So I had my escalade idling in the driveway on a slight slope. All of the sudden it died and I immediately knew it was the pump. About 3 or 4 months ago I dropped the tank with the intention of installing a Walbro 450 lph, I ended up returning the Walbro 450 because I just couldn't see a good way to mod the stock stuff to fit it in and I was really concerned about the stock siphon jet pump that supposedly keeps it from running out of fuel at lower tank levels. When I was pulling out the old factory pump, it was rusted so bad I ended up breaking the top hose connection barb things off of it. After researching as much as I could, I came to the conclusion there's not much hope if you want a drop in higher flow fuel pump that leaves the siphon jet pump thing working like stock. I couldn't afford to have the truck down while I ordered parts or tried to salvage the junkyard for a cheaper used one. So I went to the local parts place and bought a brand new Delphi for $350.

But I did something really stupid and took it apart, it was a different design than my original factory pump, I was hoping I would find a way to put the walbro 450 in place of the Delphi pump, but in doing this I broke the tab clip that holds the inlet and outlet hoses to the jet pump thing:


I wired it up like this and put some zip ties to try to hold it in place, I really didn't want to have to spend more on another pump. This worked for a few months up until now when it seem to quit while idling in the driveway. So I blew another $350 on another brand new pump and put it in, I would have tried to order a cheaper one from rockauto, or tried to find one at the junkyard, but I can't afford to have the truck sitting there and I need to use it.

So the big question, is there anything I can do with this almost good pump? It appears to be the newest OEM redesign, I wish I could have put the pump in this one into the new one I just bought and made a stock dual fuel pump, I just don't see that working since I think it would have to run a line through the jet pump? The pump is a Delphi FG0808 or DFG0808, I'm not sure the difference in this Delphi unit and the stock GM one, or the AC Delco one.

 

Is that a flex fuel pump? I also bought a stock replacement Delphi pump for a 2013 flex fuel denali. I would save the pump, if it is flex fuel it puts out some good flow. Also, it has the extra small outlet for the venturi, so down the road you may be able to rig up a dual pump kit using that one and any other pump. Then, even if the 2nd one is aftermarket, you have the venturi fill covered!

The assembly p/n I bought was FG1054, but the pump itself had the following numbers:
3380 16119 1
0908

Trying to fit a 450 in it. Yes it is a pain. Got it assembled but am having troubles with leaks at the Tee placed in there to feed the venturi, which is about a 3/16 hose. Cannot find that hose size in PTFE so am trying to reuse the stock hose.

Wish I got pictures of it inside the bucket. Basically I took a piece of stainless sheet steel, put a curve in it to match the radius of the pump's holder. Then I bent it at a 90 to support the bottom of the pump, and attempted to tack weld 2 stainless hose clamps to it; one clamp goes around the plastic housing that holds the pump, and the other goes around the fat end of the pump to keep it from rotating. Had to do some minor trimming here and there on the bucket, also had to be cautious to where the hose clamp screws were positioned so it would all fit back into the bucket. I used Walbro's pump sock, which you also have to pay attention to the orientation of the pump.

Ordering a Tee with more aggressive barbs hoping that will help it to seal. Started out with screw drive injection clamps, they leaked. Installed crimp clamps, leaked but not as bad. I am bench testing in a bucket, luckily, before pulling the tank to install. Doesn't seem to leak until I approach around 60 psi, then it mists at the Tee connections. The goofy looking hose going to the venturi was my attempt to put on some ptfe shrink tube over the hose to protect from chafing if it moved around on me. It didn't shrink down so well...


Finished assembly with Walbro 450



Stock Delphi pump assembly with bucket removed. Still has stock pump. Markups show what was done to hold Walbro (no pics, sorry!)

 

I put a new Tee on this thing, along with new hoses as the other ones had imprints from the clamps and I was afraid they would not reseal. Ran it in a bucket at 100% duty cycle and slammed the valve open and shut on my test rig, no other leaks. Peaked around 90 psi and just under 20 amps. If there was any restriction in the line (read: building any pressure at all), the bucket stayed full at every setting.

Did some testing with a stopwatch, power supply, dc motor controller (21 khz) and a gallon jug, here is what I got. All tests were done at 15v, as my logs show the FPCM seems to always register 14.5-15v anyways. Hope my calculations are correct.

Duty cycle 38% - 45 psi - 1 gal/17 min (22 lbs/hr or 13 lph)
Duty cycle 59% - 58 psi - 1 gal/80 sec (281 lbs/hr or 170 lph)
Duty cycle 100% - 75 psi - 1 gal/46 sec (489 lbs/hr or 296 lph)

The pump didn't seem to want to run under 35-38% duty cycle with any restriction in the line. This happened when dead-heading it or restricting it to get it up to around 43-45 psi. The pump speed would sound like it jumped up and pressure would drop 10+ lbs for a sec, then recover. Almost like there was air in the system but I don't believe there was, as it would do it even after a fire hose run. I don't know what to think about this, but my stock cal has a Min duty cycle for the pump and it goes as low as 18% at 15v and 300 kpa (43 psi), with an absolute Min DC of 10%. I could set the cal at this higher duty cycle but now am concerned that I may not be able to turn the fuel down enough for idle/decel. 72 lb injectors are already down to the low 1.?? ms at idle at 300 kpa.

Keep in mind this doesn't include the restrictions in the rest of the truck's fuel system, it is only right out of the pump.

 

I know I really messed up and should at least of tried to buy a flex fuel pump and bucket from a L59 Tahoe. I would think all the tank holes and stuff are about the same size so I wouldn't see any issues installing it? From some different sources it appears the stock pump I put in supposedly is only like 60-80 lph. I know everyone likes to bash boost a pumps, but I don't see why they wouldn't work, it seems like we've got room to run a lot more voltage on the motor to get some more flow. I am still basically stock, so I don't technically need the flow yet and I just wanted the truck back up and running again.

Do you need any parts off my old one I can send you?