i cant seem to get my fuel pump to work. i have an in-tank fuel pump with a return line. im in the process of a a TPI ->carb conversion and i think when i ripped the ecm out i may have cut the fuel pump wires. i tryed to apply positive battery voltage to the bottom left terminal on the ASDL and nothing happens. is my fuel pump toast? i cut every single wire that goes down into the passanger side pannel to the ecm. im also going to post this in the electrical board too.

 

go take out your back seats and pull up the carpet. Right in the middle there should be your fuel pump wires. If you get under the car and look you will see them coming from your gas tank and into the car from behind the back seat. I forget the color of each wire but there is power, ground, and one for the guage. Try hot wiring it that way. Once you remove the computer the ALDL connector and everything is a useless peice of scrap metal.

 

so technicaly all i would have to do is touch a positive battery power source to either the grey or purple wire to get it working? do you know where the wires go after they enter the interior of the car? do they go straight to the ecm mabey?

 

I'm actually doing the same swap right now. Does anyone know where I can find the relay wire fo the pump farther forward? I would like to tie in to a keyed ignition source farther forward. Does anyone know the color? Thanks!

 

umm.... i wouldn't recommend putting 40psi into a carb that only takes 6psi. i know a guy that did and his whole engine bay caught fire. leave the stock pump as is and either get a mechanical pump or get an inline LOW PRESSURE electric pump and stick it by the gas tank.

 

The reason you have to use a low pressure pump is the fuel flow into the carb is controlled by a spring loaded needle valve. It is only designed to hold around 7psi max, 40 psi will ovecome the spring and you'll totally fill the fuel bowls with fuel and it will shoot out the vents. A TPI pump moves ALOT of fuel, and if you have this happen on a hot engine youre very likely to have a severe engine fire.

Your other option is to hook the stock tpi pump back up and use an aftermarket 3-port fuel pressure regulator that will bring the fuel pressure down to 5psi or so.

 

I'm assuming these guys are using a fuel pressure regulator.....

 

you will have to remove your fuel pump inside your tank and your best bet is a 5-9 Lb. inline fuel pump,(13.99 at auto zone Vs. 80 for a bypass) if you use your TPI pump your gas will flow out the top of your carb........ i found out first hand and bent 2 valves in the process it filled my cylinders full of gas and when it went to push that cyl up it bent my valves

 

Make sure you know which wires you are hot wiring. One of those three succers is for your fuel gage. It will work without the computer and uses less than the 12 volts to operate. If you want to figure out which is which turn your key on and probe them at that connector previously mentioned. Your power for the fuel pump will probably be 0 volts and the one for the fuel gage will probably be about 7 or so. The black one should be ground.

And just for FYI if you are running a Q-jet even 7 psi may be to much. I was using the Holley Red pump (the smallest one) and it was sending fuel through the vents and top gasket on the carb and out the gasket on the fuel pump itself. I was getting about 8 to 10 mpg. Not good. I think when holley says no regulator required they are assuming you will be running WOT every where you go.

 

tan is power (12 v)
pink is for your fuel gauge
black is ground

 

trans-am-racing nailed it. I took the tan wire that went to the relay on the firewall, and wired it from there.

 

88 roc, Yes, I thought that went without saying, yes I am running a regulator just like yours. I even mounted it in the same place. That car of yours is sweet! I would love to see a better pic of the engine bay!

 

yeah, i have a fuel pressure regulator too, all the lines are hooked up as they should be, the only problem is i cant get the damn thing to turn on. what tan wire are you talking about? i choped the wires going to my ecm, so will this relay still work? do i actualy NEED this relay? or can i just run a wire going directly to the ignition power source? what is the simplest way i can make this stupid pile of wires get fuel so that i can drive again??

 

heres a pic of my engine bay

 

your tan wire to your fuel pump is along the drivers side kickplate runner rocker what ever it is, it runs with your real lights but only the pink black and tan are in there own wrap of tape

 

I dont wanna hog up loading time on this thread so check out my post on nethirdgen.org. Lots of pics of my car and motor:

http://www.nethirdgen.org/cgi-bin/ul...c&f=1&t=023638

 

From the picture, I can't tell if you still have the factory fuel pump relay in or not. If you do, there will be a tan wire coming off of it and it goes into the firewall on the drivers side. Once again, trans_am_racing's idea of looking under the door sill plate might be easier. I ran 2 new relays, one for the fuel and one for the fans. My wiring looked a lot like your when I started. By the way, don't give up. I cut all wires to the ECM also, and my car runs great. It can be done, just find the tan wire. If I remember correctly, it was the only tan wire that went into the fire wall on the drivers side.

 

ok... do i actualy NEED the fuel pump relay? if i do, what for? how about those fan relays anyway? where are they? ill attach a pic with a close up of some unknown relays..... atleast unknown to me. one is a maf relay i think....

 

I believe the one closest to the fender is what you want.

 

reply: .... no you actaually dont need any relys or any of the bs if you want to run your car, elimante all computer, goto to the auto store, drop your tank, remove your exisitng pump replace w/an
5-9 Lbs fuel pump, hook it up, w/non cc carb and away you go....

 

dude you can't run a fuel pump straight off your fuse box, you need a relay

 

then how is mine working just fine then? i have no relays or computer sh8t either

 

trust me bro, gm wouldn't have used them if you didnt need them. a fuel pump draws a lot of current and you risk melting your wires and starting a fire.

 

ok, i have a return style fuel pressure regulator hooked up, all the fuel lines hooked up and i went through alot of trouble to do it too. im not gona just forget about the 50 - 80 dollars i spent doing it. i need to hook up my old pump. eventualy i will probly change the fuel pump but untill then, im going to use this one. droping the tank is not as easy as you make it sound, its alot of work. i dont have a huge hydrolic lift in my garage either. what i need to know is where this relay is and what i need it for. are you really sure its the one near the fender? those wires look completely different from the ones near the tank. how do i hook it up? im guessing the original wires went straight to the ecm and then to the relay, right? one thing that worrys me is, whats stopping the fuel pump from flooding the carb every time i turn on the accesory power?(the click right before the ignition one) is that what the relay does mabey? im guessing i have to wire up my fuel pump to be on during accesory power right? why does it seem like everyone whose done the tpi->carb conversion knows next to nothing about it? do most people just take it in to a shop and say that they did the conversion?

 

As long as your fuel pressure is low enough you should be able to run the fuel pump without the car on and not flood anything. There is a little "needle" that only allows a certain level of fuel into the bowls. It'll just close and not allow anymore fuel in. All the fuel will back-up and start going into the return line.

You really should use the fuel pump relay. Currently my pump is hot wired directly to the ignition and it draws a lot of current. As soon as I get everything put back together I'm running to the junkyard and finding a relay to hook it up to just to be safe but so far I've been running without one for 5 months.

 

well, so far no one has been able to tell me what exactly that relay does. if you have been not useing one for 5 months, what difference would useing the relay make?

 

my point exacty, i dont have one and dont have any problem with my wires getting hot, dont have one dont need one, i have a spare if anyone wants it

 

i looked at some wireing diagrams, and there is alot of wires going from that relay to useless stuff, like the maf sensor (for some wierd reason...) mabey the ecm just used that relay to calculate some fuel delivery stuff. i seriously cant think of why i would need it otherwise.

 

The relay is used in the stock setup so that the ecm can control the fuel pump. Without the ecm you don't need the realy. You can just wire the fuel pump into the fusebox to come on when the car is on. You need to be careful that you use large enough wire, and that you wire to a termina that is switched, but stays on when cranking.

A better way to do it, and how I have it on my car, is to put a relay up near the battery and run your own new circuit with nice thick wire back to the fuel pump, and then use a switched ign wire to turn ont he relay. This helps you get the most voltage possible to the fuel pump.

 

i never thought about that.... how would i wire it up to the fuse box so that it come on while cranking and while in the acc position? im not quite sure about this whole fuse box thing, there are so many freakin wires going into it its hard to pick out certain ones. where does the fuel pump wire go after it goes to the fuse box? you said wire up a new relay... how would i do that so it comes on while cranking and while at acc? why would i need a relay to get more voltage? wouldnt i need a capacitor or something for that?

 

i have my pump in the fat orange wire, the only one in the fuse block thats that fat, theres 2 empty wire clamp things you can use a pair of needle nose pliers to pinch your wire into that, it uses the less amount of power in the fuse block when cranking, i tested it,