vacumm leak and cruise control.

[BigBurbBastard]

I have a 92 suburban with the 350 that has recently developed what I believe to be a vacuum leak. Around the same time, my cruise control stopped working and I believe it's correlated. I asked around at O'Riley's and the guy said it could be my cruise control module line, but I don't believe it has a vacuum line. I've also used the propane trick and so far have found nothing. It can be heard in drive, reverse, light throttle pressure or shutting off the motor. Please help.

 

[someotherguy]

Welcome to the forum, you'll want to post this over in the Engine section as more people will see it in the appropriate area.

You are correct though that your cruise has no vacuum connection. 1992 Suburban has all-electronic cruise. A 1991 and earlier Suburban, still being squarebody, would have a vacuum setup.

Suggest you re-post this in the Engine section and give more info on what the symptoms are, though I'm pretty sure you have two separate issues.

Richard

 

[someotherguy]

LOL...for those of you looking at me like I'm nuts, the post got moved from the "Feedback and help" forum at the bottom of the board. So now that it's in the appropriate spot -

Most common cause of cruise failure on the "old style" interior GMT400's (88-94 truck, 92-94 SUV) is the cruise stalk itself. The wiring gets broken, usually internally so you can't tell, where it bends going into the column. You can disconnect it under the dash and test it easily with a multimeter set on continuity. The plug is a blade style with an orange (usually) plastic nub on it and it should be clipped under the dash roughly in the area above your left knee. There's only 4 traces on it; once you discover which is the ground, you can test the other 3 against it as they'll be the button functions.

As far as the vacuum leak, please describe the symptoms - you're just hearing what sounds like a vacuum leak, or is it running/behaving differently (other than the likely unrelated cruise failure) ?

Have you checked the MAP sensor line at the bottom rear of the TBI unit? It's an easily overlooked potential vacuum leak as it's hidden; the boot on the plastic line gets hardened/brittle and can leak. Handle it gently as if it's not the issue, you can easily damage it just checking.

Richard

 

[Schurkey]

Cruise control stalk replacement

https://www.gmt400.com/threads/cruise-control-multifunction-turn-signal-stalk-lever.42220/

 

[TAF2003]

I know the video is titled for 96-99, but worth a shot:

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