need some help please

[bradepp]

1990 gt has been running like crap. Found the problem, its under the intake manifold a hole that seems to either need a plug or a new line that goes to something somewhere. its on the front of the intake underneth, when i plug it the car smooths out and idles great. I also get my brakes back. so my question is do i need to plug it or should a line go to something else.

 

[stykthyn]

Its a vacuum tree. Plug it.

 

[Rick 91GT]

Replace the line with a new piece of hose...

 

[bradepp]

thanks for the info. i know its a vacuum but does it suppose to go to something or just plugged. Thanks guys.

 

[bradepp]

What size hose to plug if it just needs plugged. Thanks a bunch in advance.

 

[stykthyn]

Is it a threaded hole? Is the fitting still in?

 

[bradepp]

No its not threaded. The threaded one is still in good shape, its to the left of the threaded one. Sticks out about an inch or so. Plugged it with a bolt and it runs like a mother. Just want to make sure its supposed to be plugged and if so what size or if its has a hose that's suppose to go some where. Car has never ran this good till i found this vacuum leak. I'm glad I found what's wrong for cheap just want to make sure that i get it right. Thanks for the help!!

 

[stykthyn]

Sounds like someone re-ran the lines already and the plug came out.

 

[bradepp]

Plugged it with a piece a hose and a large lag bolt, car is running great just wish I knew if that is good enough or do I need a true hose plug. Thanks for all the help.

 

[jsw81]

It might be the fuel evaporative purge hose. There is a return line that comes from the charcoal canister. Follow the line and see if it's connected or if one even exists. Also pictures are a plus when trying to troubleshoot on an internet forum.

 

[LarsD]

It might be the fuel evaporative purge hose. There is a return line that comes from the charcoal canister. Follow the line and see if it's connected or if one even exists. Also pictures are a plus when trying to troubleshoot on an internet forum.

I was going to post this.

I had the same problem you are OP, found that old purge valve hose was all cracked up and leaking. I just put a rubber plug on it, and the car started running great again.

 

[Green 94 5.0]

If you dont live in an area that does smog testing, you can do without it.

 

[bradepp]

No smog testing here in Oklahoma. I will leave it plugged and thanks for the help. Sorry no pictures couldn't get a good pic of it anyway since it's under the intake behind the distrubutor.

 

[jrichker]

Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Wiring & Engine Info Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif


Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel. The canister is normally mounted on the passenger side frame rail near the smog pump pulley.

It does not weigh but a pound or so and helps richen up the cruse mixture. It draws no HP & keeps the car from smelling like gasoline in a closed garage. So with all these good things and no bad ones, why not hook it up & use it?


The purge valve solenoid connector is a dangling wire that is near the ECT sensor and oil filler on the passenger side rocker cover. The actual solenoid valve is down next to the carbon canister. There is about 12"-16" of wire that runs parallel to the canister vent hose that comes off the bottom side of the upper intake manifold. That hose connects one port of the solenoid valve; the other port connects to the carbon canister.

Purge valve solenoid:

The carbon canister is normally mounted on the passenger side frame rail near the smog pump pulley.
Carbon Canister: