Of Sasquatch, Loch Ness Monster, and straight forward vacuum diagrams

[Ressurection]

OK, I'm finding a bazillion images of vacuum routing and none seem to look anything like what I have.

'72 Blazer, 350, NO a/c, unmodified with rebuilt Q-Jet.

As you can see, there are 3 ports on the front:
1. behind fuel filter; 2, under fuel filter; 3. right hand corner

The components I see that need connection are (right side of carb):
1. Vac distributor advance; 2. choke; and 3. TCS solenoid.

Additionally, the PCV valve (my truck only has one, on left valve cover, right cover just has a breather); brake booster.

I do have the charcoal canister still on it.

****GOALS/QUESTIONS:
I need the proper routing diagram based on the following:

1. Is the TCS solenoid necessary/does it hinder or help performance? If it's not necessary, or hurts performance I'd like to remove it, so...vac routing would be how?
2. What do I need to do to remove the charcoal canister?

Thanks, and any help is appreciated!

 

[Greg72]

Do you own a copy of the factory assembly manual?

That's going to be your best chance for getting things 100% authentic.


-G

 

[Ressurection]

No. :/

 

[diesel4me]

The transmission controlled spark was a "crutch" GM added to improve emissions and it doesn't really help driveability or performance ,it hurts it if anything...

I deleted it on the few vehicles I had with it intact...

Here is a page off a Corvette forum that has some good explanations of what it was meant to do,and some diagrams,most GM's used the same setup in those years,so it should be the same as what your truck would have had originally.

http://www.73spot.com/index_stats_files/emission/tcs.htm

 

[ashman]

I'm getting the impression you aren't looking to get factory correct, just make the truck run properly, right?

I don't have a Q-jet so the locations of the vacuum ports may be different, but I'll try to help.

OK, I'm finding a bazillion images of vacuum routing and none seem to look anything like what I have.

'72 Blazer, 350, NO a/c, unmodified with rebuilt Q-Jet.

As you can see, there are 3 ports on the front:
1. behind fuel filter; 2, under fuel filter; 3. right hand corner

The components I see that need connection are (right side of carb):
1. Vac distributor advance; 2. choke; and 3. TCS solenoid.

Additionally, the PCV valve (my truck only has one, on left valve cover, right cover just has a breather); brake booster.

I do have the charcoal canister still on it.

****GOALS/QUESTIONS:
I need the proper routing diagram based on the following:

1. Is the TCS solenoid necessary/does it hinder or help performance? If it's not necessary, or hurts performance I'd like to remove it, so...vac routing would be how?
2. What do I need to do to remove the charcoal canister?

Thanks, and any help is appreciated!

The TCS was removed long ago on my truck and everything I've read says it just hinders performance. I think you're safe to remove it. Same with the charcoal canister. Just disconnect the vacuum lines from them and you should be fine.

From the pics, it looks like your choke is hooked up fine. Your PCV valve should go to the large vacuum line with the bolt in it in the center. Your brake booster will go to a similar one on the back. The smaller tube on the right will go to your distributor.

If you have any other vacuum ports on the carb just plug them and you should be good to go.

Hope that helps.

 

[JDNobodi]

Sorry dude the closest I got is a 73. Maybe it be of some help.

 

[bigblock72]

I don't have a good picture so hopefully I can describe it clearly.

The driver's side front port goes to the vacuum advance. You can ditch the TCS solenoid, it was purely to reduce NOx emissions in first and second gear and then allow vacuum advance in high gear only.

The large port in the front of base plate goes to the PCV valve. I don't know where the smaller hose goes that is connected to the end of the PCV hose in picture 1, probably shouldn't be there.

The port on the side of the carb that the vacuum advance is connected in picture 2 originally went to the air cleaner and can be capped if you are using a different air cleaner.

JDs picture is quite similar to how a 72 would have been plumbed just doesn't have the EGR valve like a 73 does.