Rich123

I have read several post on here about installing an electric fuel pump, but I could not find where I need to get power from. I read that there is a fuse block and it may have spare slots. The only fuse block I've found is under the dash on the drivers side and it doesn't have a spare slot. I know I need to connect to a source that has 12 volts when the ignition key is on and that I'll need a 5 amp fuse. Is the block under the dash only active when the key is on? Where would I hook up to it and maybe use an inline fuse?
Thanks
Rich

7T1vette

Why do you want an electric fuel pump? Buy new pump ($$); remove old one and install block-off plate ($); plumb new one into lines ($); connect electric power and fuse to pump ($); purchase pressure regulator ($$); plumb regulator into the system ($); 'adjust' fuel lines as needed ($); not to mention the time and trouble required to do all of this.

To what end? What will the electric pump do that the mechanical pump will not? (except add multiple failure possibilities to your fuel supply system)

It's your car, so you are free to do whatever. But, since you wanted "input", I thought I'd give you the opportunity to 're-think' your plan....

Doug1

I have the same thoughts as 7T1vette, lol.

To answer the question, get a test light. There are some "prongs/blades" on the middle of the fuse box. I believe some of them are hot all the time, but there may be one that is only when ignition is on. Electric fuel pumps push the gas, so it will need to get installed back near the gas tank.

Rich123

After sending the carb to Oklahome to be rebuilt and tested twice, replacing the fuel pump once, adding an inline check valve between the carb and the pump, I am up to my eyes sick and tired of not being sure if the engine will start without pulling the air cleaner and priming the carb with raw gasoline.
The pump I put in 3 years ago quit so since I have to pull it anyhow, I'm taking this opportunity to replace it with a pre-start active system which will insure the carb is primed and ready to go when I turn on the key. It's pretty simple you should try it

Rich123

So you don't believe the fuse block is only active when the key is on? Maybe I can find a wiring diagram that shows where the 12v goes to from the ignition switch.

'75

In the fuse block, there will be a terminal marked batt, it will have power at all times. Terminal marked Acc, will have power with key on and key in acc, but no power while cranking. Ign terminal will have power with key on and also while cranking, this is the one you need to use for a fuel pump.

Rich123

Great, thanks, I'll look for these.
I've got the same side pipes on my vette

ignatz

You really should insert a relay, fused of course, to power the pump.

The other consideration is what happens if you're in an accident and the pump continues to operate. Lots of discussion available on that subject.

Doug1

Sorry you are having this problem. I have a holley double pumper, I press the gas pedal a few times, then crank engine, it fires up IMMEDIATELY. I don't have an inline check valve between carb and pump.

Doug1

Rich123

yes I did read a lot about the safety issue of the pump running and spewing gas after a wreck. I liked the idea of the oil pressure switch shut off, but then there is no oil pressure when I sit down to start it, so it would act pretty much like the mechanical pump. It would take some other creative idea to get around that, like a 5 second oil pressure switch over ride to send power to the pump when the key is first turned on. Right now I'm just trying to find the best source of the 12 volts needed. The other can come later.

Rich123

Yes, I think replacing the Q'Jet with a Holly would resolve the problem, but then a nice Holly double pumper is mucho $$$$$. If that car sits for a couple of weeks, I can open the hood, pull the air filter and manually pull the throttle open. On the first pull I'll get maybe 1/2 the normal squirt, the second pull is almost nothing and the third pull is nothing. If I crank the engine in cycles for 5 seconds, then 5 more seconds, then 5 more seconds, all the while pumping it a couple of times each, after the 3rd or 4th cycle it will usually start. I just hate what that does to my starter though. I usually hit the pedal three times and hit the starter. If it doesn't fire immediately, I pull the hood and the air cleaner and pour in about two tablespoons of gas. It will fire instantly after that.

ignatz

I don't know your background. I built an Arduino-based controller that sensed when the motor was being cranked and turned the pump on. However the float bowls pretty much always supply enough fuel to get started.

In my case with an LS transplant, this sort of add-on was necessary but I have to tell you it was a lot of work. The best solution is still to get a reliable mechanical pump and carburetor.

ignatz

If $$$ is keeping you from fixing your underlying problem, have you tried squirting some starting ether on the air filter?

Rich123

"Arduino", interesting tools. I did not know they existed. I'll have to look into them for later projects.
Putting together a capacitor/resistor/switch or relay to give me a 5 second shunt around the opened or closed oil pressure switch shouldn't be too difficult, but I don't multitask, so it's a project for after the current project.
My background...a few years, with IBM, waaaay back when, designing the equipment that made the wafers, that were cut up into chips, that powered the main frame computers. Really fun, challenging projects while I was there. Some of the equipment was so cutting edge, it was like a syfy movie.

PS: "LS transplant"; I'm jealous. That's where I would rather be but I don't think it will ever happen.

Rusted40

Quadrajets have a lazy accelerator pump and can be extremely cold natured if the choke isnt set up perfect.
This is hard to set up on a bench and is best done on the car.

On the vehicles I've owned with a Q-jet, cold starting involved what would seem like an excessive amount of throttle pumping.
My dad had several 8.2 Caddys over the years and the big engines required 8 or 10 pumps on the throttle before they would start.

Carters and Edelbrocks arent much better, although they do have a rod/lever adjustment that helps.

I actually set mine up a litle cold natured, not dumping a bunch of raw fuel in a cold engine fouling the plugs and oil.

F22

I'll say this, it's not easy finding a spot for an electric fuel pump on these cars. I plan to put mine on the underside of the rear frame crossmember, behind the bumper on the passenger side., about halfway between the centerline of the car and the end of the crossmember. This seemed to be the best way to do it, without getting too close to the exhaust or too far away from the fuel outlet of the tank (on the passenger side). You'll just end up running more rubber hose or braided line (your choice) than necessary, because the beginning of the vehicle's steel fuel line is right there on top of the right rear frame, almost where it ends. I looked at it carefully for twenty minutes, with a Holley Blue electric fuel pump in my hand.

I looked also at the empty four inches up inside, under the rear window for mounting but you'd have to reinforce the fiberglass. There is already motor vibration from the pump and would probably transmit the vibration really well! The frame on top of the diff? I didn't like that either, no way to really attach wires and hoses or lines, without welding tabs, because I don't trust big zip ties, that much. So the final rear crossmember it is, for the previous reasons. Some people probably have mounted it, in the engine compartment, but I thought, close to the tank is better.

Next is wiring and you're going to need a relay, because I wouldn't want to run a wire that long, from the back of the firewall, all the way to the rear bumper. I also wanted to run the pump, straight off the battery, so it gets direct power, through a switched relay, with the switch mounted somewhere in the dash (there's not really a lot of other places in these cars). That way, the wiring runs stay at a minimal length. I have an Painless wiring auxillary fuse box on the front of the firewall (as I have other accessories). Starting at the aux fuse box, I ran it along the firewall with the factory wiring, through the firewall hole by the driver's fender and then, to where the stereo used to be. That's where the toggle switch will be, mounted on a piece of sheet metal.

The next wire run from the switch, goes from the switch under the shifter console, seat console, up and into the pass. side compartment. In there, is where I have a standard Bosch Relay. The switch when powered on, puts the main battery power, right to the pump in a separate loop. You can ground the pump to the frame with the built in ground on the pump, to complete the circuit. To run the power wire to the pump, from the passenger rear compartment (where the relay is bolted now), I drilled a small hole, from the inside of the compartment, on the outward side, near the top and then took the passenger rear tire off and pulled the remaining six feet or so through the hole. I then zip tied it to the steel fuel line, on the back side of the line, facing away from any debris and used zip ties every 18". I then ran it to the back of the frame and there's plenty of holes you can use. I haven't mounted the pump yet (but did test it with test lead clips and it worked fine (one to the newly installed power wire and one attached to any ground).

F22

chevymans 77

Use a relay, us the Acc to power the control side of the relay (power on with key) and use a dedicated wire from the battery or from the alternator to power the pump.

A true oil pressure safety switch will pull power from the starter solenoid so the pump will run while cranking then will stay closed as soon as the oil pressure gets above 5 psi. You could add a timer to the Acc power side to allow the pump to run for a given amount of time prior to cranking if you are concerned about priming the carb or add a bypass push button so you can prime it prior to starting.

Neal

Richard454

Here you go- everything already pre-wired and ready to go in a package.

Uses the tach signal to monitor/control fuel pump AND has a built it relay PLUS primes the pump for 3 seconds with initial key on

http://www.revolutionelectronics.com...ty-switch.html