Was researching the removal procedure of the idle air control valve, and according to all-data the steps look more involved than expected from just looking at it.
From looking at it I expected to just have to disconnect the plug and remove the 2 screws. Can anybody who has done it chime in on the process? Here is what I found in alldata....



Disconnect battery.
- - Remove the intake elbow to throttle housing hose.
Disconnect idle speed control valve multi-plug.
Disconnect throttle potentiometer multi-plug.
Remove clevis pin circlip.
Reposition link arm from quadrant.
Disconnect kick down cable (where fitted) from quadrant.
Open throttle fully and disconnect inner cable from quadrant.
Carefully release throttle against stop.
Fit pipe clamps to throttle body heater feed and return hose.
Disconnect feed hose from throttle body stub pipe.
Remove throttle body assembly from inlet manifold.
Remove idle speed control valve from throttle body.
Remove gasket.
Retrieve distance piece from throttle body recess.
Refit in the reverse order of the removal procedure.

 

One screw is hard to access with the TB in situ.

The threadlocking compound on the screws will sometimes cause you to snap the small fastener off in the TB.

I usually remove the Throttle Body and use a small torch or heat gun to melt the threadlocking compound as I turn the small screws.

I have a PILE of TBs with sheared IACV screws that were replaced because someone snapped the screws off in the holes.

You have been warned.

bob gauff

 

Gotcha, thanks for the quick reply. Sounds like something I should do at the shop rather than at my house. Don't have any torches at my house.

 

You don't need an Acetylene Torch, just a small 'pinpoint' flame or good Heat Gun to get the Thread Locker to soften. Those Butane 'micro-torches' will work.

I usually heat a little and put a socket on the screw. Give a little 'turning' pressure' and if it does not seem like it's going to release, I heat a little more.

Just don't 'horse-it' and snap it off on the first try. Work it like you want to re-use the Throttle assy.

bob

 

Thanks for the tip, could have possibly saved me a lot of trouble as I was planning to just remove it normally. But first I want to test it further. I rather just buy a new one and replace it than clean the current one.

I was sitting in my car in a parking lot talking with a friend when I noticed it idling pretty rough. I got out and unplugged it and it smoothed out pretty much instantly. I have had it stall out at idle and soon after start up a few times, but it hasn't happened in a long time, so I never worried about it. I want to spend some more time diagnosing when I get a chance before I buy the part.

 

I would re-think the 'BUY A NEW ONE'!!!!!!!!!

The last time I checked they were near a THOUSAND dollars US. (AND THAT IS WITHOUT the TPS or IACV.)

If you buy OEM you will get new IACV gasket and screws!!!!

bob

 

Lol I meant buy a new iacv not throttle body. Sorry for the confusion.

 

ThaT won't spare you from the hazard Bob's warning you about - you'll still need clean mounting holes in your throttle-body, bereft of tiny, brass broken screws to secure that new IACV....

 

I know, I will take his advice. Just was clearing up that I was planning on buying a new IACV and not a throttle body.

 

The IACV is not cheap either, is it?

 

Looks the same as the ones GM used for years. Is it wired the same? Chrysler used similar ones too, but I know they were wired differently from GM.

 

I think the GM IACV is the same as the Jaguar.
My 1988 Chev PU has the older style IACV and is the same as the 1988 Jaguar 3.6 XJ40.
That one threads in and has a SQUARE plug.

The later ones are the rectangular plug and should be the SAME for both GM and Jaguar.

bob

 

I see a Lucas IACV for $165. Not cheap, but nothing that'll break the bank.

The GM one is around $70 for the ACDelco part number #217-421. And I'm sure you can find it much cheaper in a different brand. Would be an interesting experiment.

 

Been there, done that! However, I was replacing the throttle body anyway because it was gummed up and repeated cleanings didn't fix it. Throttle wouldn't return to idle from small openings, so I replaced the body. I broke the small bolts transferring the IAC across to the new TB.

 

Can someone tell me where in the throttle body the iacv (stepper motor) is located. 1998 xj8 4.0 vdp. Thanks

 

The 1998 XJ8 is a different engine and forum section

Try posting here on the X308 section

XJ XJ8 / XJR ( X308 ) - Jaguar Forums - Jaguar Enthusiasts Forum

See page 57 of the Doc below