95 XJ6 suddenly idles extremely high. This occurs after having work done on the fuel system to recover from water getting into the fill-tube. The car sat unused for 2 weeks after that work - the this idling problem. Any insight will be appreciated.

RodQ7

 

With the throttle butterfly closed ( may be sticking open ) the Idle Air Control valve may be stuck or commanded to a full open position . Pull inspect and clean the connector on the IAC valve ( 4 wire ) connector to start with and verify that the butterfly is closed by twisting the throttle cable input shaft tower counter clockwise . Look for the shaft tower coiled return spring not broken . Other then broken , Recall # T493 also covers a weak throttle return spring on this tower . The wiring from the ECU to the IAC is independent and not spliced into other devices so it can't be corrupted with the exception of the common ECU connector corrosion . Any CEL codes ?

 

Thank you,

This gives more than a good starting point. I'm on it in the morning.

 

The poppet on the IAC can be cleaned with some carburetor cleaner and a brush but not by holding it upside down so the solution flows into and damaging the " UNIFILAR " stepper motor ( expensive ) . The intake manifold ( and devices ) gets gucked up and there is a air/oil separator to resolve this otherwise it is a recommended scheduled maintenance item to keep ahead of it . The IAC can be commanded full open as the butterfly is slammed shut and scheduled down to a lesser value over time so there is no engine stall as you pop off the throttle ( ? ) . I believe the valve body and stepper motor ( in some cases
) can be purchased separately to save money . The mounting screws
can be frozen so plan accordingly with some spray .

Another thread that may be helpful :

https://www.jaguarforums.com/forum/x...emoval-158796/

 

Alrighty now this might sound really stupid but I swear it happened to me. Call me an idiot but my 97 was revving waaay to high and would accelerate on its own (just like the new self driving s class) but what had happened was the throttle cable had gotten gummed up by the wipermotor and was thus sticking the throttle open, now chances are this isn't your issue but hey, it never hurts to start with the simple stuff.

 

Nope it is not stupid , the throttle cable does get gummed up and prevents the throttle cable from being retarded by the return spring . Your foot will not feel this . To repair it involves pulling off the cable so you can tilt it up and get some lubricate ( graphite ) in there just don't over overtighten the position adjustment nuts as they are sometimes brass . Airliners use teflon cables to overcome this between the engines RPM synchronization actuators . 3 grand would be too high to get the required air through the IAC seat area even at commanded full open position so I would look more at the idle butterfly postion .