Hi there, I am in the midst of doing a Late model 5L EFI upgrade. i am to the fuel delivery part and would like a few suggestions from people that have done this. I am aware that there is a return line on the 72 comet going back to the fuel tank. Are you guys using a highpressure pump under the rear of the car or are you using a low pressure pump in the rear of the car feeding a high pressure pump in the engine bay? What should I do here?
I used a high pressure pump in the engine bay for mine. As far as the return line you need to take the fitting off on the tank and drill it out bigger. It is about 1/32 right now. I think i drill mine out 5/16.
did you feed the high pressure pump with a low pressure and have a fuel accumulator, or did you just have only the high pressure? I hear they are no good for sucking fuel from a tank.
im going to mount my high pressure pump on the rear frame rail near the gas tank. like mike said, you can use the vapor return line, just drill out the vent on top of the tank for adequate flow back to the tank i dont think Mike ran a 'pusher' pump, just the high pressure (puller) in the engine bay
On my EFI set up I ran two new hard lines 3/8 for delivery and 5/16 for return . The pump I used is from a mid 80 f150 frame mounted boost pump . I mounted the pump at the left front corner of the tank as low as posibilty then gravity feed the pump ( most electric fuel pumps are made to push fuel NOT pull fuel ) . For fuel return I solder in a double inverted flare fitting in the upper right front corner of the tank .
You DO NOT want to use your Emissions Charcoal canister line as a return.... your gas tank needs to Vent, I ran a seperate 3/8 line back to the tank on the frame rail... and had a fitting welded onto the Tank.
Due a search on efi feul pump you will see a post by 89gtsleeper title '' Fuel pump for a fuel injected 306 maverick '' you will see many post on my on cnoversion and some pic . DON'T USE THE VENT LINE AS A FUEL RETURN . Jay
Just curious. Do you install a shutoff switch to kill the pump in case of a collision? Seems like a good idea for any electric fuel pump but expecially for the high pressure efi pumps.
at this point I am seriously trying to do it without having to do any welding back there. The tank is full of fuel and I would like it to remain that way.
I'm running an inertia cut off switch with my 2.3 EFI swap. Got it out of the trunk of a '95 Crown Vic Police Interceptor at the local junkyard. I'm wiring it up to two relays so that it will kill both the ignition and fuel pump in case of an accident, though power to the rest of the car will remain on. Wouldn't be too hard to make it kill power to the entire car though, now that I think about it. I may do that instead... It will be mounted on the side of the brace that runs from the tail panel to the floor of the trunk that the trunk latch is also bolted to. I'm using 3/8 steel brake line for both my feed and return. I drilled a hole in the filler tube and bent a piece of 3/8 steel line into an upside down U shape, and had my dad TIG weld it in. High pressure fuel injection hose will connect that to the return line which will stop at the back side of the gas tank.
I like the sound of that! I saw a guy burn up when his fly wheel exploded and cut the fuel line on the down stream side of the pump. Makes you think.
hey jamie. you might want to see if slaming the trunk will triger the switch. ive put several fuel injection systems in cars that didnt come with them origanly. i will punch a hole in the tank with a center punch and then use 1/8 npt tap to thread the metal that is pushed in then thread in a fitting to run the return to. ive sometimes put the fiting in the fuel level sender and sometimes into the tank wall it self.
I don't think kit would even be close to triggering it, but I don't slam the doors/trunk on my car either. The only way I can trigger the switch is to hold it in one hand and smack it real hard with the other. Takes a pretty good hit to make it pop. I may move it, that's just where I've been eye balling on putting it. I just figure that would be the place where it would trigger the fastest if the car were rear ended.
i used to have a bunch of friends with fox mustangs and we would mess with each other when anybody would have there hatch or trunk open by giving the interior pannel a thump with a fist. worked every time. also those swithes had a problem of buring out causing no fuel pump operation.
