Hi,

Sunny day, I work on my Wagoneer

I am tracking vacuum leaks in order to solve my low idle.
The 4.0 runs well, but idles smoothly at about 200 rpm (according to the dashboard)

It wouldn’t be an issue IF the oil pressure wasn’t low and even lower at low hot idle .
So I would like to be at ____ rpm. Btw, what is a correct warm idle ?

Where should the 3 ports be connected to ?

- 1 air on the air box
- 1 vacuum under the coolant bottle
- 1 electrical under the coolant bottle.


Thanks

 

Vacuum under the coolant bottle goes to the heater control valve if you still have it. If you don't have it, plug the line. You don't need the troublesome valve anyway.

I'm providing a vacuum diagram or two for ya.

Put a wrench/socket on the intake manifold nuts and make sure they are snug.

 

Thanks Cruiser.

For the intake manifold, your comment is because it could help with the low idle ?

btw, idle is OK when I disconnect the line that goes to the fuel pressure regulator AND also the one that goes to the gromet on the valve cover (the one close to the firewall).

If I remove both, even better.

Any idea ?

 

begin with the intake manifold.

we have to make sure what things aren't on our quest to find what they are.

 

Intake seems ok. But I don’t have professional tools to do test.

 

what tools? 9/16" wrench.

 

I have these tools and did check
What I mean is I am not equipped to completely take off all the surroundings of the intake to do a « professional » check.

Is there a way to detect a leak in the intake manifold ?

 

Fog the area with propane (unlit). Engine should rev up if a leaky intake area sucks it up.

 

Propane ?

no risk ?

 

A lot of guys say starting fluid or brake cleaner. IMO propane is a little safer.

 

By the way, the canister was removed by the PO.
So nothing is connected to the airbox (see pictures at the beginning of the post).
Shall I leave it open ou put something in it ?

thanks