1987 GMQ / Mods Soon / Fuel Pump Ideas

[Forcus]

Hey guys,

Researched some other threads and here is what I "know":

- My car has a separate fuel pump and sending unit
- The Mustang upgrade pumps only work with a "spacer" (radiator hose can be used but I question whether fuel would deteriorate it)
- There does not appear to be a good new sending unit replacement for my car

Issues:
- Partial fuel pump failure. I think one of the vanes is sticking. Only manages 20-23 PSI and it bleeds down to 0 (engine off) in less than 30 seconds. Already replaced FPR. Also the low fuel light is on however there are less than 3 gallons in the car so I am not absolutely sure the sending unit is bad. Also the fuel gauge appears to be working (I don't know if the light is integral to the sender - that is, either both work or neither work).

My car is currently stock. Over the winter I plan on taking it to at least base H.O. level. Within a year or two I plan on a turbo setup, or a used supercharger setup in the meantime. I'd like the fuel pump I install to at least be able to handle H.O. / H.O. with a few additional mods. I'd really like if the upgrade I do now is sufficient for the future setup but that is not a priority.

Any ideas? Would like to order a pump this weekend.

[sly]

already replace the fuel filter? The stock replacement pumps will handle a stock HO no problem and a mild build with ease. I know others have done the skinny pump replacement of the stock pump in the hanger and filled the gap with something, but I don't remember what. The low fuel light works off the sender's signal just like the gauge does. The sending units rarely fail intermittent. That's usually a wiring issue (the plug not making good contact on the sending unit's prongs). That's an easy fix though. Also, there a chassis ground near all that mess and sometimes that gets loose and can cause all kinds of fuel issues. It's worth a check.

[gadget73]

you can use a hose clamp to retain the Mustang pump. Put a slice in each side of the stock sock to pass the clamp through, and use that to hold it to the metal part of the hanger. I would not use radiator hose. Its probably not fuel-compatible rubber. If you don't want to clamp it, then using pieces of regular fuel hose spaced around the smaller pump to take up the slack would be a good option as well. Probably 2 or 3 pieces of 1/4" hose would be plenty to make the pump sit in there tightly.



but yeah, most of the time the pumps work or they do not. A crack in the hose between the pump and the plate will cause the same symptom you have too. Thing is though, if you're pulling the hanger to fix that, you may as well swap the pump.

[VicCrownVic]

...
A crack in the hose between the pump and the plate will cause the same symptom you have too. Thing is though, if you're pulling the hanger to fix that, you may as well swap the pump.

I had that happen on my 91 when I first got it. The pump still worked fine but since I was going in that far to fix the hose I replaced the pump as well.
The hanger assembly also needed to be replaced due to excessive rust, although the tank had no rust on it. (I guess the hanger and the tank must be made of slightly different metals.) So I ended up getting the hanger and pump as one kit.

[gadget73]

I had the opposite problem. The tank sprung a leak, so it had to come out. Hanger and pump were fine, but it was pushing 25 years old at that point with somewhere around 180k. I put a new pump in with the tank. I figured my luck, the pump would have failed about a month later, probably at the gas station immediately after a fillup.

[Forcus]

Thanks for the help guys. I am going to get the tank out tomorrow and see what I have. A split "feeder" hose from the pump to the top of the hanger does sound plausible.

[packman]

I used a NAPA part# 8104 for the filler hose/hanger. This is what I did....

http://www.grandmarq.net/vb/showthread.php?49198-Fuel-Pump-Upgrade

Packman

[Forcus]

OK, got the tank out, no sign of a split in the feeder hose. I think I've ruled out everything else - new FPR, had injectors cleaned and checked to make sure one wasn't sticking open, filter was changed not too long ago (and wouldn't account for the bleed down in pressure anyways). The hanger looked in really good condition except the rubber "cone" which was hardened and had some cracks. Wish I could just get the cone but from what I saw they don't even swell the hanger and pump separate.

[Forcus]

Ordered a 190 lph Walbro fuel pump from Brothers Performance for only $90 shipped. 155 lph would have been perfectly fine but was actually more expensive. Quick reading, couldn't find any good reason not to go bigger, and 190 lph is supposed to be good in to the 400 HP range. Might try the radiator hose spacer setup but am a little concerned that its not fuel resistant so while I wait, might think of something else I can try (or figure out if the radiator hose will hold up).

EDIT:

Got an idea from the Factory Five forums, look for a filler neck hose. For obvious reasons should be fuel resistant (although immersion in fuel 24/7 is a little different). I'll probably try it after I get the pump and take some measurements.

http://www.napaonline.com/Catalog/Result.aspx?Ntt%3dfuel%2bfiller%2bhose%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3dfuel%2bfiller%2bhose%26Dk%3d1%26Dp%3d3%26N%3d0