Bill,
We often ran our tanks low with our old Pro-Jection and never had any
problems related to low tanks. We once had a problem with a pinched fuel
return line on our Pro-Jection which caused the fuel pressure to be too
high for the injectors to be able to open. From what you are saying though
your problem appears to be that there is no fuel reaching the Pro-Jection
at all. In that case, I might take a look at the tank selector valve or
fuel filters. Our original tank selector valve began to stick. It would
work fine for one tank, but it would not switch all the way for the other
tank and would be very restrictive. I would guess that the valve could get
stuck in the middle and be restrictive for both tanks. You could also try
priming the pump by filling it and the lines attached to it with gas before
trying to use it. These high-volume pumps don't seem be able to suck real
well unless they have gas in them.
Here is a list of some things you might try if you haven't already.
1. Run the output of the pump directly into a gas can and bypass all fuel
filters.
2. Disconnect the wiring to the pump.
3. Run 12V directly to the pump (carefully)
4. See if anything comes out (output can be measured in Gallons/Minute if
you time how long it takes to fill five gallon can)
5. If nothing comes out then the problem has to be before the pump.
If proper amount (I think our Pro-Jection manual gave some specs for
this) does come out then it is probably a return line problem or
Pro-Jection problem.
6. Try bypassing the fuel selector valve.
a. remove fuel line of one of the tanks off of the fuel selector valve
b. connect it either directly to the pump or to a barbed hose
connector and another length of hose to the pump
7. Try steps 3 and 4 again.
8. If nothing still comes out then the problem has to be either the line
from the tank or in the tank itself (fuel sock, fuel pickup).
If the proper amount does come out then it is probably a tank selector
valve problem.
If you determine it is the tank selector valve, DO NOT get a replacement
from Gateway unless your '74 is much different from our '73 or they have
changed what they send. The replacement we got from Gateway wasn't even
close to our original. It was much more restrictive and required a totally
different mounting method requiring us to fabricate a bracket. We ended up
tossing it and finding one more suitable for our fuel injection (also does
return line switching) that was worth making brackets for.
Hope this helps,
Zak
>What started with no fuel pressure and towing a few yards with Toyota
>pickup has become more interesting. With about 1/3 tank in the Aux and
>a little under 1/4 in the main tank, I have lost gas pressure to the
>Holley Projection TBI. Drove about 180 miles since fillup. This is a
>1994 version TBI. After changing to a new Holley fuel pump and new
>filter, still no fuel flow from either tank. The new pump would draw
>about 6 in. vacuum on the intake side. Old one only 1 in. Should be
>15 or so gal in the tanks. Can hear pump run.
>
>Do any other Holley users know of a problem of not being able to pump
>gas when the tank gets a little low? Is this normal? Solution?
>
>Bill
>'74 Glacier
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