Fuel Pump Question

City
Raleigh
State
NC
#1
So, I believe the fuel pump on my "new" '84 may have gone out. It started to stutter on me while cruising at about 35 mph then cut out all together while accelerating out of a turn. I was able to start it back up and get it to back to my house, but it wouldn't start after that. New battery, cranks fine, oil pressure is fine so my guess is that no fuel is making to the motor. Does this sound like an accurate diagnosis? If I am replacing my fuel pump, any advice other things I should do while I'm at it?

The PO swapped a 4.0 i6 out of a 94 YJ in my '84. Would this swap have moved the fuel pump to the tank? Thanks for any advice!
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#2
There have been a few successful in-tank pump installs, but it's more common to find an external pump mounted to the crossmember right in front of the fuel tank.

There's a schraeder valve on the fuel rail for checking the fuel pressure.

I hope it's an easy fix!
 

HighSierra CJ

Scrambler Enthusiast
LIFETIME
CJ-8.com Member
City
Ducor
State
Ca
#3
I would check your fuel filter first. The pump may be in the tank, or it may be mounted near the tank on the outside. But also might be a loose connection on the wiring of your fuel pump.
 
City
Raleigh
State
NC
#4
Since I've never had a vehicle with an engine swap, when I go to buy a new fuel filter, would I buy it for the 84 Jeep or the 94 engine?
 

HighSierra CJ

Scrambler Enthusiast
LIFETIME
CJ-8.com Member
City
Ducor
State
Ca
#5
I would try to identify what filter you have first. It’s probably mounted on the rail near the fuel pump. Get the same one because it will fit in the bracket that holds it in place. The filter might not be year/engine specific
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#7
If you have an electric fuel pump (most likely since you have a 4.0) the fuel filter will more than likely be right before or after the pump. Pump could be anywhere in the feed line depending on how the swap was done. I'd start under the jeep at the fuel tank and start following the lines forward until you see the pump. If you never find it, then it is in the tank.
 

Chamba

Active member
City
Vero Beach
State
FL
#9
Sorry, i just found this post. I put the Holley 12-307 in tank pump in my factory 15 gallon tank. It produces 58 psi, which works perfectly with my FiTech.

Very easy install. Simply pull the tank, remove the old sender unit and put the Holley right back in the hole you pulled the sender out of. Then run fuel injection fuel house and a filter and Bob's your uncle.

If you don't clean and paint the tank like i did, i suspect you could accomplish the whole project in about 3 or 4 hours.
 

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Chamba

Active member
City
Vero Beach
State
FL
#11
If Bob's you're uncle, then he's your mother's brother. "Mother's brother" is Cockney rhyming slang to rhyme with "one way or another (as in 'finish it one way or another')". But that would be too easy, so take it to another level. Thus, Bob's your uncle (your mother's brother). .. it's an Aussie thing.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#12
Who is Bob ? Thanks for the info ! Was your gage accurate before and now ?
I am! :P (At least to 3 people.)

I don't think it is exclusive to oz. I've said that for years. I always took it to mean, "and there you have it."

Or, it could mean, "I'm baby stepping, I'm doing the work!" :rotfl:
 

Chamba

Active member
City
Vero Beach
State
FL
#13
Who is Bob ? Thanks for the info ! Was your gage accurate before and now ?
My guage was terrible before. It was accurate for the first 1/4 tank, then went to E and stayed there. Now it's pretty good. First pic is 5 gallons, second is 10 gallons and full is full, so no need fur a pic of that. Thus the first half is only 5, not 7.5. Still, it's consistent and that's what counts. Now i can actually use it, rather than mileage.
 

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TravelnMan

Legacy Registered User
City
Granby
State
CT
#15
Filing this away - I did an external pump for 58/60 psi. It lasted around 8 years, maybe more with very few miles. Next time it fails this is the way I'm going. Looks like the easiest setup ever to keep it in the tank.
 

Belizeit

CJ-8 Member
CJ-8.com Member
City
River Ridge
State
La
#16
Just got credit back from Holley on a universal in tank pump I bought a year ago but had not installed. Going to order the 12-307 ASAP !
 
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