pos93

Hey guys how's it going. I've been having some trouble figuring out why my xj won't run. One day it just died while driving. Started right back up then kinda stumbled and bogged down when I hit the gas. I've replaced the cps, tps, iac, and the map sensor and got nothing. It's idles fine for about 10 seconds then the idle gradually goes down then it just dies. And when I hit the gas it boggs down a lil. I even replace the fpr cuz I thought it was running too rich. Any suggestions you guys got I'm all ears cuz I'm stumped on this. Thanks jeff

Gmaster

Check the fuel pressure, sounds like it may be to low

XJ RYAN

I would change the fuel filter then check the pump next

tjwalker

Fuel is suspect.

I agree that a fresh fuel filter is in order. After that, you MUST verify fuel pressure with a gauge. It is the only way to verify proper fuel delivery and that needs to be ruled in or out early in the troubleshooting process.

Many big box parts stores will rent you a fuel pressure gauge. Call around.

Good luck!

pos93

Put on a new fuel filter 2 weeks ago. And yeah I'm checking the fuel pressure tomorrow. Hopefully that will be the problem. It's just kind of weird cuz it starts up right away like the pump is fine. Thanks guys I'll update this tomorrow after I check the pressure.

elalr

i have the exact same problem!! new pump about 2 weeks ago also!! i checked my fuel pressure and i only had 10 max 7 at what u might call a brief idle before dying. mine holds no pressure with the key off. im replacing the pump again but im suspecting the regulator! my other xj holds over 10 after sitting all night and some bleeding off while hooking up the guage. i ask this before but got no response. could the regulator be stuck wide open. believe thats my true problem and others with hard starting issues. if it leaks off quick it wont be there for initial atomization at the injector for starting. sorry to ramble but i hope you find your problem. i will post my findings on mine

pos93

That's what I thought too. That the regulator might be stuck somehow. Or even the iac valve itself. But I replaced the regulator and rebuilt the tb and got nothing. So yeah man let me know what's your fix.

pos93

So I tested the fuel pressure today. It pressurized at 18 psi max, then as it ran it gradually decreased till it died. So I guess I need to get a fuel pump. Thanks guys for the help.

freegdr

was it a quality filter you put on it 2 weeks ago

Gmaster

It shouldnt matter if the filter was the cheapest one they have, its not going to restrict that much. Just sayin

pos93

I forgot the exact name. But It was a generic filter from napa. But yeah there's no way it would restrict it that much in 2 weeks. No matter how ****ty the filter

elalr

got my fuel pump on and its running normal again. before taking the last one back i inspected it and found the hose clamp on the outlet of the pump was placed above the barb so it wouldnt hold or build pressure. good luck on yours.

pos93

Put in a new pump and strainer in today. Still runs the exact same as before. I'm seriously completely stumped. I have no idea what could be wrong with this thing. Any suggestions?

tjwalker

18 psi is your problem. This is a confirmation that you need to shop for a new fuel pump.

Try to find a Bosch. Do NOT buy an Airtex. Way too many problems out of the box with that mfg.

pos93

Already put in a new Bosch pump 20 minutes ago along with a strainer. Same exact thing. Read above post