78 Vacuum Switch on Water Neck Question-PLEASE Help
Thread Starter
Instructor
Joined: Jan 2001
Posts: 206
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From: Columbia, SC, USA
78 Vacuum Switch on Water Neck Question-PLEASE Help
Hey guys,
MY 78 SA L-82 originally had a green vacuum switch that screws into the water neck, which has 3 connection points, where 3 vacuum hoses connect to it. Two were from the smog pump, and one from a separate mechanism. One of the connections broke, and I ordered a new one from GM. The NOS replacement (AC DELCO) only has 2 connections on it. I looked in the assembly manual, and it shows only two lines going to the switch as well. WHAT GIVES???
I connected the extra line (one of the smog pump lines, the one without the check valve) to a vacant connection point on my carburator, but now the damn thing runs a little hotter?
Anyone know what's going on?
Thanks, and sorry about the technical question. Taylor
MY 78 SA L-82 originally had a green vacuum switch that screws into the water neck, which has 3 connection points, where 3 vacuum hoses connect to it. Two were from the smog pump, and one from a separate mechanism. One of the connections broke, and I ordered a new one from GM. The NOS replacement (AC DELCO) only has 2 connections on it. I looked in the assembly manual, and it shows only two lines going to the switch as well. WHAT GIVES???
I connected the extra line (one of the smog pump lines, the one without the check valve) to a vacant connection point on my carburator, but now the damn thing runs a little hotter?
Anyone know what's going on?
Thanks, and sorry about the technical question. Taylor
Platinum Supporting Dealership
Joined: Dec 1999
Posts: 6,425
Likes: 1
From: Traveling the US
Re: 78 Vacuum Switch on Water Neck Question-PLEASE Help (Vader953)
Mine broke too. The replacement I got was also 2 connections. I decided a zero connection was better and pulled off all my emission crap. Oops, did I say that?
Thread Starter
Instructor
Joined: Jan 2001
Posts: 206
Likes: 0
From: Columbia, SC, USA
Re: 78 Vacuum Switch on Water Neck Question-PLEASE Help (Chris@VetteFinders)
Chris,
Great idea, but my car is so stock, I'd hate to change it now. Does anyone else have any input? Someone has got to know!
Great idea, but my car is so stock, I'd hate to change it now. Does anyone else have any input? Someone has got to know!
Melting Slicks
Joined: Oct 2000
Posts: 2,144
Likes: 195
From: Englewood FL
Re: 78 Vacuum Switch on Water Neck Question-PLEASE Help (Vader953)
Last year I purchased replacement switches from Napa. I gave the counter
person the original GM part no.s and they crossed them over to Napa
part no.'s. They looked like the GM switches with the same number
of outlets.
person the original GM part no.s and they crossed them over to Napa
part no.'s. They looked like the GM switches with the same number
of outlets.
Platinum Supporting Dealership
Joined: Dec 1999
Posts: 6,425
Likes: 1
From: Traveling the US
Re: 78 Vacuum Switch on Water Neck Question-PLEASE Help (Vader953)
Chris,
Great idea, but my car is so stock, I'd hate to change it now. Does anyone else have any input? Someone has got to know!
Great idea, but my car is so stock, I'd hate to change it now. Does anyone else have any input? Someone has got to know!
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Re: 78 Vacuum Switch on Water Neck Question-PLEASE Help (Vader953)
It is a two-port system. One vacuum line runs to the early fuel evaporative (EFE) actuator valve system controlling the heat riser control valve and the other runs to the air diverter valve on the air injection reactor (AIR) system on the smog pump.
[Modified by paul79, 9:58 PM 7/2/2002]
[Modified by paul79, 9:58 PM 7/2/2002]
