[Hybrid Jeep]

Hi All-

I am replacing my mechanical fuel pump in my 1976 Jeep CJ5 with the 258 engine with an electric one. I purchased a Carter Electric Universal Fuel Pump from checker. Here is a pic:



Is there anything I should know about hooking it up? Does it require a regulator? I have the Carter YF 1 BBL carb. Where to hook the power to - I've heard oil pressure switch? Where can I find a blank plate to seal off the mechanical pumps opening?

Thanks!

[CJ Chet]

Summit sells block plates.

[4.7stroker]

Honestly if you can I would stick with the mechanical pump.
There is nothing wrong with them and it will save you some time/problems.

That said, I used one on my stroker because the 4.0 block doesn't have a provision for a mechanical pump.

I mounted it on the frame rail by the bulk head close to the fuel supply line.
I used a pipe cutter to cut the fuel line and connected it via rubber gas hose to the fuel pump and from the pump to the fuel filter using the same hose but protected it from abrasion with split wire loom.
I did use an oil pressure cut off switch, when you buy one it comes with wiring instructions.

Dwayne

[JeepHammer]

YOU MUST USE A SAFETY CUT OFF FOR AN ELECTRIC FUEL PUMP!

Unless you have a real thing for burning to death after an accident...

Your fuel pump MUST have a 'Dead Engine' cut off switch!
Simply no two ways about it!

When the engine dies, from cutting the ignition off, or from an ACCIDENT, the fuel pump must be cut off!

The last thing you want is an accident where the key is left on, with the fuel pump pumping fuel all over you while you are knocked out or trapped...

Use a Relay to power the pump.
Use an Oil pressure switch to turn off the pump if the oil pressure drops.

You can 'Prime' the pump by wiring a bypass circuit in the starter solenoid, so when you are cranking the engine, the fuel pump is running without oil pressure, but in the normal 'Run' position, if the oil pressure drops, Like in an accident, the fuel pump shuts off and doesn't continue to flood a vehicle that is wrecked.

The beauty of that system is it's self resetting.
Get the vehicle back on it's wheels, fill up the oil, and it will start again without any extra 'Fiddling' around with reset buttons, ect.
--------------------

Generic electric pumps often require a pressure regulator to keep the fuel pressure from blowing the fuel inlet valve open in the carb.
Don't even bother messing with any of the 'Generic Clones', go right to a Holley fuel pressure regulator and save yourself some time and aggravation.

[4.7stroker]

I don't know if you have a return type fuel system or not, If you do there is no need for a fuel pressure regulator.

Dwayne

[Hybrid Jeep]

Thank you for your replies.

Is this how it is all hooked up?

[JeepHammer]

Originally Posted by 4.7stroker

I don't know if you have a return type fuel system or not, If you do there is no need for a fuel pressure regulator.

Dwayne

That would depend ENTIRELY on what carb he's using,
and somewhat to the application of the vehicle...

Webber's maximum pressure (3.5 psi) is above what most Holley's require for a minimum (4 psi).

The stock Jeep 'Return System' is too much for a Webber, too little for a Holley and close for a Carter BBD or MC 2100 or 2150.
Since it was built for Motorcraft 2100/2150 and Carter BBD, that would make sense...

If you do serious low speed off road, choking back the fuel pressure is a good thing...
Helps hold off 'Tilt' induced float failure,
SO,
Until I know what kind of pressure/volume that pump is going to put out, and what carb the guy is running, I'm not ruling anything out!

PS, Does the OP need a wiring diagram for that pump with the correct safety switches built in?

Looks like you sneaked in with one while I was sleeping at the wheel!
Yes, but I'd control the ground to the relay with the oil pressure switch, more reliable,
Easier on the relay too.
Use a diode in the hot wire from the starter solenid to the pump
(so relay can't back feed the starter circuit when the relay is closed)
And you can make it more reliable since it's a direct 'hot wire' instead of through he relay.

[Hybrid Jeep]

How is this setup?

The pump PSI is unknown.. I have the Carter YF 1 BBL carb.. my 1976 Jeep Service Manual says that I should have 4-5psi at the carb. When I get it all hooked up I will test with my fuel pressure gauge.

How does the schematic look now? What kind of 12V relay should I use... what kind of diode? All Radio Shack components?

[JeepHammer]

How about this,



Like this, there is a minimum of wiring, and you can do easy connections at the starter solenoid...

Any old 20 or 30 amp Driving light relay from the discount parts place with work.

[HighCountry]

I prefer the reliability of the mechanical pump and the fact that I can get one for $18 (or less) at a regular parts store. If availability is a worry, they are so cheap you can carry a spare!

[Cherokeester]

Are there different return line fuel filters that would effectivley change the psi at the carb? I have an electronic fuel pump and I have a fuel pressure gauge installed, it generally runs about 5 psi. I have the Holley truck avenger, it all runs good except on the high end on the highway up grades. I am wondering if I am starving for fuel pressure. Thanks for schematics btw, very helpful. Oh, the filter I use is just a basic return line purchased at Checker.

[CJ Chet]

[quote=JeepHammer]The stock Jeep 'Return System' is too much for a Webber, too little for a Holley and close for a Carter BBD or MC 2100 or 2150.

Also depends on WHICH Weber is used. I have a Weber 38/38 on mine. It has it's own integral fuel return outlet, which I put into the OEM fuel return line. Works like a champ!
I like my elctric pump. Provides a more consistent pressure to the Weber, and makes start-ups much easier.

[OldSailor]

Hybrid - you're got the diode in backwards, I believe -- current flows against the arrow.

[Hybrid Jeep]

Thanks again for all your replies, and thanks JeepHammer for the detailed schematic. As far as staying with the mechanical pump - I 've already decided on the conversion. I've purchased the parts... and I'm going to do it. I tried to replace the mechanical pump, however the actuator arm was too long, so I went with electrical.

I do have a few more questions before I begin the installation today.

1. What size inline fuse to use? 10 Amp?

2. The stock oil pressure sending unit has a gauge in it and it connects to the oil pressure gauge in the cab. Will I still be able to use my oil pressure gauge if I replace the stock sending unit with the oil pressure switch noted above?

3. For the mechanical block off plate, should I use a gasket? RTV?

4. Old Sailor - JeepHammer's new schematic doesn't show a diode.. should there be one?

Thanks guys!

[illinicj]

You will have to use a T to use both the gauge sender and switch.