ok, now that i have replaced my high pressure in line pump with a holley red pump, the in tank pumps wont spin. so the holley cant suck fuel that far and it wont run. do i need to hard wire the in tank pumps to a run/start on the ignition switch? this is really getting to be a pita....had this thing for a month, still doesnt run, and the other day my daily driver broke.....any help would be much appreciated.

mike

 

oh, btw....its an 89 with a carbed motor in its place(was efi)...if that clears anything up....thanks


mike

 

You will have to check but, I think that the gas a diesel engines used the same tanks during that body style. If so you could install diesel sending units, which will not have the electric pump attached to them. This will provide an unrestricted flow to the Holley pump.

I just got my 460 going last week and I am using the Holley Blue pump. My truck (1991) was a diesel and the tanks are working fine.

The only complaint I have is the brand new fuel pump started leaking and had to replace the base gasket. I should have known that if it said Holley on the side of it it would probaly leak.

Brian:-)

 

hey brian, how far up did you mount the blue pump? i mounted mine where the stock in line high pressure pump was, and i dont know that the holley could pull fuel that far. thanks for your earlier input.


mike

 

Find the Green fuel pump relay, probably under the hood. Unplug it, Take a meter and check for continuity to ground, see which of the smaller 2 wires is the groung, then the other small one should be the hot from the ECM to pull in the relay. Wire from a key-on only source, such as the blower motor fuse, to the small tigger wire to the relay. Then plug the relay back in, turn the key on for about a minute and see if you get any fuel.

Occasionally the ECM sends the ground instead of 12 volts( 12 is always there, but ECM grounds it to complete the circuit) but I have usually seen this on Generic Motors cars.

 

[updated:LAST EDITED ON 21-Aug-02 AT 02:17 AM (EST)]First of all fuel pumps are meant to pump, not suck, so the closer you move it to the fuel source the better. As far as the in tank pump(s), there are two ways of dealing with them. The best method would be to pull out the pump/ sender assembly, and extend the fuel pickup pipe to the bottom of the tank, thus eliminating the in tank pump.

If you decide to keep the in tank pump(s), you need a method of turning them on. In EFI applications the PCM grounds the fuel pump relay, which then sends power to the pumps. The PCM only turns on the pumps if the key is switched on (for about 5 seconds), or if there is an RPM signal from the distributor it keeps the pumps on. This is mainly for safety.

So if you run ign. power to your fuel pump relay, and ground out the other side on the relay windings, your in tank pump will turn on with the ignition. However this will control only one pump I think, Idon't have the wiring diagram in front of me. Keep in mind if you do this and you get into an accident that causes a fuel leak, the fuel wont stop until you switch the key off.

I know it sounds complicated, but if you get a wiring diagram and study it, it is actually a lot simpler. Good luck!!

Nick from the frozen north
1974 F-250 4X4
soon to be 429
dana 60 front and rear

 

ok got the in tank fuel pumps workin by grounding the relay, but now the damn fuel pressure regulator wont hold it to more than 4.5 psi. this is really becoming quite irritating. before i installed the holley red pump, the regulator wouldnt hold it below 15 psi, now that i have a low pressure pump, it wont keep it above 4.5. and with no regulator, its runnin 12 psi(must be the in tank pumps....i'm thinkin about lookin into getting some in tank pumps from an 86 f350 with the HOT FUEL option(my haynes manual says something about it). whatever, i know im rambling, im just mad i guess. thanks for the help guys.


mike

 

See, other post. Get a on the frame fuel pump for an 85 F250 w/460 and that should cure it. They ran with the key on all of the time with no EEC to bother with. Since you have already taken care of the relay problem, the 85 pump should cure your ailments.