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Fuel Pump

B

BrokenSockets

NAXJA Forum User
Location
Ayr, Ontario
96 XJ 4x4 241 4.0 420,000 K's

Fuel pump problem. 50% of the time pump will not start, no prime noise when turning key. Tapping the front of the pump assembly while cranking, it will start running. No problems with pressure when running, never cuts out.

I guess I need a new fuel pump?

Many listed on Rock Auto from $20 all the way to $175

Any to recommend / avoid?

New strainer and tank seal also I would guess.

Or, anyone think it may not be the pump itself? I seem to have voltage, just randomly refuses to run without a couple of whacks.
 
Do an ohm check when it does not want to run. If it's open circuit then it's something in the pump that's bad. I'd get the ohm reading for the pump and compare it. I'll try and find it.

EDIT:Found one for a 93 YJ @ 15 ohms

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Last edited:
I'm not sure the 96 is the same as the older XJ, in my experience the cheap pumps with senders are junk, well they will work but sender readings are erroneous.
I try to go back with as near oem as I can. I believe that was Bosch. Might be wrong on that


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I believe you are correct on the bosh pump. Iv never had to drop the tank on a jeep but from what I remember of a friend Doing his that ring is a bit of a PITA because it sticks on. I did one in a ford and I broke bolth quick connects and just used rubber hose. Driveway job. The worst that happens in your case is you get the new pump installed and it was not the issue. Just my .02


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Iv never had a fuel pump out of any jeep. So I wouldn't know but anyone who does feel free to add in. Also they (sending unit and pump) are usually sold separate so I'd use google to find out.


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Yes its separate . The pump comes off the sending unit. As I recall the the aftermarket pumps don't really fit correctly. Different dimensions, I think I had to fabricate a way to hold it to the sending unit. But they do work. It's easier to get the whole assembly but those never work
Right.

I'm still thinking there was something tricky about the 96, Something unique .




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I read that one. Seems to be different from my issue. He was having pressure problems. I have strictly motor start issued with the pump motor and no pressure problems. Good general info though.
 
I looked at the ones rock auto has I'd go with a mid level kit, one with all the hoses, filters and wires. Just so you should have what you need to finish it.

Do you know the pump is kaput?




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Like that other thread said, 96 fuel senders are a single-year, single-model component. If a part seller online says their pump fits 91-96, it does not fit your 96, it fits 91-95. As far as I know, only crown automotive is reproducing 96 XJ fuel pump assemblies right now. You need to either replace the pump itself or get a good junkyard unit from down south where the bulkhead flange doesn't rot out like they do up here.
 
I replaced the bad pump on my 96 with a Walbro 255lph including filter. It was whiny, so I don't recommend it unless you need the lph. Get the Bosch with sock filter and swap in a new main filter while you are at it. I was able to re-use the ring. Make sure the physical ground on the plate is good and not rusty and clean the body harness connectors too. Don't lose the assembly rubber nipple/isolator in the tank(fits in a hole in the baffle).


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"Vehicle won't start until you whack the fuel tank a time or two" is pretty much a classic indication of a dying fuel pump. The nice thing about that situation is that it gives you a chance to drive the vehicle enough to get the fuel level down so that you don't have to deal with a full tank. I made The Bride put up with that situation for about a week before I replaced the fuel pump in her Impala.

Get a Bosch replacement pump and take care of business.
 
So I replaced the fuel pump, not too hard. hardest part was getting the o-ring to sit still and not poke out the gap while I hammered the clamping ring back in place.

Worked great for two weeks - no starting issues or problems.

Today it sputtered to a stop and died in a parking lot after a long drive and will not start. Fuel pump is not running, no prime noise turning the key.

Maybe I got a bad pump? Something else?

I will be going back into town to test that it is getting voltage tomorrow - anyone have the pinout for the 96 fuel pump harness connector? Every diagram I can find online has 4 wires but this has 5.

Hitting with a hammer sadly has no effect this time.

When I think back about what could have gone wrong with install - the only thing I can't recall doing is tightening the nut on the pump body mounting bracket bolt after it was in position. Doesn't mean I didn't, just don't remember.
 
I am going to try direct 12 Volts to the pump before getting towed home - just want to make sure I have the right wires. Anyone have the pinout for the connector at the pump assembly?
 
Also - anyone else having trouble with the site? I am on my iPhone and have Naxja background image filling every white space in the forum table cells. Damn near unreadable.
 
from FSM 96.
6 cavities
#1-relay output(power?) DG/rd tracer
#2-sensor ground Bk/Lb
#3-Fuel level sensor DB
#4 open
#5-low fuel sensor Db/wt
#6-Ground BK
plug
6-5-4
3-2-1
 
Last edited:
BrokenSockets said:
So I replaced the fuel pump, not too hard. hardest part was getting the o-ring to sit still and not poke out the gap while I hammered the clamping ring back in place.

Worked great for two weeks - no starting issues or problems.

Today it sputtered to a stop and died in a parking lot after a long drive and will not start. Fuel pump is not running, no prime noise turning the key.

Maybe I got a bad pump? Something else?

I will be going back into town to test that it is getting voltage tomorrow - anyone have the pinout for the 96 fuel pump harness connector? Every diagram I can find online has 4 wires but this has 5.

Hitting with a hammer sadly has no effect this time.

When I think back about what could have gone wrong with install - the only thing I can't recall doing is tightening the nut on the pump body mounting bracket bolt after it was in position. Doesn't mean I didn't, just don't remember.
Click to expand...


Well, that is a bummer.

Did you replace your fuel filter? If not, replace that thing. And if I were you I would open up the old one and take a look at the inside. See if it is all loaded up. That could be your explanation.
 
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