Traced to check valve and/or vacuum tank.
Where are they???????
Some info says remove refrigerant and evap cover.
Don't know if the valve or tank is inside the cover or not.
Is there a better way . Help , I don't have a freon recovery machine.
Any help would be greatly apreciated.
I hate to have to go to the "Stealership"
thanks

 

Vacuum resevoir and ck. valve are mount below the evaporator housing under the hood, the only access is to remove the housing assy. If you dont have means for removal you could opt to remote mount a resevoir and ck. valve.

 

Thanks
Thats what I did.Bought a ck. valve from the Ford "Stealership" and made a resevoir from 2 in pvc.Working fine.
Now my problem is coils. (6.8 v-10 w/112k)
Had a misfire code and I'm thinking I should change all the coils and plugs.
Any help with this would be greatly apreciated.
Thanks

 

My '92 E150 has a problem with vacumn as well. When I am cruising and the tehrain requires more power and the vacumn drops my a/c switches back to defrost...after I let up on the throttle and the vac builds up again I get discharge from the a/c vents...Is this the same on a '92 as this '97? Will I have to build a remote resorvoir and install a one-way valve? Thanks, Buford8

 

Where should I install the new check valve?

 

Your 92 should already have a vacuum reservoir. Just follow the vacuum lines from the intake manifold and one of them should lead you to it. They generally look like a large tomato juice can. If the vacuum diagram is still readable under the hood it will save you some time by showing where the line comes from and what else is connected to it including the reservoir.

 

Thanks for the repy Hanky...I already have found the reservoir and it's plastic...it doesn't leak...I want to know where I can put in another check valve that might fix my problem...I can't seem to find the original check valve. When the vacuum drops I can watch the vacuum motor go from a/c vents to defrost, then when vacuum increases it returns to the a/c vents...should I put the one-way valve near the vacuum motor?

 

Yes , you could do that. I would run a check of the diaphram/ motor and make sure it doesn't have a vacuum leak itself. If it has an internal leak , it may be more sensitive to vacuum fluctuations. Also, there may be a leak in the vacuum line that supplies the vacuum to the internal controls. If you can get hold of hand vacuum pump it makes checking the lines and controls a lot easier.