1996 X300 - Stalls when Idle
 

Hello,
Just joined forum and checked out several other similar issues. I am not very car/mechanically inclined (damn electrical engineering degree)

Occasionally car stalls when stopped. RPMs drop and stalls. Try to restart and RPMs not enough to keep car going. Usually after about 5mins or so, I can start and works just fine.
If I keep trying to restart right away, it keeps stalling (while not continuously giving gas), it doesn't start and just clicks w/ battery dead, jump it a bit later and starts up just fine.
If I keep gas on after restarting right away it doesn't stall, but as soon as I take gas off RPM drops and it stalls.

Has happened only around 6 times in past month, but usually stuck in the middle of traffic at a light or stop sign, thus not very convenient or popular...

It typically happens within a couple minutes/miles of starting the car. Most times the car was cold, however on a couple of occasions had driven car for 15+ miles, then turned car off, returned after a couple minutes, started fine then stalled a couple minutes later when idle at light/stop.

Took to Brit specialists and they believed it was the fuel pump (although not sure) and got it replaced. $1k and 3 days later and it did the same thing again (stalled at light), twice same day several hours apart

A friend/ex auto mech suggested it was getting a vapor lock and to replace fuel filter. (see from some posts that 96 Jag can't vapor lock...?)
Looking at some posts I see suggestions that it could be the air flow meter.
My Brit specialist believes it may be the throttle body and to try replacing that, but again not sure. (see other post that just suggests cleaning throttle body, not replacing)
His only other suggestion at this point is to drop it off and have them drive it to see if it happens for them and going from there.

Fuel filter seems to be the easy/cheap next step.
Has anybody experienced this and find resolution?
Any other suggestions?

Thank you for your help.
Best,
Tom

Welcome to the forum Tom,

That's a strange model description - the XJ6 Series III wasn't manufactured in 1996.

XJ6 Series III
Attachment 105414

Does this look like your car?

X300 (XJ6 1995-97)
Attachment 105415

When we sort out exactly which model you have, I'll move your thread to the right tech forum.

Graham

Hi Graham,
Thank you, yes it is the X300 (bottom picture). I thought the mechanic referred to it as series III but I must have misheard.
Best,
Tom

Tom,

I've changed the thread title and moved your question from XJ6 & XJ12 Series I, II & III to X300 forum. Members here with the same model will be able to help.

Graham

We had this problem with an X300 once and it turned out to be the plugs. The X300 seems to be very sensitive to plug type. Make sure you're using the recommended Champion RC9YCC or RC12YCC plugs.

The two most common solutions to problems with the AJ16 engine is:

1. Cleaning the throttle body
2. Replacing the TPS

This seems like a #1 problem. It doesn't seem like the throttle potentiometer is at fault here.

I would also recommend looking at the Idle Air Control Valve.

Lastly, could the EGR Valve be giving you some trouble.

I would start with the cleaning. It's easy enough that most anyone can do it? Just make sure to take the time to take the TB off to do the cleaning. Il help prevent damaging the awfully expensive TPS.

Hi Tom,

Welcome to the Jaguar Forums!

Sorry to hear you're having stalling problems. I'm a little concerned that your shop would do something as expensive as replacing the fuel pump without knowing that it was the problem and without first ruling out less-expensive suspects. The pump can usually be tested in place to confirm it is operating and providing adequate flow to the fuel rail.

First of all, did the shop scan your car for any stored Diagnostic Trouble Codes (DTCs or fault codes)? Certain problems will trigger one or more DTCs that will help shorten your troubleshooting.

Aside from the fuel pump itself, there are other suspects, and it's possible that more than one issue is contributing to your problem.

First of all, as Oubadah has asked, how long has it been since your last good tune up (new plugs, air filter, fuel filter, in-tank fuel injector cleaner, etc.)? To answer your question about the fuel filter - yes, change it now as a matter of course. Air filter and plugs too if it's been awhile.

Battery: Jaguars require very healthy batteries, and it sounds as though your battery is no longer healthy. You can have it load tested at most chain auto parts stores for free, but a good independent auto electrical shop may be able to give it a more rigorous examination.

Fuel Pump Relay and Ignition Coil Relay: A failing relay or corrosion on the relay terminals or socket are known issues.

Engine Coolant Temperature Sensor (ECT); the Engine Control Module (ECM) uses the signal from the ECT to determine cold start fuel enrichment. When either the sensor itself goes bad, or there is an intermittent problem with its electrical connector or wiring harness, the ECM may apply an incorrect fuel mixture for the temperature of the engine. The ECT's operation can be tested with an ohmmeter, thermometer and pan of heated water and comparing its resistance at various temperatures to the chart in the Engine Management Systems manual, but a basic test is to check its resistance when the engine is cold, then again when the engine is at operating temperature.

The Intake Air Temperature sensor (IATS) is also involved in cold-start fueling, though as far as I know reports of them failing are rare.

Idle Air Control Valve (IACV), which is operated by an electric stepper motor. The valve itself can plug up with oily gunk, diminishing the ECM's ability to control idle rpm; the stepper motor electrical connector should be checked and cleaned. The stepper motor can go bad, but I don't think that is all that common.

Throttle Position Sensor (TPS): The TPS is mounted to the throttle body and is subject to wear and to contamination by oil & other gunk. The TPS signal is critical and is used by the ECM for fueling, coordinating with the Transmission Control Module (TCM) for smooth gear shifts, etc. I'm not sure this is your primary problem, but it could be a contributing factor.

Exhaust Gas Recirculation (EGR) valve stuck?

Fuel Pressure Regulator (FPR): Works with the fuel check valve to maintain proper fuel pressure in the fuel rail. When the diaphragm in the FPR fails, unmetered fuel is inhaled into the intake manifold, enriching the air-fuel mixture but bypassing the ECM's control. You can pull the vacuum hose off the FPR, crank the engine and check for the presence of wet fuel at the vacuum hose fitting on the FPR.

Low transmission fluid is sometimes associated with stalling when coming to a stop or slowing to make a turn, so check your fluid level and condition when Hot. I don't think low transmission fluid would make your engine difficult to restart after a stall, but perhaps it is contributing to the stalling and another issue is contributing to the hard restarting.

I'm sure other members will have more ideas.

Cheers,

Don

The plug thing isn't just about age by the way. We wrongly assumed that we'd covered the plug base by installing new NKG plugs, and were investigating elsewhere. After an expensive and time consuming wild goose chase we finally put RC9YCCs in it and it stopped stalling.

preventive maintenance of engine
 

The model X300 is almost twenty years, properly maintaining the engine is a must to keep it on tip top condition, tune up is not only changing spark plugs, it must include the cleaning of injectors and contact cleaning of ignition coil with correct electronic contact cleaner, throttle actuators must regularly be cleaned as well by using throttle actuator cleaner (i personally recommend wurth brand) as the saying goes "an ounce of preventive is better than a ton of cure".

It is not difficult to clean your injectors, will post on how to proceed without any fancy machines or bench.
removing injector is straight forward, making sure you spray first with lubricant (WD40 and the like) on the outer orifice between the rail / engine cylinder head and the injector (inserted O rings on each side of the injector.

Your cat will feel the pur and power again.

Also it wouldn't hurt to change the coil shaft seals as mine wore out a month ago and oil filled the shafts as well as filled a crack in a plug which a crack is obviously bad by its self. but you didn't say it sputtered and no spark means raw gas out of the exhaust so most likely your throttle body needs a good cleaning.

Replaced plugs w/ RC12YCC but stalled again
 

Hi all,
Thank you everyone for your suggestions, VERY MUCH appreciated.
I replaced the NHK plugs with RC12YCC's last weekend (several posts had this fixing the problem), ran fine for a week then stalled again yesterday.
Started it up, depressing accel and started but then stalled when taking off the gas. Waited a min and started fine.
The stall triggered the Check Engine and Transmission Failure indicators and is in Limp Home Mode. (happened before and once fault cleared no issue w/ trans)
A friend with an OBDII scanner is coming over to clear the fault and then change the fuel filter (air filter is clean).
From there will clean throttle body and other tune-ups, then move on to other suggestions if needed (TPS, etc)
Thanks again for all the help.
Best,
Tom

Did you ever resolve the issue?

Not sure if resolved yet, it sometimes takes weeks before it stalls.
2/9 cleaned around the throttle & replaced fuel filter.
2/14 stalled once when starting, but started ok a min later
3/5 stalled 4 times when trying to drive home, 4th time it wouldn't start (just clicked), got jump and started ok, cleared the transmission fault w/ odb2. Got home after 30+min drive and wouldn't restart. Jumped & was getting 14.2V while running, so alternator appears ok.
3/6 replaced battery (was apparently > 12 yrs old) and added fuel cleaner.
Running ok since, keeping my fingers crossed.

That old battery could have been the real problem. The electronics do not tolerate low voltage, and at idle the alternator may not have been able to over come the effect of a weak cell.

a full and complete tune up includes cleaning the EGR, the fuel rail, fuel regulator and fuel injectors.

My car recovers just before it stalls. At the very last millisecond the stepper motor wakes up and saves the day. Just wish it would kick in a bit quicker.

Thank you to everyone who offered suggestions. Very much appreciated.
It looks like the battery did it. Made it 5wks now without a stall.
Tuned up a lot of other things along the way, and running nicer than it has in a while.
Best to all,
Tom

Thanks for the happy update!

Glad to hear the positive results so far. It's true, the more effort in hunting down a problem, the more things you can check, clean, and correct along the way, usually for little cost. Sounds like your battery was totally shot. Another relatively simple fix (once you replace the right item)!

This is another great example of the team pitching in with great suggestions. DonB "wins" the diagnosis as he first mentioned the battery in post #7. Although he had an unfair advantage, because he took the time to share lots of his vast knowledge! AWESOME Don!

Spark plugs; battery; CKPS; TPS; fuel pump; contaminated fuel; fuel injectors; coil packs; sensors; loose/corroded connections etc. etc. All things that need attention eventually. Oh, the ways in which we "suffer" for the love of our old Jags...

I thought this thread would help with my '95 X300 issue. It started lurching and nearly stalling when starting from rest. No new codes on reader. It's running almost like transmission problem, but when it revs up, it runs smoothly, from about 1500 rpm up. Any ideas?

Start at the beginning of the list Steve! The engine is sensitive to spark plugs and demands a juicy battery. I had those same symptoms you describe when my CKPS went bad. If it hasn't already been replaced, it should be. An easy DIY job at least. Cost around $100 US.