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I have a feeling that my throttle body vac hoses are incorrectly arranged.
I know white is set correctly, however I believe that green (to lower intake manifold) and red (to rats nest) may be flipped at the TB nipples.
I saw a picture of another user's engine bay on a Reddit post which made me look in to the order, and since I have been having performance, idle and other issues, I wondered if this could be why.
In my setup (image 1) I have vacuum both sides of hose green, nothing at hose red.
My brain reckons they should be switched between port 2 and 3 nipples at the TB... The yellow square highlights what the FSM would have me believe in terms of numbered, correct order (hose placement is still obviously in question).
The car has had a rebuild, and I have just done the break-in Ks, so it's headed to the builder/tuner for a dyno tune anyway, so I could wait to ask him, but can anyone please verify prior to that?
So, here's some information.
The top line (1) goes to your oil injectors. This provides a large portion of idle air by metering in pre-throttle air. Your oil injectors will pull vacuum and suck air through this. You should have no vacuum at the upper port.
The middle line (2) goes to your fuel injector air bleeds. This also provides a portion of idle air. You should only see vacuum at the lower intake manifold. There should be no vacuum on upper port.
The lower line (3) goes to your rat's nest. It should see vacuum at the upper port, but that may be conditional. From the pictures I have found of the NA spacer, this should lose vacuum once the primary throttle plate is open.
If I had an NA block, I could tell you for sure. Somebody else will have to confirm if they're switched for you.
So, here's some information.
The top line (1) goes to your oil injectors. This provides a large portion of idle air by metering in pre-throttle air. Your oil injectors will pull vacuum and suck air through this. You should have no vacuum at the upper port.
The middle line (2) goes to your fuel injector air bleeds. This also provides a portion of idle air. You should only see vacuum at the lower intake manifold. There should be no vacuum on upper port.
The lower line (3) goes to your rat's nest. It should see vacuum at the upper port, but that may be conditional. From the pictures I have found of the NA spacer, this should lose vacuum once the primary throttle plate is open.
If I had an NA block, I could tell you for sure. Somebody else will have to confirm if they're switched for you.
Wow! So they're definitely not hooked up right on my car, then!
Thank you very much for the detailed explanation. I really appreciated the thorough description of what each is responsible for.
I am going to switch the lines around and see how that performs.
