Fuel problem again

[osaltyone]

So a couple months ago I was getting the light and it was lean on both banks. I changed the fuel filter to a decent one from Jegs because I thought it was clogged. Fixed the problem for a short drive around the block then fuel cut out and I pushed it home. Changed the fuel pump thinking that was the problem even though it was a new Walboro. Seemed to do the trick, let it run for 30min and a few runs around the block and I thought I was good.

Had to use the truck this morning, so took it out this morning for a real run and it died on me when I stopped at a light and I couldn't get it started.

Had it towed back home. I was thinking maybe it got vapor locked or something, so I hit the schrader on the fuel rail and fuel dripped out, no pressure...I turned the key on and off a few times checking at the schrader and didn't seem to have a lot of pressure. Hit the key a few more times without starting and Wham it started and runs fine now.

Any ideas on why I would see this odd issue? I haven't really driven it too much before this because I did not want to break down.

[Wasted Income]

Could be the fuel pressure regulator, allowing rail pressure to bleed off to the tank. That is of course, assuming you're running a truck style return system.

Also, is the tank vented? If not, pull the cap off and take it for a ride to see if that solves the problem.

[osaltyone]

I can replace the regulator on the rail to see if that helps. The tank does has a vent hose on it. I have tried to start the truck when the issue is going on with the cap off and no luck.

[Wasted Income]

If the rail won't hold pressure, I'd say it's a regulator. Put a pressure gauge on the schrader valve (pull the core out first) and make sure it's even getting up to full pressure, to ensure it's not a restriction on the supply side.

[74project]

Ive had the same problem...i switch during the swap to a returnless style but did not change the fuel rail and kept the regulator still hooked up to the manifold. My truck would drive fine then completely out of the blue die out...the only way it would restart was if i capped the manifold and fuel regulator on the fuel rail then for some reason it would start back up and has been running great ever since. I did have to adjust my ecm to lower fuel pressure which was causing it to run rich. Hope it helps..
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[osaltyone]

New regulator did not help. Today it seemed to happen Just before I got up to temp. I got it back in the garage by putting it in park just as it was about to die, then rev'd it a bit which got it going again and pulled it in the garage. Going to go rent a pressure gauge from autozone now...
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[osaltyone]

Fuel test gauge shows 48 on first start then once warmed up 50. When I put it in drive, hold the brake and give it has I get up to 60. No codes now, but looks like it threw p0171 & p0174 earlier. Probably when it was dieing.
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[osaltyone]

would it matter that my VSS is not hooked up yet? I have the dakota digital guages, just haven't wired them yet. I thought it was just to tell the pcm when I am slowing down, but throwing things out there. Maybe I will take video of my fuel system to show everyone. Maybe I did somethign wrong in the mix... #learning



The suction is just my intake...

[Wasted Income]

Key on / engine off should be ~ 55-62 psi

Engine running at idle with the vacuum line hooked up to the regulator should be ~52 psi

Engine running at idle without the vacuum line hooked up should be 58-60 psi.

No, you don't need the VSS hooked up for the engine to run correctly. I say this after personally completing and tuning several LS swaps on vehicles with manual transmissions, and vehicles with NO transmissions at all

Good luck.

[osaltyone]

Originally Posted by Wasted Income

Key on / engine off should be ~ 55-62 psi

Engine running at idle with the vacuum line hooked up to the regulator should be ~52 psi

Engine running at idle without the vacuum line hooked up should be 58-60 psi.

No, you don't need the VSS hooked up for the engine to run correctly. I say this after personally completing and tuning several LS swaps on vehicles with manual transmissions, and vehicles with NO transmissions at all

Good luck.

Thanks, now I just have to figure out why I am not getting the pressure I should be out of the walboro pumps.
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[Wasted Income]

I had a walbro pump take a crap on me...the truck wouldn't idle for crap...had to 2 foot it in traffic, etc.

Went to a Bosch 044 and never looked back.

[osaltyone]

Originally Posted by Wasted Income

I had a walbro pump take a crap on me...the truck wouldn't idle for crap...had to 2 foot it in traffic, etc.

Went to a Bosch 044 and never looked back.

This is my 2nd Walboro pump, seems odd that it would be 2 faulty pumps.

Is it possible I have an air pocket or something? I don't see how it is being restricted, other than the fuel has to travel over my step notch.

Fuel tank is in the rear, port on the bottom, so it has to be sucked up 9" or more from the rear port to the top of the notch.
Here are some pics during my build.



from the fuel pump it is hard line to the front, then the fuel filter, off the fuel filter fuel injeciton host up to the rail. That piece of hose is covered by 1" fire sleeve to protect it from exhaust, trans and engine heat.

[Wasted Income]

That is definitely not the ideal setup. Would be much better if you could have the pump PUSHING the fuel up over that notch, vs. it having to SUCK it out of the tank, and then up and over. That is also a lot of 90* bends...that also adds restriction to an already tough situation for that pump.

[osaltyone]

I don't see a way I can install the pump without sucking up from the bottom port to the frame at minimum. I'd have to see if I can fit the pump near the side of the tank.

[High ho silverado]

That pump is above the tank pretty much, in my experiance with external pumps if they are not below the tank they air lock, and pulling them over the axle like that doesn't help, we had a holly black pump that would do it too, areomotive has a pump that claims to be able to pull and push no matter were u put it they also make a pretty slick intank unit that would deffinatly do the trick but its all in how much a guy is willing to spend, lol. I personally will never buy another walbro pump again, had lots of problems with them, jus my two cents. Hope u get it fixed, I hate to see a beautiful machine like that sitting in traffic.
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[68GMCCustom]

mount that pump closer to the tank. here's my setup also with a walbro...vette reg is on the inside. may not be the ideal setup.....but its been feeding 500+hp LSx w/o issue.

[osaltyone]

Originally Posted by 68GMCCustom

mount that pump closer to the tank. here's my setup also with a walbro...vette reg is on the inside. may not be the ideal setup.....but its been feeding 500+hp LSx w/o issue.

Yea, I was trying to copy yours when I first saw it, but my airbag and cantilever setup runs all the way back along the outside frame. I might be able to mount it on the bottom of the frame in the area where your tank bolts through the frame. Looks like your tank is similar to mine.
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[osaltyone]

As yo can see it is in the way.



But I was thinking about mounting it here with the feed fromt the tank toward the front of the truck, loop the feed to the rail around to the inside of the frame up to the notch. Do you think that will work? Wonder how everyone else with a step notch is doing it. I can remove the hard line over the notch, but did not like the rubber hose when I had it running there before.

[68GMCCustom]

That's where I'd put it. there's a BIG difference between it being fed from there VS where you had it before. These pumps are designed to push...they don't pull so well.

Another choice would be drop the tank and mount and internal. Mine's a Boyd's tank. They do them in efi too....but my build was carb'd so when I bought I didn't get the efi option. Now I wish it were in the tank...but at least its easier to service this way!

[osaltyone]

Originally Posted by 68GMCCustom

That's where I'd put it. there's a BIG difference between it being fed from there VS where you had it before. These pumps are designed to push...they don't pull so well.

Another choice would be drop the tank and mount and internal. Mine's a Boyd's tank. They do them in efi too....but my build was carb'd so when I bought I didn't get the efi option. Now I wish it were in the tank...but at least its easier to service this way!

I will try and see. Thanks! The tank is a Brothers tank, so I am not sure on my in tank options. It was like yours originally carb, until I got the itch to tear it apart and do the 5.3.
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[awhite4557]

Another option is to mount an internal pump in your tank. Tanks Inc. sells one that might work, here is the link http://www.tanksinc.com/index.cfm/pa...prod/prd84.htm
This set up uses a walbro pump.