Happend awhile ago, and being the jack a*s I am I tried to fix it. lets see... about a month ago my fuel pump went out, checked the wires back to the pump no power. so I left it for a few weeks cause I am extremely broke and have class all day. Got the idea I could run a wire from my battery to the pump and just have a switch to turn it on. did that and then my battery died, got a new one and everything looked fine, except for my fuel pump was extremely loud. the way I wired it is I kept the old wires to the pump and just tapped in the new ones from the battery, what is weird is to start the car I have to use the jerry rigged switch, but once im on my way I can turn the switch off and the original wires will kick in, until I slow way down, it seems only when im in a good RPM range does the other wires kick in, anyways I bought a new battery a few days later its dead, dont know if my altenator is out but I think my fuel pump is sucking the life out of the battery, my question is why is it doing that. I do turn the switch off so when its running there is only 12v at a time going to the pump, also why does the other wires kick on when im going above 2,000 RPM, its an external Holley.. any help before I take it in to be fixed would be appreciative, ask any question... I will be prompt..



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1988 Formula 350
Maroon, 5 speed
Edelbrock 750 cfm carb
Edelbrock Performer RPM intake manifold
Hooker super comp. headers
Hookerheaders 3 inch cat-back
3 inch pipe from headers all the way to the muffler
Gutted cat
K&N filter
WS6 Package
ATGI underbody purple neons
Black light interior

 

Help anybody?

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1988 Formula 350
Maroon, 5 speed
Edelbrock 750 cfm carb
Edelbrock Performer RPM intake manifold
Hooker super comp. headers
Hookerheaders 3 inch cat-back
3 inch pipe from headers all the way to the muffler
Gutted cat
K&N filter
WS6 Package
ATGI underbody purple neons
Black light interior

 

well your switch might be diffective , it would also be a better idea to run a straight wire from the fusebox (ignition) to the fuel pump...this would solve the problem since the ignition is on only when the car is running. I don't have any explanation on why it's running on the old wire when your at 2000 rpm .

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LT1 POWERED
HEADMANS HEADERS
NEARLY 300 HP.

EATS MUSTANGS FOR BREAKFAST

 

The best/easiest thing might be to just rewire the FP altogether with a relay switched by the ignition (or toggle switch, whichever you're more comfortable doing).

what did you do with all the ECM stuff after converting to carb ?

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• my Formula Homepage
• Collision P/Ns & Diagrams (Nearly complete now!)

The mind is like a parachute, it only works when its open

 

I didnt convert it to carb, I just got it last summer, it was all done before I got it, I am just learning about cars really so I have no idea how to run a fuel pump relay or anything like that, I did install my own headers and cat-back thats about the extent im up to right now. The way they did it by the looks of me is they just through all the TBI wiring away and just got a whole new fuel devlievery system, by bypassing the intake pump and having an external holley. I wish I knew more about cars but I dont, so any help would be appreciative, and the other wires dont kick on at 2,000 only. They kick on when Im on the highway or driving in 2nd at a good RPM range, im thinking maybe my alternator went out and the pump kicks on with the other wires cause thats the only time the car can get enough power to the pump.. dont know just guessing here..thanks for the help..

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1988 Formula 350
Maroon, 5 speed
Edelbrock 750 cfm carb
Edelbrock Performer RPM intake manifold
Hooker super comp. headers
Hookerheaders 3 inch cat-back
3 inch pipe from headers all the way to the muffler
Gutted cat
K&N filter
WS6 Package
ATGI underbody purple neons
Black light interior

 

How much of the TBI wiring did they remove. From what you describe it sounds as if they used the original FP relay circuit. This would explain the operation under engine speed because the relay is bypassed by the oil pressure switch. I agree with the suggestion of running a completely new relay setup. We can walk you through this if you need help installing. There are several kits that include a relay, the base, all wiring and directions for a reasonable price. If you TBI harness is semi-intact I can walk you through where to find bat and ign power as well as a ground. Then all you have to do is hook up the power wire to the FP and drive away.

John

Heart of Texas Power and Performance

 

When you taped up these wires, you did isolate them correct? Find a friend with a multimeter and test all the lines to make sure nothing is shorted. How do you know the fuel pump OEM switch is working at high rpms?
It was sugested but I would also run a relay from the acc port on the fuse box. It's pretty easy to run the relay BUT I would find out why the OEM wires are all crazy.

 

Im gonna try and clear stuff up... maybe I didnt explain what I did, im sorry guys.. fuel pump stopped working, so I was like oh, must be a fuse or short in the wire, dont know how its setup, dont know anything about fuel relay, all I know is its NOT stock, its commplety redone, since it was a fuel injected and is now a carb. Anyways what I did was just run wires straight from the battery to the 2 wires on the fuel pump also dont ask me why but I left the existing wires that ran the pump on, just in case they kicked on or something.. ok now this is what happend.. Got a new battery, old one was dead anyways. To start up the car I kick on the switch I MADE, which turns the pump on, MY wires are all good no shorts there I made sure... Now once the car is started I can turn my switch off!!!! and the pump still runs cause the old wires are still there.. dont ask me why im all confused as HELL and very upset.. ok also there is more. sometimes when im slowing down and going in first at a low rpm the pump will kick off and I will have to turn the jerry rigged switch I made on, then off again to jump start the old wires.. if this makes sense to ANYONE than you must be *** cause it makes no sense to me, what im thinking is I will just unhook the old wires, leave the ones I made on, take it to a knowladgeable machinc and have them redo my fuel pump wires and screw with the relay and such. im broke and would rather prefere NOT to do this but if it has to be done then it has to be done. also my new battery was dead in 2 days, just another problem in the mix, I HATE GM...

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1988 Formula 350
Maroon, 5 speed
Edelbrock 750 cfm carb
Edelbrock Performer RPM intake manifold
Hooker super comp. headers
Hookerheaders 3 inch cat-back
3 inch pipe from headers all the way to the muffler
Gutted cat
K&N filter
WS6 Package
ATGI underbody purple neons
Black light interior

[This message has been edited by bklucas12 (edited September 27, 2001).]

 

The fuel pump runs on the old wires because the oil pressure switch bypasses the fuel pump relay. The car will not start because there is not enough oil pressure to close the switch and turn the pump on. The car dies because the oil pressure goes down the switch opens and the fuel pump stops pumping.


You can fix this by running a new relay and bypassing/disconnecting all of the old wiring. The easiest way to do this is to buy a kit like the painless 50102. With this kit you get a relay with the base, a circuit breaker, labeled wires and directions. The kit costs 29 dollars shipped to your door.

John

Heart of Texas Power and Performance

 

Damn hotpowerandperf, thank you so much it all makes sense now, The same thing happend before but the oil pressure switch was not plugged in, and my mechanic plugged it in, I cant believe how stupid I was, I looked under the car and the switch is on there there must be a short or something, and im hoping I have good oil pressure, I was scared that It was this huge electrical problem. I have no clue how people become so good at trouble shooting cars I wish I was half as knowladgeble as some of you guys. Im gonna by that kit and wire it up. My only concern is why my oil pressure was dropping, I might just take it in anyways just to make sure everything is alright, thanks for the help again I appreciate it alot....,

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1988 Formula 350
Maroon, 5 speed
Edelbrock 750 cfm carb
Edelbrock Performer RPM intake manifold
Hooker super comp. headers
Hookerheaders 3 inch cat-back
3 inch pipe from headers all the way to the muffler
Gutted cat
K&N filter
WS6 Package
ATGI underbody purple neons
Black light interior

 

you said also you're running 2 wires from the battery to the 2 wires on the fuel pump...one of these is for the tank level gauge. that maybe also a problem.

------------------
LT1 POWERED
HEADMANS HEADERS
NEARLY 300 HP.

EATS MUSTANGS FOR BREAKFAST