Hi All,

I've been working on getting the check engine light to go off on my 1995 XJS 2+2. I don't have the fault codes in front of me, but one of them was the EGR valve (replaced that), downstream catalytic codes for both banks, and a misfire code. I've cleaned the throttle body (with TPS removed) and the intake manifold (as best as possible without taking it off). Both were pretty filthy and the old EGR had lots of carbon on it. The check engine light is still on and has the same codes.

The big problems is when I push the throttle from idle, the rpms drop like it's going to stall, then a split second later the engine revs like it should. I've been away for a few weeks so I dropped it off at my local (non Jaguar) mechanic hoping he could get it sorted out while I was gone (can't pass an inspection in PA with a check engine light on). He believes it's the Throttle Position Sensor and that was at the top of my list that I gave him to check.

Anyone know of a good source for a TPS? He was quoted $400 for "brand x" at Carquest. I'm going to give SNG Barrett a call.

Thanks,
Ray

 

That does sounnd like the TPS to me. My car would cut out completely for a split second when mine went out.

Its part JLM12074

Some US sources sell the OEM part for a little over 400.00

but I like to get my parts directly from the Jaguar in Coventry , England

www.jaguarclassicparts.com

Choose 'OTHER COUNTRY' at the beginning so you they can ship the part here. Do not choose "U.S" as it will refer you to a dealer. Then enter the part number on the search box

They are selling the part for 134.00 Sterling British pounds which is about 219.00 dollars plus add 50.00 bucks (????) for shipping from the United Kingdom.

You should still be coming in under 300.00 dollars. The only down side is that shipping is obviously not as fast as if it was from the US

I ahve had plenty of experience with aftermarket electric parts on my AJ16 XJS. Not only can they be more expensive than the real thing, but they fail within a month.

Good luck

 

Since you have had the throttle body and TPS off the engine, before you do ANYTHING else, get it to someone with a Jaguar IDS or PDU diagnostic tool. ANY change, alteration or part replacement to the throttle body requires the Throttle Potentiometer Adaption be reset. During the reset you have to tell it you installed a new TPS. That is how the 'base setting' is set in the ECM; in other words, that's how the ECM learns what is actually zero percent throttle and TPS voltage. When you change anything or clean the throttle bore of coke buildup, this has to be reset to make the idle correct also.

Good luck!

 

Thanks for the information. After I posted my question, I checked out jaguarclassicparts too (it's one of the first places I always look and a great reference as well). I didn't want to wait, so I found a Jaguar OEM TPS from Motorcarsltd.com. It was $233 with shipping so that's about what I would have paid with shipping from England. I'll need to check to be sure my mechanic has the right PDU tool to reset the ECU. I know he said he spent about $15K on his computer system, so hopefully it has Jaguar in it. If not, I'll have to start searching for someone who does....ugh! Thanks for the assistance!

 

UPDATE:
I got the car back and the new TPS is installed. The check engine light is now extinguished and the car idles around 750-800 (sometimes higher when it's warm). I've put 150 miles on the car since I got it back. It's so nice that it runs smoothly again. I had new brakes installed and it pulls (hard) to the left. I've heard some thumping so I think it might be the front suspension mounts...another project!

 

RayJak,

Can you tell me if your shop had to hook up the TPS to a computer to reset it?

Thanks.

 

Vee,

They did not have the equipment. He did what I was going to do (just lack of time on my part) and that is measure the voltage of the old one (0.6v) and then fiddle with the new one until it measured the same. Then tighten it down and recheck. It seems to have worked.

Ray

 

Excellent, that is great information!

Thanks for remembering to come back and share!!