Just finished traveling from Venice, fl up to Ohio then Michigan through Canada over to Syracuse, Ny then due to the impending hurricane and a wife right in the middle, back in Venice, I got back ASAP.


NOW to the car 1996 XJS 4L Conv.

The car ran flawless for the entire 4000 miles in less than 10 days. I had installed new injectors, new O2 sensors (just 2 Upstream) Did not do the down stream...Just forgot... Old age!!, new cam cover gasket w/spark plug seals.

Like I said "NO ISSUES" Got around 24mpg wo/air & 21 w/air

Then returned for Hurricane Irma!!!
Got back in time to board up the windows and head to the shelter. Thank God nothing too serious other than downed Front fences and some shingles missing.

Parked the car in the garage while we were at the shelter...3 days.
Yesterday I started it up for the first time since returning.

It started fine with the cold idle then to normal after initial warmup. Drove it around and noticed that the idle was up to 1200rpm.

Tried wrapping on the gas pedal as this is how I solved it a long time ago. I thought it worked once maybe a second time also.....but no!!

Drove it around but still at every stop sign or light it remained at 1200rpm.

ANY IDEAS??

As always your responses are appreciated

Softball60/Paul

 

Started to investigate high idle.

What I found:

1. Idle is now 1500
2. Seems that the throttle pedal is stuck

Sounds like a mechanical issue!!

Any common problems with the pedal being stuck?

Thanks as always

Softball60/Paul

1996 XJS 4.0L Conv.

 

Worn or missing rubber bushes on the end of the throttle body extension rod. This is right underneath where the rods attach at the outside.

Disconnect rhe cable from the capstan. Rotate capstan and it pops right out of its round hole. This takes that cable out of the equasion. Any difference now when you turn the capstan by hand?

If not then it's a linkage or TB issue. If it's better then you have a cable problem.

 

I noticed the other day when the high started that the pedal would stick a bit but would work if I gave it a quick wrap.

Now it is just stuck!!

Thanks for the insight. I will look at it tomorrow.


Softball60/Paul

1996 XJS 4.0L Convertible

 

Start by cleaning the throttle body. The inside where the butterfly that is. Use carb and choke cleaner and spray it on a towel or rag and clean the carbon off that way. Do not spray it inside the throttle body. The solvent can and will travel down the throttle shaft and into the throttle position sensor and ruin it. Get as much of that black gunk out of there as you can. The most stubborn carbon buildup needs the rag sprayed down and leave it in the throttle body for about 5 minutes then go back and keep applying pressure on the carbon with the rag until its clean.

 

I did a thorough cleaning and lubricating the shaft/butterfly flap in throttle body from cable down to throttle body.

I got the throttle body to unstick w/gas pedal....That works now.....but I still have the 1500rpm upon start-up.

What would be some of the most common issues????

Thanks

Softball60/Paul

 

Sorry I hadn't done any followup but my computer crapped out and had to order new power supply. Back in business today.



Pulled the Throttle body off the intake and thoroughly cleaned the entire unit.

Boy was it filthy!!!!!

I hopefully was careful and didn't get any cleaner into the electronics.

Seems to be mechanically working smoothly....No sticking!!

Is there a way to check if the idle valve mounted on top of the throttle body is any good.

I took it off and cleaned it thoroughly.

I don't want to put the Throttle body back together and mounted until I am confident the idle valve is electrically OK!!



As always thanks for your help.

Softball60/Paul