Air distribution removal and cleaning

(JR) #1

Hi gang, just received the new gasket and I will be removing the air distribution block cleaning and removing and cleaning idle screw. Any concerns with removal and refitting the idle screw once cleaned? How would I set the screw back to factory settings? Your help would be greatly appreciated. Will be testing AAV and cleaning throttle body as well. I also bought brand new vaccume hoses off Ebay and will be replacing those. Your help is always greatly appreciated.

JR 85 Xj6 III

(motorcarman) #2

I think I remember the throttle idle bypass allen screw to be something like 7/64" or 5.5mm???

I would set it to where you want the idle (hot).


(Doug Dwyer) #3

When you remove the distribution block pay close attention to the orientation of the overrun valve (looks like a spring) so you’re sure to reinstall it correctly

As Bob says, set the screw to give an idle speed you’re happy with. Factory spec isn’t an altar we required to kneel before in every situation. With age and mileage it might not give the best results.

I’d say 800 RPM in “P” would be a good starting point. You can tweak it a bit higher or lower at your discretion.


(JR) #4

Doug, should that part be replaced for the neck of it?

(JR) #5

I will be removing idle screw completely, so my concern is when i screw it back in, how many turns or how far do I screw it down or back it out so the cat will start or at least idle somewhat?

(Doug Dwyer) #6

I wouldn’t.

Some suggest tightening the spring (you’ll see how) to compensate for age/wear/loss of tension. There’s no formula or spec that I’ve heard of…just by guess and by golly. Maybe one turn?

Perhaps best to just leave it alone.

Others will chime in


(Doug Dwyer) #7

I dunno.

Half way seems like a good place to begin

Or, count the number of turn it takes to remove the screw…then reinstall it with the same number. That’ll get you close


(Frank Andersen) #8

As Doug says; count the number of turns when unscrewing, JR…:slight_smile:

However, with the screw in place in whatever position - the engine will start and idle on the throttle gap and the AAV air ingress. Idle may be too high or too low - to be adjusted with the idle screw with the engine hot. There is no spec position for the idle screw - it is set to get your desired idle…

As a aside; reputedly there is a hardened seat at the bottom of the idle screw bore - to protect the aluminium body of the air distribution block against too enthusiastic seating of the screw. If so; check that it is not loose and blocking the air passage…?

xj6 85 Sov Europe (UK/NZ)