philwarner

96 Country straight 6. Both fuel pump and gas gage stopped working and the old pump had no continuity and a gunked up screen so I bought a used assembly from another junk yard 96. The "new" pump is a replacement Walbro GSS239 "Made in USA" pump. I tested the pump before putting the assembly in and it pumped fine and the gas gage and the pump worked for about a week and then the pump quit priming so I took it out again and put it in a tub of gas and it pumped like a champ. The screen had some grey gunk on it so I brushed it clean and also siphoned several gallons out the tank bottom through the pump hole. Put it back in and it again worked for another week and then quit again. Took it out again and back in a tub of gas it pumped like a champ. This time I cleaned all the internal spade connectors and ran it from wires pushed into the pigtail connector to make sure the pigtail wiring was OK. The screen was just a little dirty so I siphoned the tank out again and got just a little more brown stuff this time. Put the assembly back in and it worked like a champ for another week and then quit priming or running while cranking again.

I've checked the pump relay, made sure the harness connector gets 12V for the prime period, sprayed both connectors with contact cleaner, and even run the pump in a tub while connected to the car wiring to make sure it primed and ran both times before I put it back in and each time it lasts a week and then I hear it make a short groan when I turn the key on and then it stops priming or running.

Does anyone have any ideas before I pull that sucker out again? When it runs it draws about an amp and in the car it pumps 49 PSI on the nose like it is supposed to - until it quits after a week.

BlueRidgeMark

It's either a wiring problem in the vehicle or it's just getting clogged. If it's wiring, check your grounds. #1 cause of strange electrical problems. Then work your way back from the pump through the system and look for broken or corroded wires.

If it's getting clogged repeatedly, drop the tank and clean it thoroughly.

philwarner

Thanks for the reply. Yeah, I was hoping to avoid dropping the tank. I looked at the bottom with an inspection camera but couldn't tell much. I'll try driving the pump in place from an external battery and if it still doesn't run it is probably tank time.

BlueRidgeMark

Sounds like a good plan.

Dropping the tank really isn't that bad, though. The worst thing is that your J-bolts sometimes have to be cut off, and the replacements are stupidly expensive.

The good news is that there are a lot of other options. There's a thread around here someplace where people talk about good alternatives to the expensive factory bolts.

nujeepguy

i never saw the pump. is it access from the top?if so how would it be ezer to flush when out?.drain on bottom?. im just guessin since idk the tank and its too cold and rainy to go look!

djgrayxj

Note from DJ
Cheap Gas Tank Strap Bolt Fix
https://www.cherokeeforum.com/f2/che...lt-fix-114357/

BlueRidgeMark

I think 97 was the year of the new tank style, where the pump access is on top, instead of on the side. The only way to clean it out is to drop it, remove the pump, and get to work.



Oh, yeah! DJ to the rescue! That's exactly the thread I was thinking of!

philwarner

Update: Today the fuel pump groaned twice and then was silent when I tried to prime the fuel rail so I put an external 12V battery on the pump's pigtail connector and it ran and drew 4 amps but there was still no pressure at the fuel rail so I replaced the fuel filter. (and there was some rusty gas in the old filter inlet). I used the external battery and a length of fuel hose to pump 9 gallons out of the tank to empty it. I used a clear bottle and pumped 1/2 gallon at a time and it all came out clean and the pump drew less than an amp when pumping with no back pressure. I poured the gas back in the tank and reconnected the fuel line and pump pigtail and then the pump primed and the engine started and ran with 49 PSI at the rail; the pump drew a steady 4 amps. So...is 4 amps the usual draw for this fuel pump?


Since the pressure regulator is in the tank and there is only one gas line to the engine and no return line, I am thinking the pump should have run even if the filter was plugged, so I don't know if a new filter fixed it. It also is not holding pressure when the pump is turned off, so there is still a problem with the valve on the top of the pump. I am going to let it sit and try the pump every day to see if it stops running in a week like before. If so I'll have to decide whether to drop the tank, so thanks for the link to the replacement bolt thread - I'll keep spraying the bolts with PB Blaster in the mean time just in case.

nujeepguy

ill stick my neck out. pump it out or siphon.dump in soapy water and scrub.fill with water,vac it out. being careful. vacumes creat sparks!!

philwarner

It primed and started OK this morning so time will tell.

BTW, I've heard stories of folks using shop vacuums around engines and blowing them up because of sucked in vapors. I'd bet that is a nasty surprise.

EDIT: I drove down to the boathouse and the fuel pump seemed OK but the gas gage showed empty with the fuel light on both ways and I know it has 9 gallons in the tank. Just after I re-filled the 9 gallons the gage read just under a half tank and later just above a quarter: it had been slow to rise before and now it does not rise at all. Bad Ground? Poor connection at the pigtail plug? This Jeep is driving me crazy.

DFlintstone

X2^. Even a well sudzed and rinsed fuel tank still has volatile vapors that can explode. Even full of water except for the small corner you are welding/brazing. (putting a spigot on an old Jerry can for example)

philwarner

Several years ago a fellow was welding on a marina repair barge at a boat ramp we can see from our deck when the barge blew up. (fortunately we weren't watching at the time). There was a young girl who he had hired to help him the day before who was standing on the barge and the blast threw her 20 feet into the air and killed her. He probably thought the gas tank was clean too.