TPI guys vacuum questions

[Mikkelsen]

Hello,

So i am trying to find someone who has installed a TPI in a pickup to figure out a few vac line spots. The 3rd gen diagrams are kinda helpful but i figured i would double check with someone here to see what has been done.

My truck is a 1974 so no emissions junk is on my TPI. I have a MAP setup and it is running well so no issues there.

I need to find a spot to run my HVAC line as i am keeing my AC and heater. how is yours done?

Where do most of you have your trans vac line ran to? I have mine on the pass side of the throttle body.

How do you have your canister purge lines ran? I have a strong gas smell in the garage and i tink the vac lines not being complete is causing it.

pics would be great.

Thanks,
Tim

 

[dyeager535]

HVAC on all the later vehicles AFAIK was run off a vacuum canister (usually a ball on the trucks and cars of the 80's) and a check valve. The ball and check valve is there to prevent the loss of vacuum under acceleration from making the blend doors move to their default positions. I *think* my plenum is a MAP one, there are two ports on the passenger rear side, one was what my EGR was hooked up to, the other is cruise. I'd like to try a ball and see if it would smooth out cruise at all.

Anyway, the canister purge was run off a solenoid, so running the proper canister would be necessary, and since solenoid control was used, don't believe there would be any special requirements for vacuum, just full plenum vacuum should be ok. The factory parts are out there, should not be hard to retrofit, I'd strongly suggest going that route. I will when I swap my stuff around, wish I had done that in the first place. There is no good way to vent the tank otherwise, you open it to atmosphere no matter how else you do it.

Trans line should also be full plenum vacuum, if the lines at the throttle body are "ported" that would probably have been canister purge and/or EGR, if full plenum vacuum, no difference than at the rear. But if using a trans with modulator, it needs to "know" what the vacuum is in the plenum to determine load on the engine.

 

[Mikkelsen]

That helps a lot thanks! I will do some part hunting.