i have heard of probs with the hose clamp in the tank being loose but the pressure is def wrong

 

drove the truck today and it had quite a bit more power than before. I noticed that when i floor the car it starts to accelerate with a nice pull and then just kind of bogs and does not accelerate as brisk. But it seems that less gas i have in the tank the better it gets.

 

that dont make no sense

 

have you done any thing prior to the problem new gas cap mess with the evap system im searching

 

I got the trucj with bunch of issues. already spent 2k on all little things fixing it up. I got the truck with half of the vacuum lines missing, cracked header and cracked intake/exhaust gasket, clogged cat, rusted exhaust, leaking fuel pressure regulator, bad plugs, wires, cap and rotor. So i replaced all of those things which made the car run a million times better.

Before it would barely idle and had pretty much no power at all. Now it just has that intermiten lack of power when accelerating. I am pretty much convinced that the fuel pump(or at least the drain back valve) is bad on it.

 

the pressure sure is not right

 

Ok, so I am going to buy a new fuel pump but I don't knownif I should buy the whole pump sending unit or just the fuel pump and the strainer. Is the fuel pump check valve built into the pump or is it a saperate piece? I want to make sure if fix this right the first time.

 

Which line is the return line? I am starting to doubt myself here. Is the return line connected to the fuel pressure regulator or comes off the back of the rail? It says I have to pinch the return line, if the return line is the metal line coming off the fpr, if I pinch that it won't ever "unpinch".

 

i would think the return line will ahve less pressur so i would say its rubber

 

That's what I thought. And fsm says pinch the line and the rubber one is the only one that can be pinched.

Is fuel pump check valve part ofthr pump or it's a separate device on the sending unit?

 

Replaced the whole sending unit today and it totally fixed everything. As soon as I started the truck fuel pressure went up to 32psi and when I shut the ignition off it stayed there for quite a bit of time. Truck starts great now. Only cranks for a couple of seconds. And no more lack of power, pulls hard.

 

I just replaced my fuel pump because it had started to try and pull its "I'm not going to come on and prime when you switch your key to the on position unless you disco the battery" trick for the past week. But I didn't realize how many other issues it was having because of it. Throttle is smoother, idle is smoother, engine is quieter. Although now I'm sensing that it's running rich. May have to replace some sensors or put in a high mileage chip or something to manually handle the air/fuel ratios.

 

Good thing you got it right...
Just make sure you've a good TPS and a working o2.

and the no-return / check valve is inside the fuel pump.

 

Most sensors on your XJ can be tested with a manual and a meter.

TEST them before replacing them. No sense throwing money away......
Oxygen sensor, coolant temp sensor, map sensor contribute to the fuel air mixture.

Skip the chip. Not a good strategy. If you are running rich, find the reason why and fix it.

 

Running rich is probably due to a bad oxygen sensor. 1st thing to check in my opinion.