squatchbeard

ive got a 2000 xj sport thats been giving me a hard time starting this winter. it turns over but wont get going. my dad says it sounds like its not getting enough feul and thinks maybe the feul pump but the feul pump is only about a year and a half old. this morning it started and shut off immediately, and did this about 3 or 4 times. it takes me 3 or 4 times to start it on a bad day, and on a good day i dont have any issues. any ideas would be helpful.

Roler

it could have everal causes, so a bit of diagnostics can help. What you can try is the following: turn the key to the on position, you should hear the fuel pump prime for 1 or 2 secs, turn the key to off position again. Repeat this three more times, than start the engine. This way you prime the fuel line/pressure and if you find it starting straight up, than yes it could be ur fuel pump getting tired. there r also fuel leakback valves involved in this, but those issues can be sorted out later with a fuel pressure gauge. see if this improves anything and let us know.

slimjim9059

I'm going to give this a shot. I know mine takes what seems like forever to crank over. But once it starts, its fine. If I turn it off and right back on, it stats right up. If I go into 7/11 and get a drink... it takes a few seconds, if I let it sit for like 15 minutes, it goes back to the original starting time of forever. That's not 100$ accurate but it does scale like that. I guess that could be more of a vacuum leak?

docmedpros

start with fuel pump like Roler said, then work your way through the system.

Roler

The next step would be using a fuel pressure gauge at the fuel rail. Pressure drop '"characteristics" when engine is shut off can lead the way in diagnosing other causes for the difficulty in starting where fuel pressure is an issue, such as fuel ' leak' back valves that fail (I believe there are 2). But will get to that if needed (plenty of info in threads on this btw, do a search).

scheetz_21

yes could be the leak back valves! my buddys did the same thing.. replaced it and fires up like normal. before it crank all day unless he primed it a few times.

squatchbeard

ok ill try to prime it before i start it from now on until i find out for sure what the issue is. thanks guys.

tjwalker

You really need a fuel pressure gauge to tell you if you have proper fuel delivery.

If you don't have access to one, you can rent them from many parts stores.

For your vintage, you should have 49 psi, plus or minus 5 psi.

It will take you about 10 minutes to confirm this. Do it.

Roler

I thought to teach them your poor man's prime TJ, as a diagnostic-wihout-equipment the pressure gauge is ofcourse the data collector.

tjwalker

Roler.....the "poor mans prime" is for sure a good no cost diagnostic technique!

But for a vehicle that dies after starting, I think I'd get a fuel pressure gauge on their and see if you can watch the fuel pressure fade as the engine stalls...

Roler

Absolutely true. Must have missed the shutting down after starting that was mentioned, besides the starting difficulty itself.

squatchbeard

the priming helped a bit, i used a fuel pressure gauge and im only at 35 when idleing. when i shut the car off the pressure holds. any ideas?

tjwalker

The spec for fuel pressure on your 2000 XJ 4.0 is 49 psi at idle, plus or minus 5 psi. 35 psi is not going to cut it.

I highly recommend you replace the entire "fuel pump assembly" (pump/regulator/filter) while you have the tank down. Tank must come down to replace yours.

My favorite brand of fuel pump for the XJ is Bosch. Carter is okay. I will not install nor will I recommend Airtex.

squatchbeard

ok thanks tj ill do that plus its tax time so im looking into lifting this mother up and putting 30s or 31s under a 3.5 inch lift. maybe ill get all the parts and doo it all in one weekend. thanks for the advice and help everybody ill update when i install the feul pump assembly.