Crossfire Vacuum Line
Thread Starter
Instructor
Joined: Jan 2006
Posts: 173
Likes: 0
From: Cleveland Ohio
Crossfire Vacuum Line
I just picked up an 84 project that someone gave up one. It has a new motor installed but idles at about 1400 rpms. I found a vacuum line off in the rear of the intake on the drives side. It is not for the brake booster. Has a hose fitting and points twards the firewall. Where does this line go?
Thanks
Thanks
Last edited by clevette; Oct 20, 2007 at 03:58 PM.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
For starters, on a "project" you are really going to need a FSM (Factory Service Manual). There is a strange looking 90° fitting that screws into the far left, real of the intake manifold. The threads for the fitting are much larger than you would expect for the hose size, and the fitting is a strange shape. If that is what you are talking about, the fitting takes a short (1" to 1 1/2") length of hose that has a plastic, three port (tee) check valve, on the other end. The tee takes a hard plastic vacuum line that disappears through the firewall wrapped up with a wiring harness for the HVAC controls. The other heads to the left side of the car and has a tee that heads, one to the cruise control, and the other to the vacuum accumulator (ball).
I hope that is the right fitting and that this helps.
RACE ON!!!
I hope that is the right fitting and that this helps.
RACE ON!!!
Burning Brakes
Joined: Sep 2006
Posts: 1,202
Likes: 3
From: MD
Check the throttle shafts for slop. Any 84 with over 75k or so will develop slop in the Throttle-Body shafts and it will cause a ton of idle problems. Just a heads up. For a lot of good crossfire advice check out
http://crossfire.homeip.net
http://crossfire.homeip.net
Burning Brakes
Joined: Sep 2006
Posts: 1,202
Likes: 3
From: MD
Yeah, you gotta send/take them somewhere that can do it. The aluminum gets bored a bit bigger and bushings are installed. A steel throttle shaft can only ride in cast aluminum so long before the hole starts getting bigger.
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
The rule of thumb on CF TBs is they wear out around 50k, but I've seen them worn out at as low as 29k original miles. There is no rhyme or reason on a time frame for wear...its just a steel shaft press fit into a cast body that will wear considerably over time and causes a large vacuum leak on any crossfire motor which is a very common issue.
When the TB wears, it makes it impossible to balance the TBs and will cause idle issues and others. Even if you get the balance perfect, as soon as you move the throttle plates the wear in the shaft hole will come into play again and the setting will be off and leak again.
The only real fix/solution is to have them bored on the shaft hole to true the hole and have them bushed and then they will be good as new...better actually.
When the TB wears, it makes it impossible to balance the TBs and will cause idle issues and others. Even if you get the balance perfect, as soon as you move the throttle plates the wear in the shaft hole will come into play again and the setting will be off and leak again.
The only real fix/solution is to have them bored on the shaft hole to true the hole and have them bushed and then they will be good as new...better actually.
