Fuel pump problems.

[canadian]

The truck has been sitting for a number of years but has always been started every once in a while to make sure everything stayed lubed. I took it for a ride up the street a few weeks ago and noticed that the fuel pressure would fluctuate a lot. Turning off the key, the pressure would drop right away so I started with the easy things first. I replaced the fuel pressure regulator and had the same problem so I knew it was in the tank.

It got to the point where turning on the key, the pump would prime but I would get no pressure at the rail. I could hear the fuel dripping in the tank so I knew there was a problem in the tank. I dropped the tank and took out the pickup assembly and found that the hose between the pump and pickup had rotted away and turned into goo.

I replaced that hose with a new one from AutoZone and made sure that everything was fine before bolting everything back in. Several days later I turned they key and got nothing. No primp, no fuel pressure, nothing at all, so I figured the pump was dead. I get 12 volts all the way to the pump harness on the tank so I thought it was the pump. I ordered a new pump and dropped the tank again.

After getting the new pump installed, it worked fine. I started it a few days ago and it ran fine and held pressure. After turning off the key I did notice that the pump ran for about 10 seconds which I thought was odd but attributed it to the Racetronix harness. Today I attempt to move the truck so I can clean the garage and the pump is dead again. Turn the key and I don't get anything. I've jumped the connector on the firewall and I don't get anything either. I get 12 volts down to the power connector going to the sending unit, so I can rule that out.

The only thing I can think is that the wiring on the sender is shorting out or the brand new Walboro is dead already which I find hard to believe, but stranger things have happened. Does anybody have any other ideas? I'll be dropping the tank again tonight and pulling the sending unit out of the tank to see if I get 12 volts to the pump connector on the inside of the tank and also testing the pump.

Any other thoughts?

 

[leroy]

Re: Fuel pump problems.

You probably checked the ground on the rear bumper support, but I will remind you anyway.

Jim

 

[canadian]

Re: Fuel pump problems.

You probably checked the ground on the rear bumper support, but I will remind you anyway.

Jim

I do know that the ground screw back is attached, but I thought it was only for the tail lights? My understanding is that there is a set of feed wires coming back to the sending unit (one black / on gray), then from the sending unit itself there is a ground stap that connects to the frame just in front of one of the bed body mounts in the rear (right above where the 4 bolts are that hold the fuel tank strap). Other than that, I didn't think there was any other wiring to look at.

***EDIT***

cleaned and re-installed ground wire above rear driver side shackle and still nothing. going to drop the tank.

 

[SY2932]

Re: Fuel pump problems.

You probably checked the ground on the rear bumper support, but I will remind you anyway.

Jim

Yep, I would suspect a ground issue that this point. When I redid the sending unit wiring on my old daily driver S10, the ground coming off the sending unit *looked* good until I gave it a little test tug and it busted clean off... Applying 12 volts directly to the plug on the sending unit will rule out a problem in the wiring. Even if the ECMB fuse was blown, the test connector by the firewall should have still made the pump run.

With regards to the fuel line, did you get line that is spec SAE J30R10 and can be IMMERSED in gasoline? If not, it won't last. SAE J30R9 which is for inline use is only meant to have gasoline on the *inside* NOT the outside. Ron Gregory makes mention of it on his webpage in the "installl tips" section.

 

[canadian]

Re: Fuel pump problems.

30 minutes later and the tank is dropped, although I don't have the motivation to continue with it tonight. Tomorrow I will continue to troubleshoot. As for the fuel line hose, the first one I don't believe was rated to be submerged in gas based on the rot I saw and the ball of goop it turned into after removing it. The image below is of the old Walboro pump that came out of the truck. The rubber line is what came with the pump, although I didn't buy it from a SyTy vendor so it may have been designed for external use.



The replacement hose I used on this pump was from AutoZone and is stamped J30R9 which according to the page won't work. I bought this Walboro fuel pump from RaceProvenMotors and I would assume that the hose that came with it will work when submerged, otherwise everybody would be having problems with the hose falling apart.

The only markings on the hose are EFM-EFI 18519. I'll be using that tomorrow to attach the pump to the pickup. I agree that there is a gound issue somewhere, although all the lines appear to be good. I may just replace the sending unit for peace of mind.

So the question now is if the hose that comes with a SyTy/Buick Walboro pump is rated to be submerged in gas? I have to believe it is based on the number in use and lack of failures.

 

[SY2932]

Re: Fuel pump problems.

So the question now is if the hose that comes with a SyTy/Buick Walboro pump is rated to be submerged in gas? I have to believe it is based on the number in use and lack of failures.

Ugh, that fuel line is UGLY. Get into some high boost and not be quick enough to get off the gas and that could have costed you a motor . Any reputable vendor syty or otherwise, knows that the fuel pump is in the tank. I think any problems with the fuel line issue are a result of ignorance on the resellers part. They resell pumps not aware that you can't just use any fuel line (if they include it with their kits) it has to be resistant to gas on both the inside and outside.

 

[canadian]

Re: Fuel pump problems.

No need to worry about the motor since the truck has been in the garage for 6 years. I finally have the motivation to drive it again and was taking it for a slow test drive up the street when I noticed that, so there was little to no boost.

Like I said, I think this hose will be fine in the tank. I just have to find the wiring problem since everything on the sender looks fine at first glance.

 

[TYTILIDIE]

Re: Fuel pump problems.

I hate to say it but I have had that piece of fuel line look like that and it came with the Walbro. Best bet is to go get true submersible blue fuel line. So far it is all that has worked for me. I had this problem several times a few years ago. The line I bought cost me $20 a foot.

 

[Foot Performance]

Re: Fuel pump problems.

I hate to say it but I have had that piece of fuel line look like that and it came with the Walbro. Best bet is to go get true submersible blue fuel line. So far it is all that has worked for me. I had this problem several times a few years ago. The line I bought cost me $20 a foot.

Do you know where you can get that and/or have a part number

But I have seen that hose bust out alot pritty comen problem on stock vehicles especially one older GM :tup:

 

[canadian]

Re: Fuel pump problems.

I ended up ordering some fuel pump hose and other parts from Ron Gregory over at http://www.autoperformanceengineering.com which should be here this week. Instead of trying to trace down any wiring issues with the sender I checked AutoZone and out of the 5 near me, one had a replacement so I just spent the $55 to replace it.

One additional reason I replaced the sender is that the gas gauge started having a mind of it's own where it would swing from empty to full and back again. Sometimes it would read 3/4 of a tank when I *knew* there was only a few gallons in it, so that was another reason I wanted to just get a new one instead of farting around with this one.

Still going to make sure that I get power to the pump connector inside the tank before putting everything back in so I don't have to pull the tank again.

 

[Daryl H]

Re: Fuel pump problems.

I suggest you change out the fuel filter also.
In the event that it may have caused your first fuel pump to die, then your second....,
changing out the filter might save you a third one.

 

[canadian]

Re: Fuel pump problems.

I just might do that, although the issue is that the truck has been sitting instead of driving. The fuel filter probably has had about 1 gallon of fuel through it (if that). The first tank drop was to fix the hose because it was obviously not rated to be submerged in fuel/fumes. The second time the tank was dropped was because I thought the pump was dead, but after having the same problem with the replacement pump I believe the issue is with the sender, not the pumps.

I have been trying to clean the garage at night, but I only get about an hour of free time to do anything at night so I haven't gotten back on the truck. I should be getting some replacement fuel hose today so I will be ready to swap everything out. Hopefully this weekend I'll have time to get back on it.

 

[Merk]

Re: Fuel pump problems.

dude, swap out that pump screen too! It looks hideous. I have a new GM one I'll give you. PM me your address.

EDIT: I'm sending it down with Adam.

 

[canadian]

Re: Fuel pump problems.

Thanks Merk! That's the old one that got tossed in the garbage, although I'm almost 100% certain that it was a perfectly working pump.

I have a new pump and pickup that's in there now. My order from APE arrived today and looking at the markings on the fuel pump line from Ron that's specifically designed to be put in fuel, it's the same number that comes with the Walboro pump from Race Proven Motors (or whatever it's called now).

So, this weeken I'll end up putting everything back in the truck (hopefully for the last time).

 

[canadian]

Re: Fuel pump problems.

I never thought that this truck would drive me to drink, but it's getting damn close. I took the old sending unit out and hooked it up to just the wiring and I do get 12 volts at the pump connector so I took the pump and hooked it up to 12 volts and it runs fine (it should since it's new), so I don't know what the deal is. I bought a new sending unit so I put that in and slid back under the truck to get everything buttoned up.

After hooking everything up and bolting the tank back in, I look down to see an o-ring lying on the floor....
There were a number of words said that can't be displayed on this website after I realized that the o-ring for the return line had fallen off. Back down the tank comes and I have to take the lines off to make sure I didn't lose the other one either.

Finally get it back in and it has pressure every time I turn the key. Wonder how long this will last?