Ok in the process of acquiring a 99 xjr according to the info its got 45k on it and seems to start and run great. But the issue I am having it try and give it too much throttle and it chokes. I get the code P1797 and have cleaned contacts. If I barely touch the gas the thing lauches hard even spins the tires but give it too much throttle or try and go over 3.5k and it falls flat on its face. I can drive it all over the place an as long as Im driving it like a grandpa drives great drove it the 120 miles all the way home at 80 flawlessly seems to shift great as well. It downshifts fine but try and get the ultra power for which I want the car and it goes BLAH. Any ideas where to start looking??

 

Sure sounds like the throttle body and all the associated electrical components which would be capable of producing all the symptoms you describe. I think you said you cleaned the electrical connections. Did you check the vacuum hoses for cracks? Last thing is to replace with a rebuilt TB. Here or other places. Jaguar Electronic Throttle Bodies Application Guide - Jaytan Industries, Inc.

 

Yeah I am steering towards TB by the way it reacts it looks fine but I know tht dont mean anything. I have not taken the connection off I was talking about the pos and neg connections to battery is all. Wish there was a way too see if the throttle opened all the way when the peddle was depressed

 

Well took off the intake pipe and switched on the power and pressed the peddle and it opens all the way so dont know if the tb is at fault now hummm. Also disconnected the neg cable and checked all the connections at the ecu looks good but no change any ideas guys please

 

I was going to drive it to a jag expert but now instead of going BLAH with too much throttle an over 3.5k its doing it all the time and so I have it at the nearest shop I could go to and will go down in the morning to look at it and see what we can see any ideas are appreciated.

 

If you have not taken the throttle position sensor or throttle motor connections off, cleaned and reconnected that is what a $100 an hour technician is going to do. Removing and reconnecting will probably fix the problem.

 

Correct me if I am wrong but P1797 is listed under 5HP24 Transmission Control System for MY 1999 my link to it http://gusglikas.com/images/AutoRepa...tem%201999.pdf

 

Gus is right. P1797 is the transmission CAN bus fault code. And that could very well give symptoms like yours in that the engine and tranny ain't talking. Check the transmission module wiring connectors. A flea bay module goes for about $100. i

 

Ill start checking those things out as well. I got called by that shop they couldnt figure out anything cus they dont know jags funny thing is was acting like it did before drove great almost all the way back to my house, which was bout 20 miles. Then about 2 blocks from my hours the thing literally just died on me wouldnt restart so gunna have it towed to my place so i can start looking over trans wires and such and go from there. Any other ideas???? I am about to check and see if it will restart now and drive the last 2 blocks now that it has cooled down.

 

OK tried to go restart the car and now it wont even restart weird and only codes are the p1000 and p1797 very weird here. Any thoughts starting to make me think its fuel pump but who knows lol

 

why not check the fuel pressure?

 

Yeah gunna have to check that for sure

 

Cylinder washing?

 

I have no clue if that would be the case lol

 

Ok found out that not only had the internal hoses burst but pump 1 was bad so i just said screw it an chnaged both pumps, strainers, an hoses an now it starts and runs great except for the original P1797 problem. so back to square one

 

Thanks for the follow up post!

 

Kudos to you!

 

An for those that dont like going through the hassle of removing the 2 main hoses in back and draining the tank heres a tip. If you undo the clamp holding the 2 main hoses under the car it allows just enough room to pull the tank out enough to change everything with tank in car. Total time from start to finish was 1 hour and 42 mins and that includes jacking up the car, removing clamp holding vent tube and clamp holding main lines, removing battery, carpet and liners, and then undo electrical harness moving out of the way, removing the tank old downs and sliding it forward, removing top, removing pumps an lines, cleaning up tank with a wet vac and cleaning out tank of debris, install new pumps, strainers, lines, and reinstall.

Also I was wondering if anyone has got rid of the injection hose and gone the way of flexible plastic hose so as to not rot. Since I can get the tank out so easy I may do this at a later date. I dont think injection hose inmersed in gas is gunna last years and years not the best idea. Thoughts?? Is that the way it comes from the factory....... injection hose???

 

did you try to clear the P1797 after your fuel pump change? That second pump (for you R owners) sounds like it wasn't able to assist pump #1 that took pump #2's duties when you needed the extra fuel. Its supposed to only be a startup/idle fuel deilvery unit, IIRC, and forced to do all fuel responsibility with failure of #2. The P1797 may be a symptom/result of that fuel pump failure in the first place.

 

Yes I did and of course that wasnt my prob but I did find the problem I was reading another guys post and was reading that he had the restricted performance as well becus of codes in the climate control and so as per Gus's wonderful post about reading and clearing codes in the climate system which I had a few and upon erasing them my car runs great and codes are gone. No more P1797 and car runs like a raped ape