86 intake rebuild large vacuum leak !
#1
Race Car
Thread Starter
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Did the rebuild, started, high idle whistle sound and runs like crap. I removed the Maf, center tube and Tb and checked the rubber connections and hoses to idle sol all ok. Put it back together same thing. This must be a large leak and seems to be coming from the center of the intake. I have the Center tube, Maf and side intake off poking around again every thing looks tight. I tried some Carb cleaner to ID the leak around all the hoses while running to Tb. intake ect as much as I could ' no go. My question is now what How can I check for a large leak like that ,should I remove the FR again and start over?
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#2
Burning Brakes
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You could try and use a hose held to your ear and pointed at various vacuum connections to try and isolate it from the sound. Is it possible that your one of your intake sections is not sealed to the head and you are leaking there? There are number of "holes" in the intake system with either hoses or sensors pluged into them to seal them and it could be just about anyone of them.
#4
Race Car
Thread Starter
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Maf are seated fine!
I took the front intake runners off I put the gasket in dry should I use a little gasket maker. I can't find a loose hose ect on this. I did not remove or replace the TB to lower intake or what ever you call it ,I may do that.
I have 2 parts I did not install that my be wrong for my 86. I kept all the old ones and these are not in that pile.
Rubber 928 106 163 00
Hose 928 110 673 00
I took the front intake runners off I put the gasket in dry should I use a little gasket maker. I can't find a loose hose ect on this. I did not remove or replace the TB to lower intake or what ever you call it ,I may do that.
I have 2 parts I did not install that my be wrong for my 86. I kept all the old ones and these are not in that pile.
Rubber 928 106 163 00
Hose 928 110 673 00
#6
Rennlist Member
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Easiest way to find a leak is with a smoke machine - hooks to a vacuum line, blows smoke into the intake. Escaping smoke visually shows the leak.
You can also pressurize the intake with low-pressure air and listen for escaping air.
You can also pressurize the intake with low-pressure air and listen for escaping air.
#7
Race Car
Thread Starter
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Will cigar smoke work
I really think its my intake gasket after powder coating and bead blaster the surface my be uneven. I'm going our for some Honda-bond thaks for the options!
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#8
Man of many SIGs
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Mark,
If the sealing surface of your intake was powder coated that will cause a problem. You will need to remove the poder coat from that surface.
If you need an extra set of hands, eyes, and ears let me know.
If the sealing surface of your intake was powder coated that will cause a problem. You will need to remove the poder coat from that surface.
If you need an extra set of hands, eyes, and ears let me know.
#9
Rennlist Member
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Originally Posted by WallyP
Easiest way to find a leak is with a smoke machine - hooks to a vacuum line, blows smoke into the intake. Escaping smoke visually shows the leak.
You can also pressurize the intake with low-pressure air and listen for escaping air.
You can also pressurize the intake with low-pressure air and listen for escaping air.
#10
Race Car
Thread Starter
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My flange fitting is not Powder coated but I went out and got some Honda-bond this I hope will work. I have this taken off and on down to a fine science.
I'll let you know it's a lot easier to eat up a paper gasket than find a smoke machine
.
I'll let you know it's a lot easier to eat up a paper gasket than find a smoke machine
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#13
Race Car
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Mine is a 3 wire WSM says to put 12v to center pin and then reverse I tried that Sol does not move. I can blow through the tubes. Is there another way to test this it worked before I changed the hoses and cleaned the moving part with carb cleaner.
#14
Captain Obvious
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Originally Posted by Tampa 928s
Mine is a 3 wire WSM says to put 12v to center pin and then reverse I tried that Sol does not move. I can blow through the tubes. Is there another way to test this it worked before I changed the hoses and cleaned the moving part with carb cleaner.
#15
Captain Obvious
Super User
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Originally Posted by Imo000
That's how I tested mine last year. Remove it and see if you can free it up on the bench. Maybe needs a really good cleaning. I used my batterr charger's 50amp setting to test it. It sure made it move quick.
Just to clarify this. When they say to reverse, they mean to switch between the two outside poles. So the middle, as you said was the +12, stay put and you move the negative between the two outside pins. This will reverse the motor and turn the vale on and off. Does this make any sense to you?