With my 95 XJ6 I have been experiencing an engine stall after stopping at a red light. It happens after the car has been at idle for about as long as a red light stays on. When it stalls it is sudden like the switch was turned off. Going to park and trying to restart works every time without fail. Sometimes it won't quite get to zero rpm and it will restart by itself. It did it three times today on about a 40 mile trip with several stops. On the way home when I had to stop at a red light I would put it in neutral and pulse the throttle slightly now and then. No more stalling doing that.

What suggestions do you have. I do need to clean the throttle body. Is there a sensor inside the TB that is dirty and loosing it's signal after a short time at idle.

Thanks for your help.

EZDriver XJ6 1995

 

A nice clean throttle body will allow some air to flow by at idle and a nice clean idle speed valve will allow for quick adjustments for different engine demands (e.g. Air Con pump kicks in).

So I suspect your stalling is due to asphyxiation rather than a sensor.

Next time you're at the red light, cover your nose and mouth with your hand and see how your engine feels

 

Thanks for the input B1mcp. Cleaning the TB is next on the list. I assume removing it is the best way. It looks fairly streight forward. Do you have any tips that you have developed with your experience that would keep me out of trouble?

Thanks again. I can always depend on you guys.

EZDriver 2000 XK8 1995 XJ6

 

Yes it is best to remove the throttle body for thorough cleaning. It is all very straight forward. You might want to have a new gasket available although you can normally get away with re-using existing gasket.

Use Carb cleaner to remove the gunk. There is a section in the X300 Book on the Jag-Lovers.org website that would be worth a quick read before you start.

 

EZdriver, the throttle body on that car does not have a gasket! It is polished metal, so just make sure its clean when you put it back on. Furthermore, the removal is pretty straight foward, although to take it completely off you should get two clamps and clamp the coolant lines that run underneath it to prevent a mess and save some fluid! Also, youre stalling problem may indeed be a sensor! I had this same issue with my 96 and it turned out to be a bad tps! But clean the TB first, i did and it didnt resolve my issue and so i moved on to the next possibility. Start with whats free, cleaning your tb is free. Buying a new tps can set you back 280$!! Hope it works for you!

 

From etaent - EZdriver, the throttle body on that car does not have a gasket!


Absolutely right. Sorry, I was thinking XJ40.

 

Thanks for your info. I assume that tps stands for throttle position sensor. Could you tell me where that is located?

Thanks again.

 

the tps(Throttle Position Sensor) is located on the lower portion of the throttle body. Its right by the two coolant lines. Now when you clean your throttle body, be very careful not to get TB cleaner on this sensor. TB cleaner is very potent and can eat away at plastic, over time this can cause issues with your sensor. But first i would clean out your TB and get a contact cleaner and clean the contacts that goto the tps, the idle air control valve(IACV) and your Exhaust gas recirculation valve(EGR).

 

Be aware......

On the X300 AJ16 engine, if you tamper with the throttle body settings or clean it, the only way to be sure it will run CORRECTLY again, is to have the throttle potentiometer adaption reset with the Jaguar PDU or IDS diagnostic equipment. Base butterfly setting has to be .002 inches.

Based on the OP's description, that may be all the car needs to correct the stalling.

Good luck!

 

Xjrguy is right. That's something I forgot to mention. An engine setup would be necessary

 

So if I just clean the TB and the idle speed valve I will have to go to a Jag shop to have the darn thing re setup?

 

Unfortunately, to prevent constant, weird idle problems, yes you do. The ECM adapts to the very slow buildup of coke in the throttle bore to correct the idle. It adds air that gets choked off and no longer goes around the butterfly. When you clean and adjust it, all that air comes back and it idles strangely, usually pretty fast. It has to be reset so it controls the idle air valve right. Way too many people overlook that. They try to compensate by adjusting stuff and make matters worse.

Lots of these AJ16's are running around like that.

Cheers,

 

Great since I'm one hundred and fity miles from the nearest dealer. With a good Indy, which I have, can't we use his diagnostic equipment to do this readjustment on the idle speed.

 

I feel for you, pal. There are only three pieces of equipment that I know of that are capable if that:

Jaguar PDU, WDS and IDS. Whoops, there is #4, a GenRad GDS510 handheld. And for some reason, once in a while, IDS or the 510 won't get it done on some cars. Then I have to resort to one of the other two.

You could try and hunt for an Indy that might have access to some Jaguar equipment, there are some out there.

Happy hunting!

 

Also, there is a sensor in the main induction pipe immediately down stream of the air filter. It is in a section of the big diameter pipe and inside it looks like a section of a wing with a pipe sticking forward right up to the screen. Could you tell me what that is and what it does. It cannot be taken apart to clean.

Thanks guys you are a big help.

 

Got Part No. LHE1620AA written on it?? That would be the Mass Air Flow Sensor. Don't take it apart!


Cheers,

 

Well I just finished reinstalling the throttle body. I wish I had put up with the stalling problem instead. But the TB was quite dirty and the EGR port was essentially completely blocked. Everything nice and clean and reinstalled. Now it idles at 1600 rpm. I'm even afraid to put it in gear at that rpm. I know this subject came up but I was already well into the job. My recommendation is DIYers don't clean the TB. Right now I have a car I can't drive and no idea as to what to do next. The nearest two Jag dealers are well over a hundred miles away where I wouldn't dare drive the car the way it is. Any suggestions will be appreciated.

EZDriver

 

I just knew that was going to happen, as I mentioned earlier, idles too high.
There is maybe something you can do to make it drivable in the short term, but you will still need that trip to the dealer. You will need a 2.5mm allen wrench to adjust the throttle butterfly stopscrew. Do this with the throttle body still on the engine, so it may require you to cut a little bit off the allen wrench so it will fit into the stopscrew. Turn the stopscrew counter-clockwise paying VERY CLOSE ATTENTION to how far you are moving it. Try to do it in 45 degree increments so it's easy to keep track of. Turn it 45 deg. twice then start the engine and see what the idle is. If necessary do it again. Once the car is drivable, [it will probably still be somewhat uneven] you can run the car until you can get to the dealer. Drive it to the dealer and before turning it over to them, turn the stopscrew BACK IN the number of turns you brought it out. Then have them do the throttle potentiometer adaption. At that point you should be good to go.

Personally, I would call them and ask to talk to one of their guys that is familiar with the older AJ16 cars. Make sure he is clear what your problem is, and knows what we are talking about, the throttle pot. adaption that is.

Good luck!

 

Thanks for the info. I will do as you suggest to get the car driveable. Just one more question. Where is the throttle potentiometer?

Thanks Guy

 

It's the device at the bottom of the throttle housing, as it sits when on the engine. Lead has a green, I think six wire connector.

Cheers,