vacuum and plenum leak... issues

rambob · May 16, 2012

I have the a/c switching to other vents while under heavy acceleration and climbing hills syndrome still. I replaced two check valves and pcv valve. didnt help. the a/c part doesnt bother me much.

but I am pretty sure it is related to poor performance I have been seeing lately on the interstate. which is when the a/c thing happens most. it like almost boggs down.

anyway, new thing lately I noticed, when I start is in the morning and let it run, it starts to make a loud sucking intake noise, gradually increasing in noise while gradually running worse.

there is little indication of oil in the TB. not pooling. dont use alot of oil. idk

any thoughts if the plenum IS my vacuum leak and contributing to the a/c switching thing?

how do I check for a vacuum leak myself. I can't pinpoint to sucking noise, but it is around the intake general area. mostly driver side.

SmokedRam · May 16, 2012

ONly thing I can tell you to do it take come carb cleaner and spray around the intake while it's running. When the carb cleaner finds the intake leak it will bog the rngine down.

As far as the plenum being blown, sometimes. it's just best to go ahead and get the Hughes kit and do it and be done with it. It's gonna fail, eventually. Had I kept my Gen2 any longer than I did, I too would have just done it.

Bigtman07 · May 16, 2012

Check also to make sure the valves are in the right order. I had the same issue and there was some sort of an order to them. The dealer fixed mine as a "courtesy" while my truck was in.

rambob · May 17, 2012

thanks

Mopar1973Man · May 17, 2012

Take all the plastic vacuum lines off and flex them in a bow curve and look and see if any start to split or break on you. Mine were cracking parallel to the tubing. So I ran down to the local hardware store picked up about 10 feet of vinyl tubing and re-ran all the vacuum lines with fresh tubing and no long have this issue.

As for your sucking sounds it because of the vacuum leak the IAC valve is changing or closing quit a bit because of the vacuum leak trying to hold a even mixture. After you redo the vacuum line that will go away.

rambob · May 17, 2012

thanks
awesome

what did you do about the tiny diameter tubing that goes into the fire wall. that is the brittle stuff.

Hotroder383 · May 18, 2012

Thanks man. I been havein this problem too with my AC. I have not changed the valves though. Might do that when I pick up the rubber line.

Mopar1973Man · May 18, 2012

rambob said:
thanks
awesome

what did you do about the tiny diameter tubing that goes into the fire wall. that is the brittle stuff.

Simple run what ever through and use a double barb fitting to fit both tubing. If you have to use a piece of rubber vacuum line on the plastic vacuum line in the cab to allow for a barb fitting.

rambob · May 18, 2012

ah gotcha.
thanks

whew. sounds like a full day.

vacuum and plenum leak... issues

rambob

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SmokedRam

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Bigtman07

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rambob

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Mopar1973Man

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rambob

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Hotroder383

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Mopar1973Man

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rambob

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