Vicious95Z28

Hey guys, I have a quick question. I bought a 140gph "black" pump w/reg. from ebay. It's a ProComp pump which could be a problem but I was trying to save a few buck over a Holley blue which I may end up having to get anyway.

O.k. I have bought one of the Jeg's wiring harness with relay kits but I'm yet to install it. Right now it's just hooked into a ign under the dash in the fuse box. The problem is after the truck runs for 20-25 minutes the pump starts to fluctuate, it's wierd really, and the other day it dropped to like 3lbs and pretty much quit. I can turn everything off and let it sit for a while, fire it back up and all is well. It almost seems as if there is too much pressure build up that cant be released when it's just idling, so far the trips that I've driven it up and down the road seem to be fine.

The regulator is also one of the Holley type knock offs with 3 3/8 npt ports, one in the bottom bringing fuel in and one on each side. Do any of you guys try to bushing down one side to a 5/16 and run it to a return to try and relieve some psi, will this work or with a return will the pump not be able to keep up?

Also, could the problem be that the way I have it wired now be causing a voltage fluctuation. I'm gonna try to get the relay kit wired up by the weekend but I don't know if it's the remedy for the problem, either way it should be on there.

Sorry for the long post, I was just trying to provide as muh information as possible.

James

Injuneer

What vehicle are you asking about? Some kind of truck, it appears. Is it carb or fuel injection? The Holley Blue is a low pressure pump... hence a carb???? What kind of flyhwheel HP is it making? Does the ProComp pump include a fuel pressure regulator, like the Holley Blue?

Is the inline pump running in series with an intank pump? If so, how big is that pump? It not, what does the plumbing between the tank and the pump look like? What sizes are the lines? Is there a filter in the suction side of the pump? .... in the discharge side of the pump?

From your question on the fuel pressure regulator, it appears you have a single line running from the pump to the regulator, no bypass on the regulator, then a single line from the regulator to "something".... either a carb or a fuel rail? What pressure is the fuel system supposed to operate at?

Vicious95Z28

Fred, it's carbed. It's actually a little S-10 pickup that I built an engine for. It'a 2.8L bored .040 and stroked, so the whole thing is now a 3.2L It's got ported heads w/LS6 beehive springs Comp locks and retainers, a 216/226 .466/.496 112* cam, a Edelbrock TorquerII intake and 450 Holley 4BBL CARB.

The pump is supposed to operate from 4-14 lbs depending on the spring thats in it. The spring that's in it now is supposed to keep it in the 7-14 lb range. The regulator is identical to a typical Holley reg and so is the pump pretty much. The lines are 3/8 lines no filter before the pump and only one see through type filter after the pump & before the carb.Oh, the pump is about 18" from the tank max, I know these things don't like to pull as much as push and that's about as close as I could get it and keep it in a safe area. The filter appears to be staying clean, there isn't any junk in it. There is a single 3/8 line to the carb from the reg. and the other port is blocked off, so 3/8 in, 3/8 out , the other port blocked.

The ProComp pump is the only pump on it, it shouldn't need any moreof a pump than that, it's prolly only making 200-210hp if that. Hope this helps Fred, need anything else?

James

Injuneer

That's a HUGE pump for a 210HP engine. It will flow about 120 GPH at 9psi, if its a direct copy of the Holley Black. You need about 17 GPH, so the pump is struggling to operate at about 15% of its capability. I don't have a lot of experience with electric pumps for carbs, but it sounds like the pump may just be way too big and not happy being choked down the way it is.

You could solve the problem by using a "bypass" style regulator. This is the Holley version:

http://www.holley.com/12-803BP.asp

Not sure if that is equivalent to your "ripoff" regulator, but its worth checking out.

Vicious95Z28

Fred,

That's basically the reulator that I have. Does it matter which outlet you use for the bypass or are they basically the same?

Injuneer

Yes, I think it matters... there's probably a spring in there that closes down the return line, to hold whatever pressure you set with the allen screw on the top.

But I've seen Holley regulators that look similar, but are not bypass regulators.... they have two outlets to supply both sides of a carb or two carbs.

Again... I have never used an electric pump on an engine with a carb, so I am not real knowledgable on what works and what doesn't. But you've got more capacity in that one pump (450 LPH) than I have in the two pumps (2 x 205 = 410 LPH) that comfortably supply an 800HP nitrous motor. I only run one pump at 500HP without the nitrous.

Vicious95Z28

It's got a lighter spring that will reduce the output, I wonder if I should try that?

Vicious95Z28

O.k. I tried the other spring and there was a difference. I still think it could benefit from a bypass reg. which I think I'm gonna get but at least this made a difference.

Injuneer

I think the bypass regulator is the way to go.

Vicious95Z28

Yeah, I ordered one today.