ok guys i have serched this but u can't really get a 100% answer. ok well i am puttin in my 350 carbed engine in place of my 305 tbi engine and i have everythign to do it, all i need to know is how to wire the fuel pump to run without the computer. alot of people say leave the computer and don't cut any wires and just tuck it all away. Well i would liek to do it the rigth way and not have to leave it. i wunt to take out the harnes and the computer. ok well does anyone know 110% how to wire the pump up? i really need to know and them wireing diagrams are just to confuseing to me. also if i takew out my computer my tail light and headlight and everythign will work right?

 

Pull up the carpet at the back of the trans tunnel between the two rear seats. There should be a plastic piece with 4 wires coming out of it. The tan&white wire is for the fuel pump. Connect this wire to a hot ign source that can be found on your fuse block. This way the fuel pump will always run when the key is on. Make sure to use an inline fuse when wiring. You also need to regulate the fuel pressure. I assume you have the hardware for that.

 

I personally would not want a fuel pump that ran all the time the key was on. Better to wire it through an low oil pressure switch. Use a gm# 25037045 switch (if there isn't one already there)threaded into the hole above the oil filter. Wire from the ignition hot to one of the switch terminals the other terminal to the tan wire descibed above.

 

wait doesn;t the fuel pump have to run all the time while the key is on?? also if i hooked it up to an oil pressure switch then i would have to crank the engine over to the oil pressure raised be4 it would dtart right?? ATOMonkey i just run cut this wire and run it to a spot on the fuse panel where i only get power when the key is on right? also how do i get it to stay in the panel just jam it lol. and for the inline fuse wut amp should i get and were can i buy a fuse block for it. sorry about the quections but i just have one more, should i ground somthing or is it just this one wire i mess with and i can tear all the wires under the hood out? cause wut i heard was u have to run liek 6 diff wires to get it to work thanks so much guys

 

I wired mine to a switch, but the ignition switch is the same thing. Only reason I didn't do it was because the car was really pissing me off at the time. Anyway, the fuel pump is already grounded so supplying a 14V source to it will complete the circuit. As far as getting the power to it, I used a male spade connector in the fuse block on the port labeled ign. There is also a spot called radio and bat, that are also power sources, but run off of different circuits. Just cut the wire and be sure to leave plenty plenty of wire to work with. You'll have to use a length of 12 gage to complete the job. I recomend soldering them together since you don't want this to come apart driving down the road. If you want to get ign voltage from somewhere else you need to patiently patiently patiently patiently study the wiring diagrams. You might want to do this before you start just to make sure I'm right. I'm going off of memory right now. They are online and you can find links to them if you use the search button and the keyword wiring diagram. They are much much better than the junk Haynes diagrams. The wires in the engine bay are used for sensors/gauges and lights and such things too, so be very careful what you remove. Later

 

ok well i decided to go out and tear aprt my car to get to the wires under the seat cause i had to clean it up and hide my amp wires so njo biggy. well i cut the tan and white wire and hooked it up to some wire and ran it into the fuse panel on an open thing that was only on when the ignition was on. well it started rigth up no prob. i also unhooked it just to make sure i had it rigth and it just cranked. ok well wut wire is the ground so i can cut the fuel pump realy out under the hood?? do i just need a power and a ground for it to work? thanks

 

sum1 please reply lol, i started the swap and i need to know soon. if run the tand a white wire from under the carpet to the fusepanel can i take the relay out under the hood or no? also wut do all them wires do back there so i can just hook them up the way i wunt ? thanks

 

Why would you want to get rid of the relay?

 

well it seems like there is to much to do to keep the relay and no1 can really give me a straight answer on how to wire it up so i was thinkin just supply power to the wire under the carpet and then find the ground and ground it and i should be in buissness but if u know how to wire up the fuel pump i would greatly appriciate it if u told me how, thanks

 

I can't tell you exactly how it's wired up because my car never had an electric pump, but I just got done wiring one up with no computer involved whatsoever and it works just fine. Maybe you can figure out how yours works after I explain how mine works.

I pulled 12V power out of the ignition that is hot when the car is in run, bulb test, or start. from there i have one wire going to a toggle switch. Then I have a wire that goes from the toggle switch to the oil pressure switch. Then another wire that goes from the oil pressure switch to the fuel pump relay. At the fuel pump relay that I have, there are four wires. One is power directly from the starter (about 12 gauge), and one is a 12 gauge wire going directly to the fuel pump. Another is a small 16 gauge or so wire that connects to ground and the other is the same size coming from the oil pressure switch. Wired up this way, the fuel pump only comes on when the toggle switch is set to on, the oil pressure switch is set to on, and the car is in run, bulb test, or start.

I was looking at the wiring diagram for your ecm and it looks like if you measure the resistance of the fuel pump and put a resistor in series with the tan/white wire with the same resistance as your fuel pump, the computer would never know the difference. In other words, find a resistor of that value, wire one end of it to the tan/white wire coming from the relay, and the other end to whatever ground is down there. Then, buy either some sort of universal relay similar to what I described, or painless performance sells a fuel pump relay kit (what I have), and wire it up as I described (the toggle switch is not necessary though).

 

thank you very much but i am still very confused, i know there is a way to wire it and get it to work i just needfor sum1 to tell me how. i need to know about my car not just an electric fuel pump in general. thanks

 

You just did one sollution.....only problem as Ricktpi just said, if you have a crash, heaven forbid...the pump will keep running adding fuel to a fire.....do a search on the subject,,,the answers are there....Im to tired to type tonight..

 

i did di a seach but i got confused, now with the way i didi it with the wire under the carpet into the fuse panel can i take the relay out from under the hood or no? also i heard u can run it to the oil pressure switchbut i have no idea wut that is and wouldn;t i have to crank my engine till it gained pressure for it to start? oh and if i ever do get in an accident i mine as well burn cause with all the work and money i have thrown into my car and i stll don't even have my license if my car if wrecked i will wunna die lol

 

LOL

I left the relay on the firewall alone......still going....... The pump will run all the time...the Malory will regulate the pressure..as it circulates it also helps to keep the fuel cool..

 

If you supply voltage to the pump directly, which is what you did I believe, then you have bypassed the relay. If you want to take it out be my guest. I can't tell for sure w/o looking at what you did. Just don't do anything you can't undo later.

 

well wut i did was took up my carpet under the back seat and cut the tan and white wire and added some wire and put it into the fuse panel. it worked when i did this and when i unhooked the wire it just cranked so i guess i got it. i should of unpluged the relay and tried it huh?

 

Couldn't hurt. I think you have it hot wired from your discription, so unpluging the relay shouldn't effect anything.

 

ok cool cause i was gonna do that and put a 20 amp fuse in line and a switch and hide the switch as a secruity thing

 

Mine wouldnt work with it.....the pump would prime only then shut off. guess the ecm was still in cintrol some how..wired around the relay, worked like a charm....hotwire...relay whatever it seems to work pretty good, keeps my fuel pressure level at 6psi(with a Malory three port)

 

I meant get rid of having a relay, period. I realize that the stock one probably won't work very well (I didn't look at how it was wired when I put up that first post), but a universal relay or aftermarket fuel pump relay would be a good idea so that one wouldn't have however many amps that are going to the fuel pump running through the switches controlling it.

 

Not a big deal. 30 amp 12V switches are in abundance, even at radio shack. Heck pep boys even has them.

 

True, but what about an oil pressure switch if he were to use one?

 

Can I just hook up and inline fuse and jump the fuel pump relay. i hgooked uyp the hot wire to the realy to a turn key power source. Wht if I just get an inline fuse and connect the circuit at the relay. Will this work ok? Will a 20 amp inline fuse work. Also, with the oil pressure switch, how do you hook it up. What if i start cranking the engine? The switch will not engage and the pump wont prime the lines until their is oil pressure right? Will this work ok?

 

EDIT: I need to test the way I have it wired. It will work fine on a carb because it already has fuel in it but I'm not sure about fuel injection. I'm going to pull my spark plug wires off of the distributor cap and crank it and see if the fuel pump comes on.

 

I have a carb so that is what im running it for. You say it will work fine then right?

 

It works without any problems, and I can't tell the difference between the way this one is wired and before when I had a mechanical fuel pump. In fact, with that toggle switch I put on, a few times I have switched it off when I left my car so someone couldn't easily steal it, and when I came back I forgot to switch it back on and it would run for about 3 minutes without any fuel pump at all.

 

i say if your just going to rig it then hook it to a switch you can turn it on right before u start the car i wouldnt hook it were it stays on on with the key on cuz i did that when i went from a 2.8 liter to a 305 and every time i cut my key on just to listen to the radio (with engine off) the pump just kept running

if u ask me i say just take the pump out or do like i did when i switched engine i hooked a regular pump up and sucked gas out of the return line cuz it wouldnt suck through the electric pump and didnt have to worry about a regulator or hooking up the electric hope that helps

 

Switch the key to acc. the pump wont run......

 

hey guys yesterday i sorted out all my tbi wireing for the carb swap and realizred that only one wire from the fuel pump relay was cut and its the green with a white stripe. now if my memory serves me right isn;t that the wire that need to be in the fuse panel with 12v when the key is on? so can i just hook this up and i stillo have the relay and the oilpressure switch??

 

all you need to do is plug the oil pressure switch back in and run a 3 port regulator and the fuel pump will function just fine. i did this same thing to an 89 formula last summer so i know it works just fine. no need to doubt me btw, consider the oil pressure switch a safety feature and use one!

 

The pump came on after about 5 secs of cranking for those curious about my test.

 

ok wait so i do;t need to run this green/white wire to anything? and if i do have to run it to the ignition on 12v key on then would i still need to fuse it or no cause its still goin threw the relay?? cause everywire on the relay is hooked up except the green/white one.

 

How will the pump run without the ECM on board? the computer shuts down the relay...no power after the prime. Been my experience and a lot of others.

 

Now, I'm confused. Funny thing though, I'm just finishing up a v6 to v8 swap and going from multi port to carb. I have the regulator all hooked up with the stock pump in the tank. So the reason that it will start and run for a few seconds and then die out is because of the fuel pump relay? And to fix this I have to jump the relay?? The fuel pressure drops off after a few seconds, like the pump quits working. Does that have to do with this relay?
Thanks in advance for any help.

 

Riley's, you don't need an ecm to run the fuel pump when swapping a carb onto a TBI car. this i know from experience. i will not comment on tpi or mpfi since i don't have first hand experience. however, i will bluntly state that i believe all would behave the same.

CLH, do you have your fuel pressure switch connected? if not, that explains why the fuel pump will only prime for 2 or 3 seconds giving you such short run times. find the connector for the oil pressure switch and jump the terminals.

89formula#1, if you need any help drop me a line. i'm in southern nj also.

 

hey rancid when i ripped out all the wireing i didn;t need there was only one wire from the fuel pump relay that needed to be cut and it was green with a white stripe. now am i correct is saying that if i run this to my fuse panel in a spot that is hot only when the key is on that mypump will work? or would i be better off just runnin the tan/white wire from under the back seats to the fuse panel key on? thanks man

 

Honestly, I have no idea. Where would I find the fuel pressure switch?

 

89formula#1, i prefer running an oil pressure switch as a safety feature. if the motor loses oil pressure the fuel pump will shut off. if the pump is hardwired then the motor will continue to run if oil pressure lost. i don't have a schematic handy or else i would try to answer your question.

CLH, i'm not sure where the switch is found on the V6 cars(if you are trying to use a modified factory harness).typically the v8 cars have it above the oil filter.

 

but i still have the wire from the relay hooked up to the oil pressure switch above the oilfilter in my block. are u sayin that by hotwireing the green wire i am not gonna be usein any of the relay?

 

why did you alter the wiring at all?

 

I swapped in a 60's 327...no oilpressure switch. ecm disconnected from fuel system...the pump would not run without bypassing the relay between the back seats. its what I had to do.

what controls the relay...tells it what to do???

 

Hey Rancid87 ,

why dont you update your profile a little, I'm kinda curious who we are dealing with here.......Ive never heard your method before. Ive been around here a little while...I'm no mechanic so I have a hard time arguing. But my personal experience is much. I'm a Carpenter with a fast car. What are you?

 

Riley's, the way i see it the fuel pump initializes for 2 seconds when the key is turned to the ‘on’ position. when the oil pressure switch realizes there is oil pressure the switch will close and the relay will be energized allowing the fuel pump to run. if the oil pressure switch is missing/bad the switch will stay open whether pressure is there or not and will keep the relay from energizing which in turn keeps the pump from running. This is just from my experience and i can always be wrong

 

If you take my design and add a wire going from whatever wire engages the starter and connect it after the oil pressure switch, I believe the pump will run when the starter is engaged, and turn off when there is no oil pressure. That being said, Holley makes an oil pressure switch that I think does this same thing. It has three terminals, one for a starter wire that is normally open, one for the ignition that is normally closed, and one for the fuel pump.

 

Rancid I never did find that fuel pressure switch, but I jumped the oil pressure switch/relay and the pump ran with no problem, except it ran all the time even when the key was off. I wired it to a toggle switch and all is good. Just have to fix the timing and tune the carb and I'm done.:lala: (For now anyway.) Thank you for the info.

 

good to hear , CLH!

 

If the dark green/wire is put to any hot source (which is what the ECM does anyway) the fuel pump will run through the relay.

Andy.

 

Where exactly is the fuel pump relay?

 

I'm swapping a 350 into my v6 89 RS.

 

hope this helps...https://www.thirdgen.org/techbb2/sho...uel+pump+relay