8" pickup to 5/8" hose, 3/8" hose from filters to pump and 1/2" to ITP fuel bowl delete RR.

I have a pump that going schizo on me. Today the fuel gauge didn't budge a bit.