89 Wrangler YJ with intake issues

Just Ben

Just Ben

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Joined
Feb 18, 2020
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Location
Fort Wayne
I've landed my first Jeep, it's an 89 Wrangler with the 2.5 that I suspect has intake issues and I'm trying to figure out a trouble shooting method.

The issue is that it sounds like it's sucking air and I figure the throttle body isn't opening enough.

I'm not sure if this is indicative of an idle air controller or a throttle position sensor.

Also are there benefits of just saying F it and installing a new throttle body assembly and if so what are recommended shops or parts?

This is my first post, I hope this is the right place.

Thank you
 
Can you locate the exact area it is sucking air? I've used a propane torch (not lit) with a length of hose on the end. Slightly cracked open so there is a slight flow of gas coming out and probing around all the areas that like to leak. If you suddenly get an increase in rpms as you move the hose around then you have located the leak. Now you know what/where the problem is.👍
 
Isn't the intake supposed to be sucking air? I'm confused.

Are you talking about an audible sound that sounds like it's sucking air even when it's just idling? If so, that to me sounds like a vacuum leak to be honest.
 
Chris said:
Isn't the intake supposed to be sucking air? I'm confused.

Are you talking about an audible sound that sounds like it's sucking air even when it's just idling? If so, that to me sounds like a vacuum leak to be honest.
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The throttle body doesn't appear to be opening enough and creating a large vacuum, creating the sucking sounds.
 
Just Ben said:
The throttle body doesn't appear to be opening enough and creating a large vacuum, creating the sucking sounds.
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Have you tried cleaning your throttle body? I know they can get very gunked up sometimes.
 
The IAC (idle air control valve) is what allows air into the engine during idle. It may appear that the main throttle valve is closed however air is bypassed through the IAC. Try cleaning the IAC and see what happens.
 
Just Ben said:
I used seafoam aerosol which I believe led to this.
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Now that's interesting. I'd actually remove the throttle body entirely and visually inspect / clean it. For all we know, it could be filled with gunk.
 
Just Ben said:
Do you have a recommended method for the cleaning the IAC?
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I am sure that there are many articles of how to clean the IAC but I can give a few pointers of how I have done it.

I would remove the complete throttle body from the intake and clean everything at one time. I believe there are two torx screws that hold the IAC into the throttle body. Basically you want to clean the carbon from the IAC plunger and also the "seat" within the throttle body that the plunger sits in. I would not use extreme pressure or twisting force on the IAC plunger as you can cause damage to the sensor, just be gentle with it. An old tooth brush, scotch brite and carburetor cleaner spray are useful for this task. Also make sure that the O-ring located on the IAC is in good shape before reassembling.
 
Put in an HEI disturber and a carb for a 1972 mopar slant 6. Fixed that problem. Put in a choke as well. Now it runs as it should.
 
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