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Discussion Starter · #1 ·
I am starting to work on my 1999 DOHC that has a problem with the EVAPS system. I had to cap off the small vacuum line that comes from the vacuum distribution block on the firewall to the Vapor Purge Valve on the passengers firewall. It was causing a vacuum leak that caused a 171 and 174 error code. Capping that line brought my fuel trim numbers in spec and stopped the 171 and 174 codes. Now, of course I get an occasional 455(massive air leak code) because I have it disabled. I just got a new purge valve from Rock Auto and will try and install it this weekend. Does anybody know how to enable the EVAPS system without the FORD Factory tester so I can tell if the problem has been fixed? Sometimes because of the way the car is driven it could take a month before it tests it on its own.

Ed
 

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Some higher end consumer / small indy shop scan tools will allow you to force the EVAP test to run.
 

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Discussion Starter · #4 ·
Sheila,
The green test port is for connecting either the Ford EVAP tester or a smoke machine. Without the factory tester or a high end tester like Jeff said it is kind of useless to the home mechanic because some of the valves are open until commanded to close by the PCM. I am going to look at the wiring diagram and see how many wires are involved and see if I can make the valve close. I checked the Auto Hobby shop on the Navy base where I work and found out they have a smoke machine. They say nobody has used it in two years. I had to drop the fuel tank a year ago for a pump change and may have messed something up then. I have tried to bench test the purge valve which should be easy to do. It only has two wires and three vac. ports but never get the results I would expect. The small vacuum line seems to always be vented. I have checked several in the j/y and they all do the same thing but it is the easiest thing to try so I am starting there.

Ed
 
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