C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Vacum Leak

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Old Apr 14, 2008 | 04:52 PM
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Default Vacum Leak

I replaced the heater core and now i havea vacum leak under the dash that i cant seem to find. Any suggestions on where it could be coming from?
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Old Apr 15, 2008 | 12:29 AM
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I am a bit confused, do you mean an engine vacuum leak?

What symptoms do you have?
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Old Apr 15, 2008 | 07:59 AM
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i thnk its a vacum leak, there is a sound coming form under my dash, and it sounds like suction. i have poor idle, at low rpms i can barely keep it running.
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Old Apr 15, 2008 | 08:12 AM
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Is the orange vacuum line that runs in front of core, in tact and connected ??
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Old Apr 15, 2008 | 08:47 AM
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Default Starter fluid

Here is little trick. Get a can of Starting Fluid and spray the area were you think the bad hos is. Leave the car running. When you hear the RPM's pick up when you spray the starter fluid, you located the problem.
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Old Apr 15, 2008 | 03:16 PM
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Yeah that was the first one i checked thinking the same thing i traced it as far as i can and it seems to be connected. As far as the starting fluid i think i know about where it is just not exactly and i don't want to spray down the inside of my car. I can here it just can't seem to find it.
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Old Apr 15, 2008 | 04:33 PM
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Here is a technique that I have used successfully to locate vacuum leaks in my 86'.

You will need:

- approximately 5 feet of tubing (preferably clear tubing)
- Duct tape
- Someone who smokes

1)Remove the MAF and snorkle from the throttle body

2)Slip one end of the tubing under the throttle plate

3)Tape up the throttle body with the duct tape as best you can, you want to make it air-tight if possible

4)Have a smoker exhale smoke into the tube

It will take a couple of minutes for the smoke to fill up the intake, but once it does, it will seep out of any leak point. Use a flashlight and have the smoker modulate their exhale speed to pinpoint the leak.

HTH
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Old Apr 15, 2008 | 05:31 PM
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I finally found the darn thing, i let the engine run for 20 min while i moved stuff around under the dash, just when i was about to give up i move a big bindle of wires and there was a little coupler that connects four vaccum lines together. thanks for all your help guys
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Old Apr 15, 2008 | 07:17 PM
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