To All,

About seven years ago I replaced the TPS in my garage with a used unit purchased on eBay. It had been working fine all this time but now seems to be presenting the same conditions with idles all over the place…..sometimes bogs down

The TPS ON THE 96 model yr. Is a fixed position (No Adjustment). I remember installing and following a procedure involving turning engine on and off or key waiting a few seconds and repeating this three (3) times. After the third time computer was reset and worked fine.

It worked properly for 7 yrs. As I mentioned…NO COMPUTER!!

Does this ring a bell with anyone as I can’t find this procedure anywhere. The only thing close is the procedure for the IACV.

IS IT POSSIBLE THAT THIS WAS THE PROCEDURE I FOLLOWED AFTER INSTALLING THE TPS.

I think this was only for the 96 model year…. NO COMPUTER REQUIRED…………DON’T REALLY KNOW?



Thanks

Softball60/Paul

 

This procedure was certainly a test for the IACV.

While it is true that the TPS is made to be non-adjustable, if you are experiencing a high/low idle, you can modify the mounting holes so that the base idle could be adjusted, but I don't think that's your problem here.

Have you cleaned your throttle body. After 7 years of driving, it would certainly be gunked up again.

 

Vee,

As always thanks for your response.

YES …….YOU ARE CORRECT!

I completely tore apart the throttle body and cleaned. I also cleaned out the intake as it was full of wet soot ……….remnants of my prior issue with the O2 sensors?

I also installed the spare TPS I had in my parts bin. The TPS that I pulled off the throttle body was completely soaked and I believe was the cause of my current issue.
Completed the above tasks this morning.

Upon completion just went ahead and fired her up……….started right up and runs great……..I did not follow the IACV procedure.

1. upon start up it ran with usual choke like start ~11-1200rpm.
2. After a few moments idle came down to 750-800rpm
3. Let it idle to full warmup “N” on gauge
4. Took it for a spin ran great but noticed that rpm stayed at ~1500 rpm
5. Rapped on the pedal and rpm came down to normal
6. upon retUrning from the ride…..ran great!!!! but if I gradually raised the rpm , it would stay at a higher than idle…..again a quick rap on the pedal and it came down.
7. While standing over the engine and rapping the acceleration mechanism I could hear a clicking sound…..possibly the EGR…..but not sure……..don’t ever remember hearing that sound when standing over the engine while running and rapping on the accelerator .
ANY IDEA?

PLEASE NOTE THAT IT IS NOT RANDOM IDLE UP AND DOWN ON ITS’ OWN.

Before the cleaning this morning I was experiencing random idle movement, poor acceleration, engine cut off etc.

DID NOT EXPERIENCE ANY OF THAT AFTER I COMPLETED THE CLEANING, INSTALLING THE SPARE TPS ETC.

All in all I feel much more comfortable with driving her but will try solving this final minor “idle sticking”. Linkage seems free.

POSSIBLE ISSUE

1. Sticking component, EGR, IACV
2. Could injectors be involved in causing this issue
3. Something I am not seeing with the accelerator linkage


Your input is appreciated

Softball60Paul

 

I'm hoping it's not looking for a TPS reset....only done with a computer.

I wish we knew where the TPS % Open was before we replaced anything. I'd like to know what it is now. Can you read that with a OBD2 device?

You might want to put the previous one back on. But before you do, please read the % Open you have now. It'll be interesting to see if there's a difference between the two.

On a lark, run the car, get her hot, and, with the engine running, unplug the TPS. Count to 10 and plug her back in. Not sure if it'll do anything, but worth a shot. (don't burn your forearm)

 

Vee and All,

After messing around with the TPS and install on my original throttle body and having a condition that was not indicative of anything I have experienced on my 96 xjs. This condition was upon increase of rpm’s the accelerator would stick usually around 1500rpm’s. Once I would rap on the pedal the rpm would come back to normal 600rpm. ALMOST LIKE THE ACCELERATOR WAS STUCK…..MORE MECHANICAL THAN ELECTRONIC INVOLVING THE TPS, IACV, EGR, MAF ETC.

TRIED A NUMBER OF THINGS INCLUDING REMOVING THE THROTTLE PLATE ON THE THROTTLE BODY AND REPLACING WITH ANOTHER PLATE FROM A SPARE THROTTLE BODY THAT I HAD…THE THROTTLE BODY WAS COMPLETELY CLEANED AND LUBRICATED INCASE ANYTHING WAS STICKING.

Installed the cleaned unit w/newer throttle plate and it fired right up and did the same thing…..CAR WAS DRIVABLE BUT ANNOYING BECAUSE HAD TO RAP ON PEDAL TO BRING IT BACK TO 600rpms.

SO THIS DID NOT SOLVE MY ISSUE.

TODAY I removed the original THROTTLE BODY AND REPLACED WITH MY SPARE ….MFGD. IN 2005 vs original at 1995.

replaced the throttle plate back into the 2005 TB….HAD TO MODIFY THE ARM THAT ATTACHES TO THE CRUISE CONTROL BELLOWS.

WALLA………..IT RUNS NORMAL AGAIN…….IT RUNS AS GOOD AS IT EVER HAS!!!!!!!!

The only thing I can figure is the original throttle body had something ….possibly binding as you increased the rpm’s.


Took it out for a 25 mile trip to insure all was good….WASN’T GOOD……..WAS FANTASTIC!!!!!!

Thanks

Softball60/Paul

t

 

So you replaced the throttle body butterfly. Did you swap TPS as well, or did you keep what was on that throttle body?

I’m unclear about the 2005 butterfly. Do you mean that you took one off a 2005 engine? What exactly did you use?

 

Vee,

I had a spare throttle body that I purchased several years ago. The manufactured date on the TB was 2005.

My 96 xjs had a TB WITH A 1995 manufactured date.

the 2005 TB LOOKED LIKE IT WAS BRAND NEW……NO WEAR MARKS.

SO, MY FIRST ATTEMPT TO FIX THE STICKING RPM WAS TO PULL THE BUTTERFLY PLATE OUT OF THE 2005 unit and install it on my 1995 TB……THINKING IT WAS IN BETTER SHAPE AND POSSIBLY STOP THE STICKING RPM ISSUE THINKING IT MIGHT HAVE BEEN THE BUTTERFLY BINDING INSIDE.

The OLD TPS was removed on the original TB AND REPLACED WITH A SPARE UNIT I HAD IN MY PARTS BIN.

So, as I mentioned this attempt with adding the spare TPS and the addition of the newer butterfly did not cure the rpm issue.

This morning I removed the original Throttle body 1995. I put the butterfly back on the 2005 TB AND mounted THE SPARE TPS on the 2005 TB.

INSTALLED THE ENTIRE ASSM. 2005 TB w/spare TPS …PRESTO BINGO……NO MORE RPM ISSUE.

My ride was back as good as new.


AS I mentioned, something in the original throttle body must have been binding slightly so when I would rap on the pedal it would come back to normal idle.

Softball60/Paul

 

Strange, I don't think Jaguar produced this TB after 1996.

 

Keesh,

Is it possible that it was for another vehicle like XJ-6.

I did have to modify the throttle linkage slightly where it’s connected to the cruise control bellows.

Softball60/Paul

 

The Jaguar 2005 TB were controlled electronically, not by cable.

 

Keesh,

You are probably correct but see attached photos.

One with plastic bag is the original TB. DATE CODE SAYS 5195. I am guessing this mean 5 month 1 day 96 year part # 42704B

One mounted on vehicle says 2005 part # 42714B

they do have different part nos.

NOT SURE…..BUT IT BOLTED RIGHT UP AND SLIGHT MOD TO WHERE CABLE CONNECTS TO VACUUM ON CRUISE….NEEDED SLIGHT BIT MORE CLEARANCE FOR ARM THAT CONNECTS TO VACUUM.

Softball60/Paul

 

KEESH,

OLD AGE ….FORGOT TO ATTACH PHOTOS

 

Part number for TB XJS 4.0 AJ16 is: JLM12045 . For the 4.0 of the Jaguar X300 AJ16 is: NBC3061(BB). The same and interchangeable.

You may need to take a closer look at your mounted TB. You may have mistaken the nine for a zero maybe .

 

I've had this problem with the seemingly sticky gas pedal before. Even though you feel the stickiness through the pedal, you cannot when actuating the throttle body by hand.

I have resolved this issue, every single time, with a TPS reset using my PDU. I know most people don't have that access, but I would recommend, in the future, if you ever get yourself access to one, even through a repair shop, replace the throttle body with the "sticky" one and have it reset. You will then have two working throttle bodies.

While you're enjoying your perfectly functioning TPS, I would strongly suggest you record your voltage reading at idle, with the TPS you have there now. It may be valuable in the future, should you ever opt to reset the TPS manually in the future....or to troubleshoot an idle issue.

 

Paul,

I don't know if those codes mean build dates or not. Perhaps give Jaguar Classic Parts a ring and ask them?

However, if they do equate to build dates, 5195 won't mean 5th month 1st day 95. A four digit code will almost definitely mean week number then year number. So 5195 would be the 51st week of 1995. This is how 4 digit tyre date coding is set.

Cheers

Paul

 

ptjs1,

I do believe you are correct. Should have remembered this from years ago with dated coding on auto parts. Did you notice the response from Keesh. Not sure I understood what he was trying to tell me.

Thanks for response

Softball60/Paul

 

Paul,

Maybe Keesh was trying to suggest that your later unit was perhaps stamped 2095, not 2005?

Also maybe some people were thinking that you meant the later unit was from a 2005 car? (when Jaguar TBs had become electronic) Whereas what you meant was that it was an original AJ16 TB but just made in 2005.

Cheers

Paul

 

ptjs1,

Thanks for the response.

The TB that I installed definitely was marked 2005.

Don’t know if it was an original AJ16 throttle body……I would guess that it was…..but not sure.

Possibly built by Ford supplier for dealers repair stock.

Softball60/Paul