Well I had a dealer tell me I needed to replace a whole rear half shaft ($900)for an ABS fault code.
Got just the outer CV joint for $174 and repalced it myself. If it were my TB I would take a shot at
cleaning it myself. I don't think you aregoing to get the dealerto do it.

 

Be careful with the engine stalling. I had a difficult time diagnosing the problem and it turned out to be the fuel pump. After replacing the pump, my car has not stalled out again. when does your car stall? does it start right up again? how many miles? read my other post to see if it sounds like a similar issue?

 

jun4ever, I am not sure what you are attempting to accomplish by cleaning out the inside of the throttlebody when you have a fault with the position sensor. I will tell you that the inside of the throttlebody does have a protective coating on it and you can't use just anything to clean it. You can try using a rag with some water on it to clean the inside. If you have to go with something more harsh, use a rag with some isopropyl alcohol on it. DO NOT!!!!! use something like carb cleaner or other cleaner of the like. This WILL!!!!! strip the protective coating off. With that being said, my Ford Expedition had the same sort of setup and after talking with guys there, we have all cleaned the inside of the throttlebody with carb cleaner with no issues (once you do it, you will have to continue to clean it annually or so). Granted, I know the protective film on mine is gone as I have polished the inside of the throttlebody to help improve the air flow. But, that is a different discussion all together.

As for the position sensor, what I would tell you to do is to remove the sensor itself and take it over to an air compressor. Then, using aair cleaningtool, blow air into the sensor to blow out whatever you can. Odds are, you have a little bit of carbon build up in side the sensor and it is causing it to read erroneously. I had a similiar problem on my truck due to the port/polish job I did (managed to get some metal filings inside the position sensor. It did fix the problem for a little bit, but ended up replacing the sensor in the long run.

 

TPS= Throttle position sensor and TB= Throttle body
2 independent of each other, although they are one housing. The jaguar TPS is fly by wire, meaning there is no linkage from the gas pedal to the TB, the TPS reads the position of the gas pedal and determines weather you are crusing, part throttle and oe WOT. No cleaning, this is a sealed unit, so it either works or does not work, sometiimes you will get a flat spot, meaning your foot or you been crusing at 55 since you owned the vehicle, that sweet spot on the TPS can get worn out, there is no cleaning. Needs to be replaced.

The TB, is the portion that sucks in the air. That tends to get 'gummed up" if you haven't been changing your oil and or air filter, it can on rare occassion get a thick black ring of goop arounf the "throttle" or plate that seals the body. So when you're at a light for example, foot on the brake, the throttle plate is just about sealing the throttle body and only ketting the minimal amount of air for proper air fuel ration. When it gets gummed up, it may cause an erractic idel or stumble.

That portion can be cleaned. You can disconnect your air cleaner hose/tube from the throttle body and if it looks black and or gummed up, get it cleaned, but you can't use any old cleaner, they sell a special throttle body spray clearner for that.

If it looks, silverish/gold, i wouldn't mess with it.

On the jaguar the TPS and TB are all one unit, like i said, so if the TPS goes, you need the entire assembly. You can search e-bay or the web, there are a few folks out there that actually rebuild them for 1/2 the cost. If you're getting your part from the dealer, the price is expensive, and they don't rebuild, they replace.

If it was my car, i'd take a peek at the throttle body myself. If it's all clear, no cleaning required.

 

If your intake tube is lined with a gunky film..you might want to disconnect the electrical connector for the MAF and pull it out and spray some non residue electronic cleaner on the little thermistors too..this will raise hell with idling and stuff, if they are all gunked up..

 

Never owned a car with fly by wire set up but wouldn't what used to be a traditional TPS
be located at the gas pedel? I am guessing that there needs to be a motor of sorts in
the throttle body to get a siganl from the ECM to open the throttle plate??? So what
ever is located in the TB is not the sensor butthe actual item that is being controlled by
the ECM??? Agian, lots of guessing on my partjust trying to get a better understanding
of it.

 

OK LESSON FOR TODAY. let me turn off caps so white stype dont bitchhhh. now on fly by wire the PEDAL position sensor is on the gas pedal. 1 piece as an assembly, the TPS is on the throttle body, rivited sealed unit, and calibrated, so why someone out there may be ably to take it apart and repair, its a fly by wire system and the last thing you want to do is have the car take off on you like and AUDI. while you cant clean the throttle body, Jaguar doesnt recommend on the flyby wires as they do have a coating on the throttle shafts. If this is removed it allows dirt and oil etc to contaminate the TB and cause sticking and failure..Now on your stalling issue, I agree with Hank, many stalled and dying issues with X types are fuel pump related, and the issue you have with with limp home etc is from stalling. Its a result or symptom or result not a cause. It can also be the result of not TPS signal or difference between the TPS tracs since its redundant and if theres a difference in the reading it throws codes and doesnt know where its at,causing stumbling and dying, same symptoms as a fuel pump issue, so as a tech I would have to go with what the ecu says it saw and replace the throttle body as well. Otherwise you need to hook up a fuel pressure test gauge to monitor fuel pressure and drive around with it taped to the windshield until it stalls and see if the pressure went away first.But another thing about working with a dealer is this, I would save the part and try that, if it continues to do it then I would reinstall your old part and put the new one back on the shelf. sometimes you have to replace a part as part of diagnostics rather than go though a bunch of time consuming and expensive testing to come to the same conclusion. You cant readily do that at an independant without buying and keeping the part. Remeber you bought a Jaguar, and with it comes as any luxury car comes a more luxurious cost to maintain and repair. But then again, dont you feel good when valet pulls up your Jag rather than you Hyunda????

 

THE SUDDEN, accelleration is more tongue and cheek, as for monitoring fuel pressure, you do it like any othe injection system. On the earlier Xtype they have a shrader valve, the later that dont you have to use an adapter and unplug the quick disconnects and install between them, it has it own shrader. this is what we use for this and onboard injection system flushes. Since a cel is for the TPS and its part of the throttle body, its not available separatly. You can always try recycled parts and I have gotten from Ken....Xtypes are popular in recycle yards, and your talking 4 10mm bolts, 3 hose clamps and electrical connector to replace. No reprogramming needed, its 5 minutes in your driveway if youre slow....

 

Ah that makes sence that there would still need to be a TPS @ the TB as a feedback to the ECM! Guess we
could call the other one the PPSpedal position sensor! BTWis there a motor in the TB that moves the
Throttle plate??? Must be, huh?

 

yes theres a motor in the tb and the sensor on the gas pedal id reffered to as the pedal position sensor.....
I see you race the Grand National, I should post pics of my race car, 79 El Camino, and the 87 Suburban that pulls it.. I race em both

 

I just cleaned the throttle plate on my jag with seafoam spray and lube. The next morning I was leaving to work and noticed that it seemed as if the car was accelerating on it's own, by that I mean it feels as if im steping on the gas when Im not. If I bring the car to a complete stop and then let the break go the car rolls on it's own until it hits 1000 rpm it feels as if the car is accelerating on it's own. I also notice on the inst mpg It used to get up to 99mpg when I would let go of the gas when going down hill or had enough speed. when cleaning the plate I used my finger to push the plate back to clean behind it. Anybody experience this? Some thing is serously wrong here.

 

This is the exact same problem I am experiencing. Are there any Jag Mechanics that can help us understand what it going on here?

Thanks,
Andy

 

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