Hello the idle on my jaguar is acting wierd, it only occurs when I just started the car, it's worse when it's cold because then it will rev up then just die, but when warm it can make it without dying it is just swaying up and down until the setting itself perfect at about 700rpm. Like I said it only occurs when I just started the car, driving and so is no problem, only when first started.

Any ideas? What's controling the idle when the car starts?
Idle control valve is brand new and the idle is set up by the book, it's just at the start now.
Here is a video!



 

the only other thing that causes issues is a dirty or gummed up throttle body butterfly , this will cause idle issues ,

remove, clean really well, and set to ' 2-thou ' gap at rest, then go through the idle valve setup again ,

hopefully this might helps, and is good maintenance anyway

BB

 

I went back and looked at your other thread. I suggest cleaning the M.A.F sensor- both the screen and the connections and test the coolant sensor for the computer. Be careful not to touch the MAF screen, and use the special cleaner for it. Keep at it!

 

Easy to punch a hole or unseat it, that I can attest to!

Larry

 

its newly cleaned and set up, curious why it only happens I just started the car otherwise the idle is great

Guess I will have a look at the MAF then, haven really touched it more than removing it when dissembling the intake but worth a look I suppose. The coolant sensor I have tested and there is no problem with that

 

Don't know what did it but I cleaned the MAF, adjusted the throttle a tiiiny bit and tensioned the alternator and now it runs great again :-)

 

Happy dance. I knew you could do it.

 

good result,

BB

 

Thanks, but of course anything can't be good forever because it seems like the fault is still there, started the car today when cold and it behaves the same, didn't die so I guess it's a little better but it's right on the edge of dying, must have been that the engine got warm last time and now it seems to work fine when warm but not when cold I guess? ​​​​​​​

 

Maybe the connection at the MAF is iffy ...that plug can be a problem sometimes

Larry

 

Looks fine to me, haven't found a single contact that's badly corroded on this car, have cleaned the MAF contact as much as I could but no difference

 

Very sorry to hear, Simon!

You might check the VCM again just in case any code has been stored.

My gut makes me suspect its an electrical or electronic problem given that it went away for awhile.

However, thinking about cold idle management, when you replaced the Idle Air Control Valve solenoid did you clean the carbon and gunk out of the bore of the valve? If not, the gunk can prevent the solenoid pintle from sealing properly. There are also different pintle shapes. Did the one on your new solenoid match the old one perfectly?

Have you checked and cleaned the EGR port on the underside of the intake manifold, and if your car has a charcoal canister, the port for the purge valve hose?

Cheers,

Don

 

It's not that they are corroded, they're a loose fit .. and that can cause problems. Tighten the female jaws up.

Larry

 

No codes stored, I've cleaned the whole intake and all its parts so no junk anywhere and the valve is the correct one.

Have no egr or charcoal canister :-)

How does the air supply valve for the control valve work? The one that's next to the MAF and goes to the intake and the idle control valve, couldn't it be something up with that one or how does that work?

I also need to have the adjustment screw for the idle control valve almost maxed down to get the perfect idle, is it supposed to be like that? Cant remember it being screwed so far down before I cleaned and set everything up

 

Isn't loose at all, kind of hard to even get it loose just like all other connection so they all seem to be sitting pretty good

 

It's the grip on the pins inside the plug not the plug itself that causes issues.

Can't comment on the air bleed screw setting as it has very little if any effect on late models like mine .. although it can allow air to leak down through the threads so a few of us have used teflon tape to stop that happening.

Larry

 

Hmm have tried wiggle the contact but no difference but maybe it's just because this fault only occurs when the car is just started, sprays some start spray on top of the screw to see if it's any leak there but couldn't see any, and when doing the smoke test I could not see any leak at all anywhere

 

I learn something new every time I visit! I will be using this tip soon. Thanks Larry!

-Nick