26 replies to this topic

[bthotrod]

I have a 302 swapped starquest and I ran a seperate relay for ignition-on and tied that to the fuel pump check wire by the passenger fender well. It seemed to be running fine idling around, however I went for my first test drive and it broke down 3 times with what seemed like fuel starvation. I'm running a walboro 255 and have already replaced it thinking I had a bad one under the assumption it wasn't pumping much fuel at all! I could stop for a second, wait, and it would pump enough fuel to get it going for a while and it would quit again. Would this be due to using the check wire, or a bad grounded fuel pump? I saw there is a ground wire dangling by the rear muffler that looks like it may ground to the tank, not sure if that has anything to do with it.

Thanks!
(I've pulled the fuel line off after the pump before the regulator, and it was just barely pumping out any fuel. Pretty sure it's not a regulator problem)

[croquest87]

How's your tank inside?  Perhaps in tank filter clogged?  Or low voltage to pump . Spinning backwards?

Edited by croquest87, 31 July 2019 - 10:42 AM.

[bthotrod]

Tank has been dropped and cleaned, and I have a fuel filter after the pump that I've pulled and it's also clean. The old fuel pump I took out wasn't full of junk either. I don't think it's spinning backwards, wired correctly and the fuel flow arrow is pointed in the right direction. Could be low voltage to the pump though..

[bthotrod]

I'm pretty sure that I didn't put an in-tank filter on the pickup tube

[croquest87]

Check your voltage for sure to see what you have

[CarlosFley]

I don't know if running it off the check wire by the fender well is a good idea, that could be your culprit

[G54Bstore]

I'd wire in a relay with a new wire right off the battery. That way you know your getting 12+ volts.

[FRO]

There is a factory cone filter that was on the input side of the factory pump, a lot of times the cone filter would get pulled off with the incoming hose and stay inside the hose. worth a check..

[bthotrod]

I have all new 8AN lines from the pickup tube up to the engine & back, no factory lines in place. I do have a relay wired in off the battery, I just feed the wire from the relay into the fuel pump check wire in the engine bay, seemed like a pretty heavy gauge wire.

[81zfan]

I'd put a pressure gauge on it and see what the fuel pressure is doing when it misses.
There is a ground on the stock exhaust at the rear of the car.

Edited by 81zfan, 01 August 2019 - 03:19 PM.

[bthotrod]

What's the ground for? Anything fuel pump related? It is currently not hooked up.
I have a pressure gauge at my regulator, I just don't trust it. It reads 0, sometimes 15, yet I can take the feed line off at the regulator and it is just barely dribbling fuel. It's fluid filled and depending on the heat it can also drop several PSI.

Basically the pump is feeding just enough fuel to keep the car idling, and that's about it... Even with 0 restrictions after the pump and no known restrictions before the pump (pretty sure it has no strainer on the pickup tube). I'm leaning towards some voltage issue, but I don't see how. I'll drop the tank again, check the voltage, and put a beefy ground on it tomorrow or this weekend. Fingers crossed.

[TexasQuest]

The ground on the exhaust is not fuel pump related.

[kev]

What type of regulator?  Hopefully it’s not one of those aeromotive pieces of junk....ask me how I know lol.  

My vote is a bad or dud regulator.   But of course check your voltage to the pump first and buy a darn pressure gauge and put it on that regulator,they’re like $30.  

Kevin

[G54Bstore]

I stopped trying to use walbro pumps a long time ago. After several went bad to quickly I gave up

[81zfan]

THe ground I'm talking about has nothing to do with the pump. It attaches to the exhaust, I thought that may have been what you were seeing hanging down in the rear.
I've had bad luck out of the chinese liquid filled gauges and even some usa liquid filled.
I'd get me a gauge with the electric sensor and put it on the regulator, then you can watch it from inside the car at all times

[bthotrod]

The regulator is a cheap regular with -10an inlet, outlet, and return. I ran 8an lines, which should be plenty. I had to rebuild the regulator myself with a different spring to be able to regulate it down to carb pressure, but for sake of the fuel issue, I have the line removed far before the regulator & the filter and it barely dribbles out fuel. Even still, I have a gauge I hooked inline and a gauge on the regulator, both reading basically no pressure since the issue (but have read fuel pressure when the fuel pump worked at first).

It's a Walboro 255, brand new from a licensed distributor. I also thought it was a dud pump, so I bought another brand new pump and put it in and had the exact same issue.

[bthotrod]

Checked voltage at the pump, it's getting full voltage. Dropped the tank, no strainer on the end (probably should add one) but regardless it means there isn't a restriction. My thought was that maybe it's sucking in some air around the 8an line I made that feeds the pump, so I hotwired the fuel pump and the feed hose stuck into a 5 gallon tank of gas to see if it would pump fuel out. Well, the jumper box sparked, set everything on fire, and made for a fun experience. Nobody got hurt and neither did the pump or my car, but it was interesting...

Anyways before I caught everything on fire sure enough the pump pushed out a pretty significant amount of fuel, nothing like what has been dribbling out of the lines, but then it seemed to slow down like it lost its initial prime and started sucking in air or something. I'm definitely going to re-do that AN line (the first AN line I ever made was the feed line for the fuel pump - smart huh? I could see where the hose wasn't pushed in all the way and could be drawing in air, I was actually able to undo the compression part of the fitting by hand with the line and fitting remaining in-tact. AKA I didn't really crimp down and seal the line like I should have.)

My question now is, would it be a good idea to put a check valve somewhere in the fuel system? I have the high pressure 255 which I've heard doesn't contain a built-in check valve. Not sure how much of an effect that would have.

Edited by bthotrod, 02 August 2019 - 10:56 PM.

[bthotrod]

Hot wired it the right way, pump and pickup tube in the tank, and it will pump fuel out for a few seconds and then it's clearly sucking air.

Pulled the pickup tubes out and since cleaning it my fuel tank has rusted pretty badly.. probably didn't dry it out well enough after cleaning it.

Seems as though the pump is pulling out all the fuel from the inner baffle where the pickup tube is at faster than it refills. Any easy way of cleaning out the lines that feed that inner baffle area?

[croquest87]

I use electrolysis on all rusted items. Did my tank and pickup tubes. POR 15 3 step after. Some time    sodium carbonate(washing soda) car charger and piece of steel bar (for sacrificial rod)  worked beautiful  and years later my tank still looks new inside.

Edited by croquest87, 05 August 2019 - 12:11 PM.

[Indiana]

That wire on the muffler was part of an OEM noise filter wannabe setup and rotted off
For safety issues you should use a pump relay wire from the control relay in the event you crash and the engine is off your wired in relay doesn't continue to pump fuel and kill you in a fire.  (The control relay shuts down without the ignition signal)
That test wire for the pump isn't switched you shouldn't use it for any relay
That pump shoulnd't drain that sump
OEM pump had a check valve screwed on the end of it but it also served as a pre regulator

If the pump is good and the lines aren't mashed and you aren't out of gas then the regulator is junk there's nothing else involved here except your wiring and relay.

Sounds like your regulator is bad and no you can only rely on readings from a liquid filled gauge when its cold; its completely normal for it to change readings when its heated up because of how its made.