How do you purge the solenoid? Someone recommedned it once and I do not have a clue. Thanks.

 

The purge selenoid is basically a valve placed between the intake manifold and the charcoal canister. With my '94 after the engine warms up and at a certain rpm the computer sends voltage to the purge selenoid to open it which purges the charcoal cannister of fuel vapors. That is good for our enviornment. My selenoid valve was not closing at 169,000 miles which caused a constant vacuum leak. Replacing it improved drivability and mileage. Click on my name for details on how I found the problem.

 

[Click on my name for details on how I found the problem.[/QUOTE]

I went through your postings and did not see anything under purge solenoid. Can you give me a link? Thanks.

 

<HR style="COLOR: #666666" SIZE=1> The following is a copy of an earlier post of mine. This issue is a recurring problem evidently. Vacuum, Vacuum, Vacuum. Sorry about the length but this worked for me.

Mine did the same thing. First I took someone's suggestion and bought a tester for under $30 at A. Z. called a MihtyVac. I wish I had bought it years ago. It will pump a vacuum like using a caulking gun and has a guage. Start at a funny little thing between the A/C drier and the engine. It looks like a Tee with a little mushroom on it. Three hoses go to it. On my '94 Bronco 5.8 one little hose goes from that little check valve assy. into the vacuum reservoir that is moulded into the side of the evaporator box by the transmission dip stick. That hose had a hole in it so I cut out the bad spot and slipped the ends into a small hose to patch it. It takes several pumps to test the reservoir. Next test the little black hose from the check valve going into the firewall into all your A/C control *****. Pull a vacuum to 20 in. and see if it holds a minute. Then change a **** setting inside and repeat the test for ALL A/C and heat settings. That will test all the hoses and vacuum actuators (dash pots) to all the doors. Mine were fine. Finally I found that little check valve was not holding vacuum. The purpose is to hold the vacuum to the A/C actuators and reservoir up (say around 20 inches) even when your engine gets under load vacuum may drop to (say 5 inches or less of vacuum). If the check valve is not working it may let your panel air go to the default defroster and heater positions in the absence of good vacuum. That check valve assy holds the vacuum high for the controls. It only cost $11 at the Ford dealer. Now it will freeze me out no matter where or how I drive. You can also check your driving vaccuum with the tester. The little valve assy. tested fine until I simulated driving conditions. Here is how I found the problem...On my '94 Bronco there is a hose connector inside the cab mounted on the right of the heater core box. Pull it apart and connect the vacuum tester to the black hose going to the firewall which is the same hose I used tested under the hood. Go up a long hill and glance over at the vacuum guage on the floor. The vacuum should stay high if the little check valve is working . I guess you could also lock the brakes, put it in Drive and put a heavy load on the engine and instead of driving it to test for vacuum drop.

Then on the subject of fuel milage, that could be many things. My 5.8 runs much, much better after I used the MihtyVac to test the charcaol cannister selenoid valve to see if it is stuck open with wires disconnected. It was so I replaced it. It is next to the EGR valve and mouted with a cable tie. Wires go in the top, two vacuum lines out the bottom.

 

Hold on to your seat....I guess I was so focused on looking for a/c vacuum leaks that I completely missed a vacuum leak over by the pvc valve. One of the fittings was left uncovered, so I placed a rubber cap on it and waa-laa, nice acceleration and lots easier on the gas. Good fcking grief, I can't believe I missed that one.

 

Sht, even after finding and plugging two vacuum leaks, my a/c still fades. It happens when I am cruising in O/D and when I climb a hill, the a/c vents from the defrost ducts and floor.

 

I've seen the MighyVac at Harbor Freight but the Zone was less. Test, test and test.