Ok. so the 1996 XJS 4.0 started running at a low idle 450-500 rpm last week.

I could live with it but oil pressure is low at that idle speed also. I vowed to look at it on the weekend. Saturday morning I get in the car and now it is the 1500 - 1800 rpm issue........uggggg When I first bought this XJS that was the problem. In October of 2016 I took the XJS to Don's Jaguar in Flemmington NJ and George used a Autologix reader to fix the idle speed. $250.00. not bad to get it running right but not cheap either.

A couple of months ago I purchased an Auto Enginuity ScanTool OBD-ll compliant., Rev 7C. Price was right on the Auto Engunity E bay store. I did not get the Jaguar specific package. The XJS was running good so I had no reason to play with it.

Fast forward to today I'm considering buying the $230 Jaguar Pack from Auto Enginuity so that I can look at my idle air control valve and throttle position sensor.


My question is has anybody used Auto Enginuity with Jaguar service pack to adjust the throttle position sensor? As usual, all help is greatly appreciated

 

Looking forward to learning more about Auto Enginuity and whether it can resolve the idle issues on the AJ16... please keep us posted.

 

Apparently the Autologic machine can reset throttle adaptations! It must be set to an x300 car since
it does not have an XJS option.

i am now even more interested to find out if the AutoEnginuity machine can do it!

 

Has anyone ever come to any conclusion here about the AutoEnginuity?

 

From what I am hearing abot the AJ16 engines, there is a known idle issue and things like varying dile speeds, low idle, high idle can be the result. I bought a new 95 Vert last month and while it was freezing when and where I bought it (Baltimore and drove to CT), the coolant temp was low and the idle was high(1200) but could get it to 1000 and at time by blipping the throttle, down to around 700 or 800. I think the proper idle speed and normal eng temps is 675. Feeling the throttle plate on the TB, I could tell it was sticky especially at closed throttle and would physically stick closed if I put pressure closing the throttle. Hard to open the next try. This TB is prone to lots of carbon around the butterfly plate and a good cleaning using carb cleaner on a soaked rag around the inside bore and plate will help if not solve the varying idle. Also make sure the CTS sensor is good as that informs the ECU how much fuel to provide when cold/hot. Also TPS very finicky also.
For me, when it gets warmer, I will go over the TB completely .
That's a start for you anyway. I don't have any experience with the scanner tool you are referencing so can't comment on that.. Someone had replaced the Idle air valve some time before I bought the car. Probably to address the idle issue but the carbon around the plate may have been or is the issue all along.

 

The throttle body cleaning is certainly a must. I’ve done it and have since added an oil catch can and it keeps the throttle body clean, at least for the last two years I’ve seen no oil on the outside of the throttle body, nor is there any oily residue on the hose that ties into the intake elbow.

That being said, to do a cleaning correctly, you want to take the throttle body off the car so both sides can be cleaned. What you point out is very consistent with a gunked up butterfly. It will not take you long to pull it off, just make sure you have something to block the coolant line that plugs into (and out of) the throttle body. I find a golf tee is perfect to shove in there.

I’m still hoping someone someday can report back on the capability of the Autoenginuity.

Thanks.

 

You can remove and 'unwind' the spring 1/2 turn and then snip the long end down a little. Then you wind the spring the extra 1/2 turn and install the retainers.

The extra tension on the spring should help close the throttle so you won't need to 'blip' the throttle.

I did this dozens of times when I worked at the dealer.

bob