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73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: dartresurector67 on February 07, 2022, 08:00:36 pm

Title: Rebuilding vacuum lines & emissions controls in a 1979 K10 350/5.7
Post by: dartresurector67 on February 07, 2022, 08:00:36 pm
Hi all,
A previous owner intended to register this truck as off-road only or in a non-smog county in CA, and none of the emissions or exhaust were in place when I bought it. I was living in OR at the time so I wasn’t worried, but now that I’m back in CA I’ve been trying to resurrect the rats nest of hoses and valves. Luckily it came from the factory without an air pump.
Rather than rebuild the quadrajet that was full of mud bee nests, and dealing with a string of lemon mechanical fuel pumps, I opted for the MSD Atomic EFI master kit, which also happens to be 50 state legal.
I’ve pretty much routed everything to where it needs to be, but I am getting tripped up on the 4 way thermal vacuum port on the thermostat housing. I know I have something wrong because the EFE valve is not closing during warmup. Trial and error just got me a permanently actuated EFE and Google hasn’t been helping either.

Can somebody walk me through how to read the diagram and what each port should go to? I’m having trouble orienting the real world switch to how it is portrayed in the routing diagram next to the radiator…
Also, does anyone know what the knob is supposed to be, coming out of the bottom right of the port as shown? One way check valve?

Thanks!!

(https://uploads.tapatalk-cdn.com/20220208/f8f5727da22299af0174cd6909b0dfa6.jpg)

(https://uploads.tapatalk-cdn.com/20220208/5543398df1be9fadaa92568695f5a656.jpg)


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Title: Re: Rebuilding vacuum lines & emissions controls in a 1979 K10 350/5.7
Post by: bd on February 11, 2022, 11:03:28 am
The "knob" is a metered delay valve.  What year/model is the truck?  Engine?  Transmission?  GVW?  I'm not satisfied that is the correct 4-port PVS/TVS.  Is there a part number stamped into one of the wrench flats of the valve?
Title: Re: Rebuilding vacuum lines & emissions controls in a 1979 K10 350/5.7
Post by: dartresurector67 on February 11, 2022, 01:52:18 pm
1979 K10 shortbed
350/5.7
Truck came with an automatic, was swapped for a Muncie SM465 by previous owner.
GVW 6200lbs
Not sure on part number, will check when I get home.
Title: Re: Rebuilding vacuum lines & emissions controls in a 1979 K10 350/5.7
Post by: dartresurector67 on February 11, 2022, 06:10:20 pm
No p/n on the switch, but the box it came in is from SMP STANDARD BRAND P/n PVS82