Fuel Pump Help Please..

mackruss · **Posted:** Sat Nov 29, 2008 11:33 am

I have just installed the Huco fuel pump spec says it's a pressure pump and must be mounted next to the tank. Approx 3.6 PSI and 36GPH.

I did everything i'm not suppose to do, i mounted it in the engine bay about a foot from the fuel head and wired to the relay in the fuse box just to try it out. It also says mount horizontally but i had to mount vertically to line up the inlet and outlet.

Is it okay to use a pressure pump versus a suction pump and there is continuous power to the pump, it does not seem to cut off after 25 seconds, i wired the earth to a ground on the vehicle body. Is this going to run my battery flat.

Took the truck for a drive after bleeding and found that the slight hestitation i was feeling in second gear was gone. Initial impression good so i hope to hear that i can continue like this for awhile without doing any damage.

CRDMiller · **Posted:** Sat Nov 29, 2008 11:57 am

There's no reason why this would hurt you unless the pump's failure lead to a restriction against the suction of the IP.

That said it aint doing you a whole heck of alot of good. The Main reason to do a aux pump is to have positive pressure from the (as close as you can) tank to the fuel head in order to avoid the ip sucking air via plumbing that is not meant to deal with suction. The only other use that i can see from this setup would be to make sure the ip is not struggling vs additional complex plumbing like a cooler or additional filters etc.

That said if this fixes whatever problem you had, somehow, then good =) If your happy with it then there's nothing wrong.

Enjoy your jeep!

BlackLibertyCRD · **Posted:** Sat Nov 29, 2008 1:41 pm

When did we get the contention that the lift pump must be next to the fuel tank. The diesel engine had lift pumps on the engine as far back as I can remember. It's with the advent of electric pump that it started get moved around such as in the fuel tank or on the frame. An electric lift pump before the fuel head is just fine and will solve the problem that we have with air in the fuel filter. I been running my facet pump near the fuel head for about 1 1/2 year now with zero problem. BTW, even with the lift pump on the engine on much older diesels, the fuel filter came right after it and then the injector pump. Many of those lift pumps have a manual lever to prime the filters after changing them.

mackruss · **Posted:** Sat Nov 29, 2008 1:42 pm

The pump is pulsing at a low rate constantly even with the ignition turned off.

Is this a plumbing problem or the nature of a pressure pump. I can't understand why the pump operates with the ignition off though.

BlackLibertyCRD · **Posted:** Sat Nov 29, 2008 1:49 pm

mackruss wrote:

The pump is pulsing at a low rate constantly even with the ignition turned off.

Is this a plumbing problem or the nature of a pressure pump. I can't understand why the pump operates with the ignition off though.

You have to go into the fuse panel in front of the battery and hook to the primer pump relay. I think it's number 5 (middle) terminal that will give timer of about 30 seconds after the key is shut off. you just strip about 1 inch of wire and connect the positive (+) wire to it.

mackruss · **Posted:** Sat Nov 29, 2008 2:24 pm

BlackLibertyCRD wrote:

mackruss wrote:

The pump is pulsing at a low rate constantly even with the ignition turned off.

Is this a plumbing problem or the nature of a pressure pump. I can't understand why the pump operates with the ignition off though.

You have to go into the fuse panel in front of the battery and hook to the primer pump relay. I think it's number 5 (middle) terminal that will give timer of about 30 seconds after the key is shut off. you just strip about 1 inch of wire and connect the positive (+) wire to it.

That's what i've done but there's still power to the pump with the ignition off.

mackruss · **Posted:** Sat Nov 29, 2008 2:39 pm

BlackLiberty you're the man :wink:

Had the wire in the wrong slot, is the middle one :oops:

mackruss · **Posted:** Sat Nov 29, 2008 2:54 pm

With the pump now fiited, the plunger is nice and firm. Prior to the pump i was pumping about 5 times before the plunger was under pressure. I inspected the fuel heater connector and noticed that it was slightly moist.

If i had a slight leak somewhere presumably in the filter head, will the positively pressurised fuel head now expose where the leak is :?:

The Huco pump i fitted is a diaphragm pump like the Carter. I get a slow pulse from the pump, is this normal for the diaphragm pump versus the Facet that i originally fitted :?:

Lastly i hope, there is no danger i assume of damaging any seals or whatever may exist in the fuel head through to the CP3 pump with the constant pressure from the pump :?:

BlackLibertyCRD · **Posted:** Sat Nov 29, 2008 6:00 pm

mackruss wrote:

With the pump now fiited, the plunger is nice and firm. Prior to the pump i was pumping about 5 times before the plunger was under pressure. I inspected the fuel heater connector and noticed that it was slightly moist.

If i had a slight leak somewhere presumably in the filter head, will the positively pressurised fuel head now expose where the leak is :?:

The Huco pump i fitted is a diaphragm pump like the Carter. I get a slow pulse from the pump, is this normal for the diaphragm pump versus the Facet that i originally fitted :?:

Lastly i hope, there is no danger i assume of damaging any seals or whatever may exist in the fuel head through to the CP3 pump with the constant pressure from the pump :?:

What was happening before is that with the suction part of the CP3 pump and the check valve at the primer pump, the filter head was always under vacuum. When the filter sat overnight in this condition the tiny air bubbles that is usually in diesel fuel separates to the top of the filter head. This causes the fuel heater to overheat and the CP3 pump to suck air. If your fuel heater is damaged, it will leak (spray) diesel fuel. The terminal on the connectors will also be burnt. The fuel filter head will be more trouble free since it now stay full of fuel.

nursecosmo · **Posted:** Mon Dec 01, 2008 12:53 am

mackruss wrote:

If i had a slight leak somewhere presumably in the filter head, will the positively pressurised fuel head now expose where the leak is :?:

If the leak were big enough to "spray" diesel, you would have been sucking so much air before the LP install that the engine would not have run. Diesel has thousands of times more viscosity than air. A hole which allows a slow leak of air into the fuel system will only cause a damp spot at the leak site when trying to "push" diesel through it.

onthehunt · **Posted:** Mon Dec 01, 2008 4:29 am

Quote:

With the pump now fiited, the plunger is nice and firm. Prior to the pump i was pumping about 5 times before the plunger was under pressure. I inspected the fuel heater connector and noticed that it was slightly moist.

You now have found the real problem. Not only do you have a leaking fuel head, the heater maybe damaged as well. Too bad you can't take the pump back and just get a filter head.

mackruss · **Posted:** Mon Dec 01, 2008 5:10 am

onthehunt wrote:

Quote:

With the pump now fiited, the plunger is nice and firm. Prior to the pump i was pumping about 5 times before the plunger was under pressure. I inspected the fuel heater connector and noticed that it was slightly moist.

You now have found the real problem. Not only do you have a leaking fuel head, the heater maybe damaged as well. Too bad you can't take the pump back and just get a filter head.

I'm not sure at what temp the heater kicks in at but i doubt very much that it is working at all as the temp here where i am doesn't drop low enough to cause any problems with the diesel.

I haven't noticed any signs of the connector having burnt only a bit of moisture when removing the heater plug which is something new for my truck. The pump has firmed the plunger nicely and i don't need to pump anymore and worth the peace of mind for around 35 bucks.

BlackLibertyCRD · **Posted:** Mon Dec 01, 2008 7:53 am

Mackruss, don't let some things on here confused you. You added the lift pump, got rid of air in filter problem, so you fixed the problem. If the heater plug leaks fuel (spray fuel) then you replace the fuel head with new and improved. I'm at 60,000 + miles and orginal filter head because I did this fix early.

Fuel Pump Help Please..

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