Fuse 13 Mistery solved

July 06, 2014, 09:47:48 AM

Some time back i posted that a customers car was towed in with 10 service codes logged in the ECM. So i concluded that was impossible and looked for a blown fuse. Sure enough the NOTORIOUS fuse number 13 was blown. I changed it and all was well in the world. Not knowing why it blew always bothered me and i found out why last week. The car came in for an emission test with the SES light on. This means an instant failure and i explained to the owner i would have to fix it before testing it. I never test a car with an SES light on i want my emission record absolutely clean and so far it paid off. The state guys are always busting balls because of our outstanding record of passed vehicles. Just me by now you know i am NUTS. But here is what i found. The EXPLORER had 1 code purge solenoid circuit defect. Now i have changed numerous purge valves in fords over the years but not so much on the EXPLORER. So i raised the vehicle and removed the spare tire to see the valve and canister. Sure enough the bracket that held the carbon canister was rusted away and what do you know the wire to the valve was busted but still hanging on by the insulation. Gave it a slight tug and it separated. So spliced it soldered it and shrunk wrapped it and presto the code was gone. Then it hit me the wire has several cuts in it where the sharp edge wore through the insulation. So went to the computer and brought up the prints for the valve. WELL WELL what do you know FUSE 13 FED the valve. So what happened the wire rubbed through and grounded and blew fuse 13. But only once in all that time till it corroded the wire and set the code. So i cleared the code strapped the big ford on the dyne for a DRIVE CYCLE to get it ready for state emission testing. Guess what!!! It failed EVAP. Small leak. WHAT THE F$%^. So got out the smoke machine hooked it up and what do you know??? The filler neck RIM WAS ROTTED OUT. The hole was there right under the rim where the gas cap goes. That is why the code popped up and lit the SES light. Off to the parts store and ordered a new filler neck. It came in i installed it ran a drive cycle and all the monitors set and passed state emissions. The big FORD was once again smog legal and i found out why fuse 13 blew some time back. Believe it or not that blown fuse in that truck was stuck in my mind from day one why and how it blew and after replacing it it never blew again. like i said just when you think you have seen everything in this business, You get educated once again by a trouble that is WEIRD AT BEST. Have a great Sunday guys.