Vacuum lines!
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
IS there a metal plug on the lower TB under the larger pipe?IF so its possibly/likely the 86 TB.Take the top TPI cover off your TB and see what year is stamped in the circle.It will show ya something.
ALso,are you installing all the emissions from the diagram as well?
If not,you can plug off any TB holes you dont need with rubber caps.
Btw your diagram looks like an 88 or up set up on the Vette.Not sure about the F cars set up tho.
ALso,are you installing all the emissions from the diagram as well?
If not,you can plug off any TB holes you dont need with rubber caps.
Btw your diagram looks like an 88 or up set up on the Vette.Not sure about the F cars set up tho.
Thread Starter
Advanced
Joined: Jan 2007
Posts: 85
Likes: 0
From: Mesa Arizona
Well... I thought until a few days ago this was a complete '88 vette setup but apparently it is not. I found out i have a memcal out of a 5.0 '88 firebird and now I apparently have a '91 throttle body. any direction with that? will the 91 function properly with the 88 setup?
Also the top cover plate on the throttle body is a TPIS plate. not sure if this means it was purchased from them or someone just wanted a neat billet cover...
Also the top cover plate on the throttle body is a TPIS plate. not sure if this means it was purchased from them or someone just wanted a neat billet cover...
Burning Brakes
Joined: Apr 2004
Posts: 762
Likes: 2
From: Huntington ma
For what it's worth... on the '85 vette that canister purge line connects Underneath the TB on a small nipple pointed Down, sort of off-center towards the drivers side of the car. There is only One (large) port on the pass. side of the TB and it connects to the valve cover as a "breather".
There is actually a plastic Tee connected there at the port under the TB, the Other side of the Tee is a hard line that supplies vacuum to the EGR control solenoid/valve/switch (I think I remember that right - it's early...)
There is actually a plastic Tee connected there at the port under the TB, the Other side of the Tee is a hard line that supplies vacuum to the EGR control solenoid/valve/switch (I think I remember that right - it's early...)
Instructor
Joined: Sep 2006
Posts: 220
Likes: 0
From: Castleton NY
Are you running a canister on that truck? If not plug it. It is hard to tell from the picture...does it open into the plenum? Or is it just a casting hole that is not drilled out at the plenum? Maybe there is no nipple because it isn't used like it is on the Vette?
Thread Starter
Advanced
Joined: Jan 2007
Posts: 85
Likes: 0
From: Mesa Arizona
I was going to try to use the 84 gmc canister but I dont think that will work with all the extra connections for carb stuff. I am going to just get the canister for a camaro or firebird with only 2 ports on it.
No the hole is not drilled through on the side of the Throttle body. Thats what I think is so strange. Even the vacuum diagrams for 5.7L f-bodies showed 2 lines on the pass. side of the TB. Ill check 91 diagrams again and see wjat i get seeing as it is a 91 throttle body!
No the hole is not drilled through on the side of the Throttle body. Thats what I think is so strange. Even the vacuum diagrams for 5.7L f-bodies showed 2 lines on the pass. side of the TB. Ill check 91 diagrams again and see wjat i get seeing as it is a 91 throttle body!
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Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
I seen the pictures you posted and indeed its a 91 TB...the 91 compared to the 85-87 or so has a different cable linkage/hookup for the auto TV transmission and the gas.
The 91 uses different cables than the older cars,so be sure you get the correct cables if you are going to keep the 91 TB.
Someone installed that TPIS vanity cover on top...the GM ones dont say TPIS on there.
Alot of TPI parts can fit together,and you can end up having a 91 TB,88 runners,and 85 plenum and intake...see what I mean?
What TPI you use should be fine,just get the correct Trans cable,if its an automatic,and correct gas cable for that year to modify to your vehicle,depending in the TB used.
The 91 uses different cables than the older cars,so be sure you get the correct cables if you are going to keep the 91 TB.
Someone installed that TPIS vanity cover on top...the GM ones dont say TPIS on there.
Alot of TPI parts can fit together,and you can end up having a 91 TB,88 runners,and 85 plenum and intake...see what I mean?
What TPI you use should be fine,just get the correct Trans cable,if its an automatic,and correct gas cable for that year to modify to your vehicle,depending in the TB used.
Instructor
Joined: Sep 2006
Posts: 220
Likes: 0
From: Castleton NY
If the hole isn't drilled through, leave it. Screw the canister. It is only used to burn off fumes/vapors from your tank. With a custom project like yours...less is sometimes more. I wouldn't worry about making that hole functional. Leave it as is and drive on! You don't need it.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
If the hole isn't drilled through, leave it. Screw the canister. It is only used to burn off fumes/vapors from your tank. With a custom project like yours...less is sometimes more. I wouldn't worry about making that hole functional. Leave it as is and drive on! You don't need it.
Eventhough GM designed these vettes with a vapor canister, it is not really needed. I remove the whole setup on my 86 and capped the port on the TB. My 86 has a port where yours does not, that supplys vacuum to the vapor canister. That top port in the pic, goes to the CCV on the passenger side valve cover. The vacuum line pic in the first post is for the 87-91 as the 85-86 is different.
