Just found an old receipt from 2017.
which states idle issues.
and states down the bottom “test idle circuit, test iac motor reset base idle & road test”

well i guess they did not fix it.
or if they did it did not last.
been same ever since i have had the car.

 

Devices that can reset your TPS:

1. PDU (only one on this list that can reset LTFT!)
2. WDS or Genrad 3500
3. Mongoose or J2534 clone
4. VCM (not sure about the VCM2)

I believe that is the list. The 600 posts may mention another device, but I think those are them.

 

Devices that can reset your TPS:

1. PDU (only one on this list that can reset LTFT!)
2. WDS aka Genrad GDS3500
3. Mongoose or J2534 clone
4. VCM (not sure about the VCM2) or clone

I believe that is the list. The 600 posts may mention another device, but I think those are them.

I would bet a lot of money that replacing the TPS with a new one will not resolve your problem. (They are fully sealed, so they cannot be cleaned, the ones used on the AJ6 engines can, and should be cleaned, but not the ones for the AJ16)

 

Don’t wanna jynx anything…..
but i found a bloke…
taking the car out to him on Thursday morning…
he knows the procedure…
so hopefully it is a 10 min in and out with my kitty purring like she should

 

So,
i found someone to do the reset finally.
shout out to Peter @ Just Jags.
great guy, some beautiful Jags at his shop.
Plugged it in, there was actually a few different error codes that came up……
One of which was IACV open circuit.
Cleared all codes,
performed the throttle adaptation,
started her up,
purring nicely……
exactly where she should be….

checked again for error codes.
nothing.
so hopefully any of the errors that were there were old and all good.

There was one error that helps me know something to fix, drivers seat front potentiometer.
so fingers crossed i can just replace the one.

but great to have her purring.
will certainly remember Peter and use him whenever i need someone and highly recommend.
some of the cars at his shop were just fantastic.
a beautiful V12 XJS caught my eye.

 

Glad you don't have a spot of stumble under your bonnet.

IACV open circuit was probably running the engine with the IACV connector removed during your tinkering

 

Hi Anbram,


Quickly browsed through all the replies so sorry if I repeat as previous members already mentioned.

Dont know if you got it fixed yet but i went through the same thing recently .., cleaning TB, replacing IACV, adjusting TPS, new Octopus Hose & Water Rail Hose (******* Hose) etc.

I also had the high idle (oscillating) although only around the 850 rpms combined with a occasional start and stall.

The start and stall was due to a faulty IACV that I replaced and problem fixed.

Unfortunately didn't correct my high and sometimes hanging idle (especially when at operating temp.) Ive done the TPS adaptation (have the correct diagnostics) but didn't fix it though. Not saying that the TPS adaptation might not also be part of your problem?

I also put an extra turn on the Throttle Return Spring but when all was back together my idle was still a little high and hanging when warm. I could also by hand close the throttle and my idle would go down to around 680 rpms so I just looked around for a stronger / new Linear Spring (see RED ARROW). Mine just needed some extra support to firmly close the butterfly against the Throttle Stop Screw. Easy and relatively cheap fix.

Idle in Park around 680 rpms and Drive around 580 rpms. No more hanging / oscillating and high rpms.

 

You covered everything very well

 

Thanks for the pic which was of great help. In my case it was not the issue.

 

Thanks. Pic was of great help. In my case not the issue. Went to a dealership still owing an original programming unit and they fixed it.

 

Further to the recent interesting debate provoked by "Spud Mat" and his high idle problem, I have since located some notes on "Throttle adaption" and "02 Sensor orientation"
I believe that when our cars were newer ( up to say 10 yrs ) the local Jaguar dealer would have performed these simple operations on many occasions in response to customer engine tune problems and complaints.
Unfortunately these days dealers only have equipment to deal with the new models thus it is a struggle to maintain our older models and keep them on the road and running to the parameters they where originally designed to maintain.
The details and comments in the attached notes I believe give an excellent brief overview on the workings of the ECU and both these operations.

John Herbert
1996 XJR

 

 

if anyone finds a WDS or PDU for sale i strongly suggest you grab it.....
i would love to get my hands on one and see everything i can do and tell me about my cat.

 

not sure what system the guy had that did the reset for me.
he had some kind of touchscreen tablet.

 

does anyone know anything about these?
https://www.ebay.com/itm/223569021373
supposedly it is IDS and they have the v131 software which works on jags 1995>
so should work on the X300.
get a laptop install a virtual machine software and set up windows xp and then install v131 IDS.
sounds good in theory.

 

It's called a Mongoose. In this case, it's a chinese clone. Will probably work for a little while, but eventually crap out.

Really the PDU doesn't do all that much more for the 96 XJS, but it does:
1. Reset TPS
2. Reset LTFT (which is just a math equation, so it should have no effect on how the car runs, just resets the averages in case you were seeing if a fix solved a trim issue)
3. Reorient oxygen sensors. (If you replace sensors one at a time, you should never need this)
4. Reset the kickdown switch on the throttle.

It should also allow you to add new key FOBs.

The Mongoose (cloned or not) will do all of the above, with the exception of #2 and maybe the FOB.

If you read that long post I linked in Post #77 here, you will learn all you want to know about these different units and their capabilities.