Hey there we are new to this forum.

My wife's XJ8 with 60k miles started acting out the other day. Coming out of a store the car would turn over but not start. She called a towing service and while she waited tried about 10 minutes later and it started again.

Today she was out and returned with no problems. This evening we wanted to move it out of the garage and once again it turns but will not start. Don't see any abnormal lights flashing and the battery has about 14.5 V.

Anything I can check or would a scanner (OBD2?) tell me what is wrong? Any other words of wisdom? Thanks

Rene

 

Yes:
Make sure you have the upgraded throttle body. Other than that, the crank position sensor is the next likely bet. After that it is just normal trouble shooting. Do rpms show on the tach while it cranks?

 

We bought it in 2005 used and only made about 5000 miles with it since. Besides a dead battery never had any issues so we have not yet been in trouble shoot mode.

Not familiar with the upgraded TB? Any info on that?

Yes the rpm needle moves a little when cranking.

 

Based on that, I'm checking to see if the fuel pump is running. Search threads here for all the info you need.

 

I agree with Jagtech.

Pump is most likely the cause.

 

could also be something as simple as just flooding. 98 and 99 from what i read and experience are horrible with the fludding issue. they tend to flood when started cold and run for a short timespan or trip. mine did this for a few months on and off. all you have to do is depress the gas pedal which will cut of the fuel flow from the pump and allow the fuel in the engine to burn off without more flowing in. turn it over with the pedal depressed for about 30sec usually and then it should start to come to life and once the rpm needle hits over 1500rpm let the pedal back out so more fuel can replace because you have burned off the excess. keep it turned over untill it fully starts. may take another 5-10sec of sputtering before fully starts.

the first time this happened to me i went through the whole thing replaced battery, checked everything from fuel pump to engine and then when i pulled the spark plugs there it was just an overload of fuel. everytime after that when it wouldnt start i just held the pedal and cranked it over untill it started. and thats all it was every time just flooded. hope this helps and if not the problem its still good to know.

 

Not when "about ten minutes later it started again". When they flood, Mr. and Mrs. Motorist are not going to get their car started again.

 

Question, where is the fuel pump? Once you turn the ignition you can hear something running like a pump under the hood to the left of the engine.

 

I guess the searching of threads suggestion is not working, so here is another:

Open trunk
Remove battery cover.
Disconnect negative battery terminal with 10MM wrench
Pull down verticle trim board in front of trunk compartment, secured by two plastic push clips. The gas tank is behind it, and that's what you are going to listen to.
Turn ignition key on to position two.
Stick your head up your trunk, and listen for a high pitched whine, duration two seconds approx, coming from the fuel tank when you reconnect the battery. If you hear the pump run as described, the likelyhood is 99% that you have fuel pressure. If you do not hear the fuel pump run, and you have made certain that the ignition switch was in fact switched on to position two, the likelyhood is 99% that the problem will require removal of the fuel tank to rectify. That's where the pump is: the pumps fail, and even more common is a degredation of the electrical terminal connections to the fuel pump. Try searching threads for "fuel pump link lead", or posts by a guy named "XJ ate". That way I don't have to keep rewriting the same posts.

 

Yeah that one went right over my head. Sorry. Thanks for the tips though.

So what is the whine I hear at the TB when I turn the ignition to two? The whine changes when I move the accelerator by hand.

 

Do you want to ask me any question you can think of, or do you want to get your freakin' car out of the road?

https://www.jaguarforums.com/forum/s...=won%27t+start

 

The throttle motor is what you are hearing. Normal condition with key on engine off. When you hear the noise change that is the motor turning the throttle butterfly in the venturi of the throtlle body. Forget the throttle body, that is not your problem. What you described is a perfectly working throttle assy. Go with what the techs tell you.......fuel, fuel and fuel. No crank sensor, no flooding, no throttle....none of that.

 

Thanks for explaining. Will try to do the sit in the trunk and listen check tomorrow.

 

So I removed the covers inside the trunk to expose the fuel tank. Disconnected the battery as suggested and climbed in to listen. First try I could hear that CD changer and eventually the throttle motor up front but nothing else.

Not sure how loud the fuel pump would be I disabled the changer and eventually the TB motor. I plugged the battery back in and a loud buzzing came from the tank / fuel pump for about 1 - 2 sec. So I plugged the TB fuse back in and started the motor like nothing ever happened.

Any ideas why this intermittent no start happens and why pulling the TB fuse got the fuel pump going again? Any help is appreciated.

 

What you just experienced is the intermittant failure of the fuel pump or the fuel pump terminal connections, which is the reason why the car would restart after ten minutes when it previously would not start at all. The best way to isolate an intermittant fault is to know how to trouble shoot it when it occurrs: that's what I told you how to do, and that's what you just did.

The only further test point is to insure that the terminal connections at the top of the fuel tank are getting power and ground: there is a slim chance that the intermittant feed to the pump is caused by the pump relay , circuit fuse or wiring: retest while checking for voltage to make sure it is getting to the tank. It will be, the problem is inside the tank and you have the full explanation in the attached link to understand why.

The throttle body has nothing to do with it.

 

And if you want "proof", buy a $40.00 fuel pressure test gauge and connect it to the pressure test port. Look for 38-40 psi/

 

It's pretty straight forward it seems, fuel pump was not running, car wouldn't start. Now pump is running again and so is the car. This happened twice now. So as was said it must be the pump or connectors.

I just wanted to make sure that there's no connection between me disabling the TB motor and the fuel pump working again.

Since I do not have the tools nor time to swap the pump myself I'll call some places on Monday. What can one expect to pay to have the pump replaced? Is this something you should have done at a Jag dealer?

 

Yes it is something to be done at the dealer.....bring it to me.

 

Well you didn't give me your address so I had to take it to the local dealer.

I kept driving it since the better half was worried she'd get stranded in traffic. So on Monday I was leaving work early and of course it would not start again. You could not hear the fuel pump buzzing. Had it towed to the dealer and they confirmed it was the pump.

 

Great, I shall consider my futility as having been thoroughly exercised.