enigne surge

[blove78634]

I have a 92 Jimmy 4x4 SLT with a 4.3l. When I put the AC on and the truck come to operating temperature the engine will surge to approx 1100 rpm and down to the point of almost stalling. Where can I start troubleshooting at or is this normal?

I read on another forum that suggested a vacuum leak. Where is the line that would control this.

Other than this problem, it runs smooth.

Thanks for any advice in advance!!!!!

 

[Molson02536]

I have a 92 Jimmy 4x4 SLT with a 4.3l. When I put the AC on and the truck come to operating temperature the engine will surge to approx 1100 rpm and down to the point of almost stalling. Where can I start troubleshooting at or is this normal?

I read on another forum that suggested a vacuum leak. Where is the line that would control this.

Other than this problem, it runs smooth.

Thanks for any advice in advance!!!!!

Surging is caused by the AC clutch coming on and off when your running the AC. Clean your throttle body with a can of throttle body cleaner and make sure you spray your IAC to clean out you all if not most of the carbon.

Would not hurt to also give your engine a http://www.seafoamsales.com/ treatment. Good luck and keep us posted and this should help your surge issue.

keep us posted.
Molson02536

 

[blove78634]

I cleaned the throttle body and IAC. It is still surging up and down. The seafoam did wonders on it though. She drives alot better after running the seafoam through it.

 

[blove78634]

Surging follow up

This is just a follow up to my surging problem. I bought this truck used from a guy in Florida, and finding out that a lot of what he said is crap. I needed to change the valve seals due to a smoke cloud coming out at start up. This is a petty thing that just irritated me. So I figured that I would do a whole headgasket job and get the valve seals and head gasket in a complete kit. I took the top end off and took it to the automotive craft shop on Ft Stewart and cleaned everything thoroughly in the solvent tank. There was so much carbon build up in the plenum and heads that it was sickening. I replaced the IAC valve as well. When I put her back together she fired right up and haven't had a smoke cloud or surging problem since. I can run the ac at idle for 30 minutes and not a single sputter.

One thing I did notice was that the exhaust valves didn't have the umbrella seals installed, but a set came in the kit. I put those on and don't know if that helped either. When I took the EGR valve off, I compared it to the new seal/old seal and they were completely different. Meaning the one that was installed was a solid seal with no holes for the egr to do it's thing. I put the one from the kit on (had two holes in it), and that seems to have helped as well.

My recommendation for anyone doing this project is to get new exhaust manifold bolts and manifold flange bolts. I was surprised when I went to adjust the valves that the 1992 Jimmy that I have doesn't require valve adjustment. Torque the rocker down to 20lbs and your good to go.