Hi Gents, need some info on why my P38 4.0L (Thor) tends to over run when foot is off the throttle.
For example I can take my foot off accelerator at let's say15mph the old girl just stays there instead of slowing down, same as when foot off going downhill, she doesn't hold the speed.
Pain in th a*** when trying to gauge the slow down for traffic lights and crossings
Tickover is OK on both fuels (LPF and petrol)
Plenum and butterfly valve are clean
Is it a duff TPS ?
If it is the TPS will the electronics self adapt, or is some form of electronic reset required ?
Also, what is the correct setting for the two cables on plenum ?
Cheers

I'd say the cruise control wants adjusting, there needs to be some slack on the cable when the throttle is closed. The proper procedure is in rave, but you'd probably be able to find details on here as well as I've seen it posted before.

Hopefully this works

If its sitting at idle okay - about 750rpm, is your accelerator pedal a bit stiff? The way the cable is run from factory has a couple of tight bends in it that aren't ideal, and can make the aged cable bind, so it doesn't fully close reliably when you lift off. Unclip it and let it go where it wants and see if that makes a difference.

TPS will self adapt, it's one of the adaptive settings that can be reset. It saves the lowest voltage that it sees as throttle closed so anything over that will raise the revs but it will also raise them at idle so unlikely it is that. What sort of revs are you showing when slowing with a closed throttle? Mine will sit at around 1,000 rpm on the overrun and only drop when the brakes are used to slow the car.

Thanks for the replies, P38, altered gaps as detailed fro post 99MY, seems to be lot better.
Not got the cruise to work, have checked tubing for cracks - all OK.
No light on s/wheel when cruise is pressed - maybe duff relay or fuse - dunno yet..............where is the relay ?

On the cruise, pull off the pipe that goes to the brake pedal and try blowing down it. You shouldn't be able to but it's fairly certain you will be able to. It splits where it goes through the bulkhead. There are no lights on the steering wheel, or on the dash from memory (mine doesn't have cruise), only the light on the switch to show you have switched the pump on (but that won't light up if the bulb has blown).

Thanks, have already tried a Louis Armstrong down the pipe, nothing happened except wax being ejected from my ears !
All piping around T piece is OK.
Don't need the cruise, but nice to know it's available.

Have you pressed the button on the top left of the dashboard to switch the system on?

The steering wheel buttons don't do anything until that's pressed.

The one that is helpfully labelled as a motorway sign :crazy:

I think Hugh mentioned incorrect idle speed when he brought it in for conversion?

I slackened the cruise cable which was tight. Even so, not sure if the throttle body spring is closing the throttle fully.

Just got back on the forum - my email settings went nuts.
Anyhow, as per your post - It's a good idea to turn on the "motorway switch"
Cruise control now functioning 100 %....................Doh !

Some people think the switch sets sat nav up to direct them to Stonehenge ;-)

How's idle speed now Hugh?