Well I failed emissions testing 2 times. The first time I took my truck I passed everything but the evaporative line test to the charcoal canister. They stick a line in my tank that pressurizes the tank and check for pressure at the charcoal canister. There was no pressure. That weekend I got under the truck and started looking around and trying to pressurize the tank. To make a long story short I found a "T" on the line that was covered with plastic to keep pressure from going thru and then I found the same thing on the the top of the front tank. I then pressurized the tank and there was flow to the canister. I then took the truck to get emissioned again. Now I failed the fuel cap pressure test. All the pressure escapes to the charcoal canister so there is no build up.

There is suppose to be a 1 way check valve on the tank so no fuel escapes if the truck is upside down. I just bought the truck so there was no mention of why the previous owners may have done this. Plus they live in a non emissions city so the didn't give a F.

Can someone confirm any of this and possibly help me find parts and or part numbers. I have all data but I've been looking everywhere for check valves and I find ****. TIA!

Update:

I've been doing alot of checking. No service writters seem to know what is right. I talked to one and they said the roll over valve is suppose to close when it gets to a certain amount of pressure but how is that suppose to happen? Pressure doesn't build that fast to close a valve. I checked my rollover valves and they're fine.

There are no leaks in my lines. I tested from my charcoal canister to the t fitting for both tanks. Pressure builds and comes back out the line because it can't go anywhere else.

So that brings me to what the second service writter said. He told me that the charcoal canister is suppose to hold the pressure. I blocked off all holes including the caps and it did hold but once I put the caps back on they didn't. So I bought a new canister and caps thinking this was the problem. I tested it and it did the same thing the old one did. The caps aren't solid so it doesn't close the hole off totally. I'm guessing incase to much pressure builds it can go somewhere. So other then that I'm stumped. I'm just thinking if I plug the holes in the charcoal canister I'll pass but I'd really like to know what I'm missing.

Do any of you have anything else between the t from the tank to the charcoal canister? Purge valve, anything? I don't and in all data it shows a purge valve but doesn't show the location. The purge solenoid is after the canister so its not the problem but regardless it stays in the closed position when off I've already checked.

So problem is after the t for the fuel tanks and before the canister. If possible can someone take a pic of their charcoal canister line. I'd like to see if theres a valve that I'm missing. Thanks everyone!


1995 F150 302 in Phoenix AZ.

 

This is a TSB for my 87' 302. Check TSB's for your year.
91ford21
RECALL NUMBER
90E92
Date
February, 1991
To: All Dealers
SUBJECT: Emissions Recall 90E92 - Cracked Fuel Vapor Hoses on Certain 1986
and 1987-Model F-Series and Bronco Trucks Equipped with California 5.0L Engines
AFFECTED VEHICLES 1986 and 1987-Model California F150/250 and Bronco trucks equipped with 5.0L engines having calibrations 6-54Q-R00 and 6-54S-R00 (1986-Model) 7-54R-R05/R11 and 7-54S-R05/R11 (1987-Model). The trucks were manufactured at the Kansas City, Michigan Truck, Ontario Truck, and Twin Cities Assembly Plants.
Fuel vapor hoses between the vapor valve on the fuel tank and the metal tube leading to the carbon canister may crack or split and cause the affected trucks to exceed evaporative emissions standards.
SERVICE ACTION Trucks returned for service will have vapor hoses replaced.

Notice also, they mention a "Vapor Valve"!

 

Thanks I've checked through all the TSBs and recalls. I've been through all of alldata and there are no specs or anything. I'm going to the dealer tomorrow and check a few more part #'s I found on all data. See if there is a purge valve. Ill test it out and see if it works for what I need it to do. This is just plain ridiculous.

 

I've read in more than one place, that the purpose of adding this test, was to grease the skids for retirement of older vehicles. Do you have the ratchet type gas caps, both w/ good seals? Last time I failed that part of the test, they pressurized the front tank, & my rear tank cap not only had a split in the rubber seal, but was replaced w/ the wrong type somewhere along the way.