Aftermarket fuel pump

[gtobrett]

I race an '89 Grand Am with a DOHC Quad4. Our rules have changed for the coming season and I'm forced to install a fuel cell and aftermarket electric fuel pump. I have the new pump and cell installed and now it just cranks over....doesn't even sound like it's attempting to start. The fuel pump is pumping gas out of the cell, but I'm not sure how to tell if it's getting to the fuel rail. I'm also wondering if by taking out the old gas tank (and with it the fuel pump and sending unit), if I've upset the PCM to the point where it won't allow the car to start.

I'm completely new to the Quad4 maybe it's something simple, but I'm stumped!!

Any thoughts would be greatly appreciated!!

[BadBoy]

things to check:

- does the new pump match the old pumps flow? i don't think the injectors will work with too low of pressure, same w/ too high.

- i'm not trying to insult, but did you hook the fuel lines up right? the pump isn't going to the return line? is the return line hooked up? that will cause probs.

the old wiring from the old pump could be a prob, don't know for sure tho. maybe try running some wires from the stock harness to the new pump and see what happens. the fuel gague wires shouldn't matter.

there is a port on the fuel pressure regulator on the fuel rail to measure fuel pressure.

i'll post if i can think of anything else.

BadBoy :glasses:

[gtobrett]

The new pump is a small 2-3.5 PSI unit. I'm not sure how that matches up with the factory pump output. The old pump wiring wouldn't push the new pump because it didn't carry 12 volts so I wired the new pump to another 12 volt switched source.

I assume that I've connected to the correct fuel line. I'm using the largest of the three lines that were going to the old tank. I don't have the return lines connected up yet.

[BadBoy]

gotta hook up the return line- it won't work w/out it. stock pressure is:
2.3L engine: 41–47 psi (280–325 kPa)

hope this helps!

BadBoy :glasses:

[Colin]

Originally posted by gtobrett
The new pump is a small 2-3.5 PSI unit. I'm not sure how that matches up with the factory pump output. That's a carb fuel pressure . Fuel injection is much higher , the injectors won't operate @ that pressure . ;)

[gtobrett]

I figured out the pressure problem and have dumped the aftermarket pump. I removed the stock pump from the gas tank and hooked it up as an external electric pump. It seems to be starting ok now, but it does look like I need to get the return line hooked up because while it will start and idle ok, it wants to die if I give it any throttle at all.

[rixGAphx]

You REALLY need to go with an aftermarket, out-of-tank FI pump.

The in-the-tank models are not only designed to be gas-tight/sparkless, but the surrounding fuel is part of what cools them (not just the fuel flowing thru them).

Out-of-tank pumps are designed differently, intended to be cooled by ambient air and flowing fuel.
And, they integrated pressure relief, not dependent on return lines.
Check with your racing orgs specs, they might not ALLOW return lines because of the added fire potential in a crash.

I don't believe any racing org allows the fuel pump to be within the driver compartment.
An out-of-tank pump is sturdy enough for exterior mounting.
I don't know about the pump from your '88's tank, but the collection of metal and plastic that was the old in-tank pump in my '96 sure isn't durable enough for exterior mounting.

Finally, the operating system on the '88 was OBD-I, which is pretty dumb and simple.
Nearly any wiring problems or codes can be worked around with either jumper leads or a couple resistors.

Good luck.
-Rick