Electric / mechanical fuel pump combo ?

[jeepboy45]

Hey guys, its been a few months since I've been on here, and I have a question...

I think the Edelbrock carb on my 360 has issues. After sitting for just one full day, I have to crank the engine nearly 20 seconds to get fuel to the carb. It appears to be "draining down" over night, and have to basically prime the system after sitting...


I considered installing an electric pump that I'd manually switch on before turning the key, just to prime the system. Obviously what I SHOULD do is just fix the carb or get a new one.

Just curious if anyone knew what might be happening at the carb..

thanks,
brian

 

[Scooter402]

Hey guys, its been a few months since I've been on here, and I have a question...

I think the Edelbrock carb on my 360 has issues. After sitting for just one full day, I have to crank the engine nearly 20 seconds to get fuel to the carb. It appears to be "draining down" over night, and have to basically prime the system after sitting...


I considered installing an electric pump that I'd manually switch on before turning the key, just to prime the system. Obviously what I SHOULD do is just fix the carb or get a new one.

Just curious if anyone knew what might be happening at the carb..

thanks,
brian

Before you go through the trouble/expense of plumbing in a primer pump...here's a couple things you could check out.

First, the easy one. How do you start your Jeep? I know, dumb question... Do you tap the accelerator pedal a few times before hitting the key, or just simply turn the key? I'd try pumping the gas 2 or 3 times before hitting the key.

Along with this first step, I'd remove your air cleaner (after it has been sitting for a day) and pump the throttle. Do you see a shot of gas going down the venturi?

If not, it gets into the little bit "more difficult" solution. You may need to purchase a rebuild kit, which are approximately $35 last time I bought one (was probably nearly a decade ago...). You'll need it for at least the top cover gasket. Once you go that far, you may as well do a full rebuild. Not as intimidating as it sounds.

My point here is to see if when you pull the top cover plate, if you still have fuel in your fuel bowls. They should still be nearly full. If not, it is somehow draining the fuel bowls down into the engine after it shuts off. Does it run rich at all? That would be an oddity for Edelbrock carbs, as they are factory tuned to run a bit on the lean side anyway.

It's not an impossibility to plumb in a primer pump, but it would take a bit for it to force the fuel past your mechanical pump. The right way to do it is to put in a fuel line and check valve setup from your tank to bypass your mechanical pump. That way you don't end up pushing out the seals in your mechanical pump.

Let us know if you need any more help.

 

[jasonmark1993]

Like stated in the above, I would check for the shot of fuel before starting.

Put a clear fuel filter between the pump and carb to see if the pump is allowing the drain back or unhook your fuel line and crank after it sits overnight and look for immediate fuel

Probably a worn fuel pump.

 

[jeepboy45]

Thank you for the imput guys,

For some reason this site stopped sending me email notifications when there replies to the thread. I had no idea anyone had responded, or I would have read them and said "thanks" before now...


Last month I decided to go to a TB injection setup for several reasons. Havent finalized the installation yet, but I'll turn the key on it soon.

but thankyou for the imput..

Brian

 

[gert]

as much as I love Edelbrock carbs you will love the everyday drivability of the TBI set up

 

[jeepboy45]

as much as I love Edelbrock carbs you will love the everyday drivability of the TBI set up

How did you mount your fuel pump.

I'm looking into getting a later model tank with electric pump in the tank.

Unfortunately I bought a 15 gal tank out of a 1995 wrangler to swap in.
I hadnt seen the configuration of it, until last night when I saw pics of its very odd shape. I read where someone used a 1990 wrangler and it fit perfectly. Should have waited till I did research.

Also read of people installing an electric pump at the end of the stock pickup tube and running power down into the tank.

Again, should have done more reading before I spent $$

But looking forward to resolving this and turning the key on it.

 

[Torxhead]

Jeepboy45, for an external mounted mounted electric fuel pump, most recommend installing it at or below the bottom level of the fuel tank, this is the way mine is set up. In the case of the Mopar MPFI system they have you install it as close to the tank as possible, so there seems to be two trains of thought just to get you more confused.

 

[harleydragon]

Jeepboy45, for an external mounted mounted electric fuel pump, most recommend installing it at or below the bottom level of the fuel tank, this is the way mine is set up. In the case of the Mopar MPFI system they have you install it as close to the tank as possible, so there seems to be two trains of thought just to get you more confused.

it should be mounted below the fuel level AND as close to the tank as possible..reason being that they are designed to pump ( push) not pull

 

[Torxhead]

it should be mounted below the fuel level AND as close to the tank as possible..reason being that they are designed to pump ( push) not pull

In the instructions for the Mopar mpfi conversion it is stated to mount the fuel pump on the crossmember in front of the gas tank. You would think these guys know what they are talking about. As I recall the fuel pressure for that system is around 45 psi, whereas the t.b.i. is around 12. This is what I can't figure out.

 

[harleydragon]

I don't know..I have used a lot of different electric pumps over the years and all I ever had said to mount it near the fuel source and at a lower level..all mine have been for carbs,usually 4-9 pounds..