Renix high Idle mystery - Intake Manifold?

[Black_Black]

Since I've owned the jeep, it does a good rev on startup then settles down to 1000-1100rpm. In gear it will hold 700-800rpm.

I have been through dozens of IAC's over the years and the TPS is currently brand new and adjusted properly. Trying to figure this out I installed a fully extended IAC and did not plug it in. It starts up nice now no rev but within 5 seconds it climbs back up to 1100rpm idle with the computer still trying to close it even with it fully closed. Seems like there is extra air coming from somewhere. I don't think there are any vacuum leaks I've checked everything with a propane Torch.

I'd like to check the intake manifold bolts can I get in there without removing the fuel rail and everything?

 

[Black_Black]

Well the top and bottom rear bolts were loose, but that didn't change the idle.

It really sounds like there is a leak under the intake manifold, but I can't make anything happen with propane. The engine sounds odd to me in general it has a turbo like whine, but you'd think I would get a reaction from propane if there was a crack somewhere

I heard the block coolant temp sensor could cause high idle on these? There's no difference with it unplugged though and it does provide a good reading to the computer.

Also this cable is setup to slip about a CM before engaging is that normal?

I've been determined to figure this out about a dozen times now I definitely appreciate any tips!

 

[lawsoncl]

That other cable is the AW$ transmission cable, which looks like it needs adjusted. https://bleepinjeep.com/video/having-transmission-problems-check-the-tv-cable-first/

 

[Black_Black]

Awesome thank you!

Well I am running it with the TPS unplugged and fully closed. It starts normally now but everything else has gone back to where it was, 1100-1200 rpm idle. It seems like the ECU wants it there

Vac is 15-16Hg at idle? Wish I could find a leak. I'm going to replace the connectors for the TPS next

 

[Black_Black]

I meant to say I'm running it with the IAC unplugged not the TPS. Sorry for the double posts I can't edit

 

[RCP Phx]

Have you checked the TB itself?

 

[Black_Black]

It's perfectly clean, stop screw looks fine. I did find a small leak on the spring side of the butterfly shaft so I will look into replacing the shaft seals

I tried adjusting the TPS above and below 17% today, no difference. Still going to replace the connectors or maybe bypass them temporarily