Starting Issue 01 XJ

I have an 01 4.0 XJ with 104k miles.
Recently when trying to start the Jeep its will crank and sound like it will fire then its will stop firing and the starter will continue to spin.
Usually this only happens on the first start and then the second try it will fire up just fine.
Sometimes its is worse then others and will not start at all and will continue to do the same crank then stop. It will also sometimes backfire and make a big blowing sound coming from the intake.
I am thinking it may be the cam position sensor.
any input helps.
Thanks in Advance!

You have a failed fuel pressure check valve on the fuel pump or one or more leaky fuel injectors. The failed check valve is very common on the 97-01.

Interestingly, when my 2000 has the same symptoms, a fresh set of Champion spark plugs will make it stop backfiring and making the whoosh sound. (My check valve still needs to be fixed).

Priming the fuel system will help the engine start faster. Turn the key to ON, wait 3-5 seconds. Turn the Key to OFF. Turn the Key to ON, wait 3-5 seconds and then attempt to start. The key on-off trick usually results in a start on the first attempt.

thanks for the help!
Is there anyway I could check to see if I have leaking injectors?
Where is this check valve located?

Any check engine light? If so, pull codes.

Extended crank time can often be the check valve on the fuel pump (inside your gas tank) but the symptoms you mention (backfiring/whooshing) when it fires leads me to believe that something else may be going on.

If it were mine, I would want to perform some comprehensive fuel pressure testing using a good fuel pressure gauge and following Jeep's recommendations; there is a very detailed fuel pressure testing procedure in the Jeep Field Service Manual. (not Haynes or Chiltons) Fuel pressure testing may tell the story. It's the place to start anyways.

Test your way to a solution. Don't guess and or throw parts at the problem.

Check valve is inside the gas tank. You have to drop the tank and pull out the fuel pump assembly. Some people have added valves from other vehicles in the fuel line. If you try a search, you may find where joe_peters (IIRC) has added BMW valves into fuel lines.

When you say "crank and stop", are you saying that it keeps cranking strongly but stops trying to start, or that is stops actually cranking the motor, but the starter continues spinning?

My 99 stalled a couple times and then refused to start at all one week.

It would crank but not start.

I saw a message pop up in the odometer that said "no bus".

I researched it on this board, and it turned out to be my CPS. Crank positioning sensor.

I bought a new one, put it in. and it started right up and ran like new.

Hope this helps

Now the jeep wont start at all. The starter spins but it does not seem to turn over the motor. I also noticed while looking at the injectors the the 1st injector(closest to front of car) is cracked along the shaft part of it. I am assuming this is a potential problem. I am not seeing and sort of leak from the injectors but the crack doesnt seem good.
Also if I was to replace injectors on my 2001 would the Ford 5.0 injectors work? and if so what are the exact model # or part # for those injectors or any other injector option?

Thanks

If the starter spins, but doesn't turn over the motor, there's where your problem is. Most of your local auto stores should be able to test it, but those tests don't test em on load, however it can spot a bad solenoid fairly easy. You can try giving it a love tap with your hammer, but that's not really a good way of doing things. I'd check the cables to the starter first, make sure they aren't toasted.

ebjones7 said:

I have an 01 4.0 XJ with 104k miles.
Recently when trying to start the Jeep its will crank and sound like it will fire then its will stop firing and the starter will continue to spin.
Usually this only happens on the first start and then the second try it will fire up just fine.
Sometimes its is worse then others and will not start at all and will continue to do the same crank then stop. It will also sometimes backfire and make a big blowing sound coming from the intake.
I am thinking it may be the cam position sensor.
any input helps.
Thanks in Advance!

Click to expand...

Well not sure if you're trying to describe a starter problem, or a hard-starting and misfiring problem.

Does the starter motor free-spin after the motor starts, dies and misfires??

First and foremost, try using Chevron Techron fuel additive to assure you have clean fuel system. And change the fuel filter....

Second, make sure you don't have a leak... pressure test the system. I've had two leaks emerge in 170K miles.. both right over the header pipe. I'm lucky my XJ doesn't look like burnt toast.

Third, mine started this business of taking a long time to start... first crank, nothing... second crank, something... third and forth crank it would finally start -- no belching tho.

Anyway, I finally smelled a gas leak... this was last week BTW. So I pulled over and lifted the hood and there was gas pouring out of the fuel pressure regulator (right on the header) where the vaccum line attaches...

Needless to say I had it towed in... had the dealer replace the fuel regulator gasket and performed a fuel pressure test and found my fuel pump was weak... which I knew was on its last leg anyway...

I've also had the high pressure fuel line spring a pinhole leak before... and found it spraying on the header pipe as well...

.

ebjones7 said:

Now the jeep wont start at all. The starter spins but it does not seem to turn over the motor. I also noticed while looking at the injectors the the 1st injector(closest to front of car) is cracked along the shaft part of it. I am assuming this is a potential problem. I am not seeing and sort of leak from the injectors but the crack doesnt seem good.
Also if I was to replace injectors on my 2001 would the Ford 5.0 injectors work? and if so what are the exact model # or part # for those injectors or any other injector option?

Thanks

Click to expand...

Two possibilities (actually 3). One is the starter clutch could be fried. The other one is the teeth on the starter and/or flywheel. You need to pull the starter and take a look. Look in through the starter opening and check the flywheel teeth. Look at the starter teeth. If that all looks good, turn the gear on the starter by hand. If it free wheels, the starter clutch is shot. Of course, this all assumes that the starter is actually bolted properly into place, not like one guy who posted that his was held in place with a coat hanger.