87 C4, vacuum line to fuel tank???
08-11-2011, 03:10 PM
#1
Heel & Toe
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87 C4, vacuum line to fuel tank???
I took the vette in for our semi-annual smog check and it flunked the leak down test for the charcoal canister. I replace one vacuum line where it goes behind the radiator but flunked again.I found an old post that said there is another piece of vacuum hose in front of the drivers side wheel well. anyone with a pic of this one. There is a lot of stuff under there. Any other likely places to look for rotted rubber lines?? Thanks
08-11-2011, 04:19 PM
#2
The 87 is not complex once you know the layout. That is a purge line on the driver side that runs to the tank. It MUST be in good shape or the system leaks. Common problem with the metal tubing around rear wheel well.
In the nose the vac line runs to the brake booster area where it T's to a line thats toward the distributer.
The other small line os connected to the T-body where it splits and feeds the egr solenoid too. There is 3/8 tubing to the purge solenoid with one that is nothing more than a vent. Does not go anywhere. Just lays in the nose.
You should have a sticker on the shroud that details the vac lines in this area, not the purge lines.
In the nose the vac line runs to the brake booster area where it T's to a line thats toward the distributer.
The other small line os connected to the T-body where it splits and feeds the egr solenoid too. There is 3/8 tubing to the purge solenoid with one that is nothing more than a vent. Does not go anywhere. Just lays in the nose.
You should have a sticker on the shroud that details the vac lines in this area, not the purge lines.
08-11-2011, 07:41 PM
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Not sure what year they switched to two vacuum sources, check the diagram on rad and use this to help you diagnose (from my 86 FSM)
http://members.shaw.ca/corvette86/Ev...l%20System.pdf
86 Vacuum diagram
Later 2 vac source diagram
http://members.shaw.ca/corvette86/Ev...l%20System.pdf
86 Vacuum diagram
Later 2 vac source diagram
08-11-2011, 08:41 PM
#4
Race Director
Instead of replacing vacuum lines here and there, you need to get a mytivac vacuum tool. It will allow you to apply vacuum to the whole assembly and isolate where the leak is.
08-12-2011, 11:33 PM
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Same thing
I have a 87 as well with the same test failure. I finally broke down and started from the gas tank replacing all of the vacuum hoses up to the tank in the driver's side wheel well. There was only one short section of vacuum hose that had rotted out. It was located behing the wheel well in a very difficult area to see let alone work on. I would hook up a vacuum pump in the wheel well and test the complete system as i replaced each length of vacuum hose. As it turned out that little devil was the one causing me the leak problem.
Hope this is helpfull.
Gary
Hope this is helpfull.
Gary
08-14-2011, 10:58 AM
#6
Le Mans Master
There is another one on my car that was coated in undercoating. it is in front of the wheel well on the left hand side just where the floor flattens out from the curved portion of the wheel well.
It causes a gas smell as well. (1986 early)
It causes a gas smell as well. (1986 early)
