New owner here.. purchased a 98 Xjr with 140k last month and have really been enjoying it so far. The car dies 2-3 times per week (400 miles). Mostly at startup but sometimes while cruising down the road. I was going to replace the plugs and do a fuel filter. Is there anything else I could check or replace? Its pretty funny the car actually says ''stalled'' when its happening while driving. Ran one tank of cheap 87 and 2 tanks of Sunoco 93, no noticeable difference. Thanks for any help

 

Hi X308XJR,

Welcome to Jaguar ownership and to this forum!

A new fuel filter and new plugs (properly gapped) should be a good start. Air filter too. Also, check the level and condition of your transmission fluid: low fluid is sometimes associated with stalling, believe it or not. Follow the procedure in your owner's manual carefully to check the fluid level when the transmission is hot from a drive.

If you still have the problem after doing those services, it would be worth replacing is the fuel pressure regulator, which is supposed to maintain the pressure in the fuel rail, but over time it loses its ability to do so, which can lead to intermittent fuel starvation.

Cheers,

Don

 

It's funny you asked about the fluid as I had an issue with a trans line going into the radiator contacting the serpentine belt..well 6 and a half quarts later and I'm just above the 80c mark on the aftermarket dipstick when hot..So fluid is good air filter new. I'm going to order plugs and fuel filter and try to get a fuel pressure gauge hooked up. Any suggestions on plugs/gap?

Also just after I posted I took off the intake tube and cleaned the throttle body while rigging up the throttle blade fully. Wasn't really dirty but we will se if it helped. What I did notice was the throttle blad wasn't even close to WOT so I adjusted it to just below where it makes contact and big difference in response and shifting. At first idle jumped form 600 to 1200 but I took it for a road test and it seemed to settle back to 600...should I adjust it till the stop and the ecu readjusts?

Sorry for the drawn out response but I really appreciate the help.

 

You might check the workshop manual, but I believe the throttle blade (or butterfly valve or disc) is supposed to be adjusted so that when it is fully "closed" there is a gap of 0.002 inches between the edge of the butterfly valve and the throttle bore.

The accelerator cable should then be adjusted to remove all slack (without increasing the idle rpm), and ideally at WOT the throttle will open all the way to its stop screw at the same moment when the accelerator pedal contacts its stop button or depresses the kickdown switch (not sure which your car has).

BTW it's the back side of the butterfly valve that gunks up with black crust - are you saying the back side of the blade and the throttle bore behind the blade were clean?

Regarding plugs, see the thread at the link below for advice from my friend from Down Under, xjay8:

https://www.jaguarforums.com/forum/x...rk-plug-91496/

Regarding the transmission fluid, over-full fluid can sometimes contribute to stalling also, so if you're much over the hot line, you may want to try removing a little fluid with a cheap fluid transfer pump. Even a pint over-full (or low) can cause issues.

Cheers,

Don

 

Sounds as though I adjusted it a little too far than, I'd say I have a gap of about a 1/16th of an inch between blade and bore but even than there is still about an 1/8th of an inch before it hits the stop at WOT with that switch at the bottom of the pedal being pressed.. I guess the only way to really see what's going on is to get a scanner on it...

Good link on the plugs as long as xj8 and r use same plugs.

The backside of the throttle blade wasn't perfectly clean but there was no serious buildup. Either way that is clean now..

 

I checked today with a scanner and off throttle was around 3% absolute throttle position. WOT was about 85% and when I stepped that extra bit and heard the switch click I was at 98%. Only thing I dont like is I can feel it pulling in drive when I have my foot on the brake like im putting extra stress on the transmission. Idle in neutral is still 600 but in drive on brake its around 650 id say..

 

Clean the throttle body and the MAF sensor. They use different cleaners. When the plugs were out look for oil. The covers tend to leak and will cause misfire. Check for
gunked up breather hoses. A computer reset may help after doing all this. The engine
computer will try to compensate for issues up to a point. Reset puts it back into mid range. Look around for any hoses that are old or damaged. A vacuum leak on any engine will cause erratic operation.

 

When cleaning the the throttle body, spray some cleaner down the idle bypass passage as well.

 

check that the electrical connectors are not the mismatched gold on one connector and tin on the other ... there was a TSB on this for the random stalling

also check that your brake fluid is not too high. someone solved a random stall by fixing an overfilled brake fluid reservoir.

 

When my XJ started stalling at start up, it ended up being the fuel pump needed to be replaced.