Qcollons

I just changed the fuel pump on my 91 ls 400, drove it 4 3 days and when I stopped at the store it didn't start... I had the new pump tested and it works fine, they said I'm not getting fuel to the pump ... what could b the problem ... 1 luv

LiCelsior

iTrader: (32)

clogged fuel filter?

deanshark

To the pump?? It would have to be the filter on the bottom of the fuel pump being clogged. That would be the only thing between the pump and the fuel itself. Do you have any enemies that would put something in your tank? If that filter is clogged I would suggest draining the tank and cleaning the tank out the best you can.

sam12345

iTrader: (1)

Maybe emission issue so tank is under vacuum?

Qcollons

Could it b the fule pump relay

deanshark

Well, you said the pump was tested and it's working fine. If the relay was bad then the pump would not turn on at all. Who tested it? Was it tested in the car where they just heard it turn on or was it bench tested to make sure it pumps enough in and out?

One way to check if the pump is working, while in the car; In the diagnstic box in the engine bay you connect terminals +B and FP with a jumper wire, turn key to on, (do not start) check if the little screw on top of the pulsation damper jumps. If it jumps your pump is working and you'll have pressure to at least that point.

FrankReynoldsCPA

This is probably less likely, but you could even have a clogged line. I don't think that would happen though unless your car sat for a while and accumulated crud in the tank. Happened with our motorhome on Memorial Day weekend. It had sat for 5 years in our backyard. We got about 80 miles up the road, and it just started cutting out and loosing power until it finally gave up the fight and died on the side of the road. We determined pretty quickly that the engine(this is an 88 Chevy 454 with a carbuerator) wasn't getting fuel, so we checked the filter, it was clear. We checked our fuel pump, it was functioning properly. We had my uncle come by with an extra electric fuel pump. We wired it up and hooked it to the line from the tank to the filter, and left it open on the output side. Turned it on, nothing was coming through the pump. The tank was just over 1/2 full. It was pretty clear that the line was plugged. So we did what most professional mechanics would do. We grabbed a couple of gas cans, stuck them inside the motorhome, ran our new fuel line from the engine to the electric pump, and into the gas can, had my uncle hold the cans while my dad drove. I followed behind in case they died again. Ran fine. A while down the road i saw fuel leaking pretty fast underneath the coach. We stopped and I noticed that fuel was now flowing out of the line again. I guess pressure from the return line and all of the movement from the motorhome managed to dislodge whatever was stuck. We hooked it back up and it ran fine again.

deanshark

Oh yeah, been there. We had an old VW Thing we used to haul logs out the woods, ended up getting a hole in tank. The passenger had to hold the can with his feet, splashing gas all over as we baja through the woods and still in there smokin a bone. Gotta do what ya gotta do, it was nice being young.


Try pulling the fuel line off before the filter, turn the key, just for a second, see if anything comes out. Then you know which way to go, either back towards the tank or forward towards the injectors. No matter what you should change the fuel filter that's in the fuel line.

sam12345

iTrader: (1)

Not sure if this will help

https://www.clublexus.com/forums/ls4...m-problem.html

https://www.clublexus.com/forums/ls4...-pump-ecu.html

LEXTEK1

That little rubber hose from the fuel pump to the fuel line may have split or come off. Inside the tank. Just a thought!