Does anybody know where the idle adj is on 85 xj6 4.2 eng? I've read and even seen a picture of where it should be, but those locations are not on my engine. Would appreciate any help!

 

So, to clarify, you do not have the air distribution block....a square-ish aluminum casting a few inches forward of the throttle body?

If not, I'm at a loss.

Maybe show us a pic of where you've been looking.

Cheers
DD

 

OK, there's a plate forward of the linkage spring that has an adjustment screw with a lock nut on, is that it? I thought that was for adjusting the gap on the butterfly valve. I wanted to increase the idle hopefully to solve my situation. To begin with the car wouldn't start and after some testing I discovered the spark amplifier module was bad, so I replaced it. The car started after that but when I put it in drive, it would die. It idles around 900 rpm. If I hold the gas pedal to about 1300 rpm, it would not die when put in gear but would die when I let off the gas. I have replaced the fuel pressure regulator and the plugs and have cleaned the throttle body and air flow sensor so far. I haven't adj the butterfly valve yet due to I don't have a .002 feeler guage. But it ran fine before all this.

 

Here's a pic of what I have.

Is this the adj screw?

 

no that is not it.

the part that Doug is referring to is at the center of the intake bolted to it. It has a large 5/8" hose clamped to it. The part is silver.

you will need a 7/32" hex wrench, bent in a specific angle to be able to get to the air adjusting screw. although some have achieved turning the screw with a normal hex wrench, it is not easy to turn it because the screw is usually stuck with crud deposits.

 

tool needed to adjust

 

tool needed to adjust

I am trying to upload images but no luck uploading from my phone.

 

Jose If you could get a pic to me it sure would help. I'm 73 and obviously blind as a bat cuz I just don't see what I'm supposed to be looking at ha Thanks Jose

 

https://www.jaguarforums.com/forum/x...cation-221085/

 

Hi again Jose, I just discovered an old post from David that shows the location and now I see it. Thanks Jose

 

You're welcome. I will upload a picture of the needed tool tomorrow morning.

 

Hi Jose, could you send me a pic of that idle adj tool that you mentioned? I have spent hours and bent an allen wrench every way possible to adj this idle. To increase idle, is the adj screw turned clockwise or counter clockwise? I can increase the gap at the butterfly valve to 1400 rpm and I can shift into gear and it will stay running at about 900 rpm. The idle screw doesn't seem to have any effect. Any ideas? Thanks Jose

 

if I remember correctly, clockwise is less air, counterclockwise is more air.

 

 

Thanks S.Bunzel for the pic, I've already discovered the location. By chance, do you know why my jag dies when I put it in gear. I adjusted the idle to specs. didn't help. If I push on the gas and get it up to 1300-1400 rpm then shift into gear it will continue running as long as I hold the petal down but die when I let off. I'm at a loss. Thanks again.

 

A couple quick checks

Make sure the duct between the air flow meter and the throttle body is tight and in good condition. If leaky/torn/loose the engine will really misbehave

Make sure the throttle gap is set to .002" and the throttle body is clean as a whistle.

There are other possibilities but I would begin by checking these two items first

Cheers
DD

 

Thanks for the reply Doug. I did as you instructed earlier today after buying a .002 feeler gauge. The boot between the air flow meter is a little frayed on the outside but the rubber inside seems in good shape, connections are tight. Starting after adj, high idle was about 1300 rpm and as it warmed up it dropped to about 950 but would still die when put in gear. ( out of curiosity Doug where are you in the pacific northwest? I'm in twin falls, idaho). Awaiting your reply.