Help With Teachers Comanchee

my teacher has an '86 comanchee, and he says it's making a sucking noise when driving. anyone know what it is? vacuum leak?

 

There is a vacuum canister with vacuum lines under the front bumper, passenger side.

 

Could be a vacuum leak but that would usually manifest as a high idle issue as well, if there was an issue with the vacuum canister or associated tubing that would typically manifest as the HVAC system defaulting to defrost when under wider (lower vacuum) throttle openings. If he could provide more information it would be helpful.

The IAC can make a loud sucking noise when it starts to malfunction and is a common failure part with the XJs and MJs.

On the upside it's a Renix Jeep. Troubleshooting them is typically pretty easy if you can run a multimeter.

 

what is that?

 

IAC Valve | Standard

 

replace it then?

 

Idle Air Control Valve. You can try and see if it gets rid of the sucking noise. I would avoid Standard if possible seems like I've seen those fail within 6 months or a year after replacement. And that's no guarantee that is his problem but if the only symptom he has is that sucking sound with no sky high idle or HVAC issues that would be what I'd be leaning towards.

What engine does he have in it? 1986 would have been either a Turbo Diesel (rare), 2.5L I4 (Renix Fuel Injected) and the 2.8L GM V6 (carbuerated).

 

Wow, that's kind of a vague description to make an accurate diagnosis Tyler, is this you? The "Mr. threw me off Perhaps maybe you should witness this phenomenon personally? Maybe his air cleaner came off and hearing the sucking sound of a carburetor~ but what do I know

 

This is a good point my comments/fixes mostly apply to Renix and "HO" engines like the 2.5 and 4.0.

 

Levi, i got the name changed. sma e jeep