Another issue has raised it's head. When the car is started from cold the revs are higher than normal(too high) and take a while to settle down, once it has settled it can be started and all is well. Any thoughts on this latest issue are much appreciated. Many thanks again. Anthony. Happy new year to you all.

 

How high?

For how long?

 

I would say 2000+, i switch it off if it won't settle when i think it's been revving too long(seconds rather than minutes).

 

Could be that the throttle cable is too tight? Has anyone serviced you're recently? Other thing could just be the TPS perhaps?

 

I have just had a look at the cable and it looks ok, where is the throttle position sensor located?.

 

On the side of the cast aluminium throttle itself. It's on the outside and looks like this 21884d1343646445-tps-replacement-p7300002.jpg (553×600) (jaguarforums.com)

 

Thanks for the reply, it looks like it is adjustable.

 

Has the car always been doing this, or is it a new phenomenon ?

ie, new problem that came with the cold weather ?


Z

 

Engine temp sensor in top hose

 

It has only done it since the cold weather.

 

Exactly the computer thinks the engine is well cold so it keeps the revs up ...new eng temp sensor LNA 1600AA NOT LRA1600BA-R

 

This is a fault then, it should not rev that high on a cold start. Having only had the car since the summer i have no previous experience on how it behaves in the winter. Thanks for all your help.

 

My XK8 starts with an idle speed of about 1.400 rpm, no matter if the ambient temperature is 0 or 30 degrees C. It takes about a minute for the revs to slowly drop to 700 -800 rpm. I usually wait with the gear lever putting into Drive until the revs have reduced a little.

Curious to know whether your jags also behave like this? I do not know the high cold start speed of other vehicles so.

Fritz

 

My understanding is that it's to warm up the catalytic converters. Probably also keeps oil pressure higher in the engine when cold? Low revving at a cold start can in some engine lead to not enough oil pressure so not everything is being lubricated sufficiently. I do not know if that is the case in our cars.

 

I never look at mine to be honest ..I just drive off ..But to be sure the temp sender in the top hose has a big contribution to make the the fueling so a good new one is an advantage particularly to the fuel consumption

 

Only reason why I let the revs drop before moving off is because the car makes a lot of power at 1500rpm or so which can catch you out if you don't expect it. I always have to tell people to let the revs drop first and keep you're foot on the brake. A few times people have almost rammed into another car because they thought it would just creep forward like it tends to do at normal idle.

 

I let mine drop below 1K RPM before taking off too. It doesn't take long, and I feel it may be less of a shock to the tranny, as well as getting the oil circulating. I don't believe it ever goes above 1400 RPM when started from cold.

 

Have a look at this thread and make of it what you will.

https://www.jaguarforums.com/forum/x...d-cold-214016/

Have you checked what throttle percentage is shown without your foot on the gas using Torque etc? Maybe you can adjust it down.

 

Looking at the thread has(i think) solved the problem, which is related to me having to disconnect the battery every night due to the problem i have with the micro switch on the drivers window. When the window issue is resolved and i no longer need to remove the battery hopefully things will return to normal. Many thanks.

 

I don’t know the particular problem you’re having with the micro-switch, but this might help;

is your car parked where you can just leave the window down when parked nighttime ? That way you can leave the battery hooked up and avoid the learning procedure with the attendant high rpm upon starting every day.

Z