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CHECK ENGINE light puzzler

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  • CHECK ENGINE light puzzler

    While we are waiting for the answer to Frank Ford's puzzler on Car Talk, here's one for your consideration. This happened to me, when I picked up my Forester from the body shop at closing time on Friday.

    I was pleased with the work, which involved removing dents from the front door and rear panel on the right side of the car. As I drove off there was the acetone smell of fresh paint, so I rolled down the window to clear that out. Driving further, all of a sudden the CHECK ENGINE light on the dash board lit up. This was the first time in 109,000 miles that I'd seen it. "Can some sensor actually smell paint?" I wondered.

    I had to pick up a friend from a visit to the hospital, so I didn't have time to investigate this further at the time. The car ran fine, and soon the smell of fumes was gone. A few hours later, back home, I read the Subaru owner's manual. This stated that one possible cause for the warning light was a loose fuel filler cap. "Aha," I thought, "that must be it." I went down to the garage to check it. I pulled up on the fuel door release (on the driver's side floor), and walked around to the right side of the car. The fuel door had not popped open. I gently pried around the edges of the door, to no avail. I didn't want to pry too aggressively and ruin the nice new paint job. I tried the release lever several more times, but the door would not pop open.

    I had half a tank of gas, and wasn't planning a weekend trip, so I just waited until I could bring the car back to the shop when it opened this morning. The shop owner asked me to hold the release lever while he pried on the door. "Pretty hard to do this yourself," he said. Yep, a two man job. The panel beater came out and had a look, while the owner used his reader to decipher the CHECK ENGINE code. Of the four choices, one was a loose fuel cap.

    The panel beater saw the problem. You can see it in this photo. There is a cantilevered spring attached by the middle of these three bolts. This is what makes the door pop open when the release is pulled. Here you see it in the position it is supposed to be in. But the painter, who had removed the door (and the attached fuel cap) had re-installed the spring on the wrong side of the hinge. Mounted there it was not providing any spring force to pop the door open.

    Also, the fuel cap was found to be untightened.

    Problem solved. This was a double fault, and a good thing too. If the fuel cap had been tightened the warning light would not have been activated. I would not have known about the problem until days later, at a gas station perhaps in the middle of nowhere.

    The fix was simple, and of course it really only takes one man to do it. You only have to jam the release lever open, walk around and gently snag the door open. Would you have figured this out?

    Last edited by aostling; 04-13-2009, 07:38 PM.
    Allan Ostling

    Phoenix, Arizona

  • #2
    I tell everyone, do not panic if the engine light comes on.

    If a loose gas cap was on the trouble shooting tree It would be the first thing I would check.


    • #3
      Whoops, double post.


      • #4
        You should also look in your trunk for an emergency release for the gas door. Some cars have them and some don't.


        • #5
          My wifes car, if you tighten the fuel cap one click its fine. Go three or four clicks and the damned thing comes on.
          Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.