Fix To Deuce Check Eng Light Problem

Discussion in 'Engine, Fuel and Exhaust' started by rosankyharleyman, Jun 29, 2008.

    I posted a thread back on June 9 about my 2003 Deuce check eng light coming on at full throttle only. I had no codes in my ecm and it was suggested that I replace the plug wires. I at the time had a 2003 wide glide and decided to swap plug wires to find out for sure. In the process I noticed one of the caps on the spark plug was unscrewed and I tighted it up and changed plug wires... Guess what no check eng light, so I was selling the wide glide and swaped the plug wires back and still no check eng light. I guess the problem was the little cap or whatever you call it on the end of the plug being loose was causing the problem all the time. Just wanted to let everyone know in case they have the same problem. The check engine light would not come on till I went into the full throttle position. I could back off just a little and still run on up to 90 with no problem but the instant I went to full throttle it would come on and stay on for about a minute. I checked the codes and found none.
  1. glider

    glider Veteran Member

    That's enough to do it. The ION sensing works on a resistance theory in the secondary ignition system and if that plug tip is loose, it increases the resistance and will usually set a code. Obviously it was only lighting your light without setting a code which is very odd.

    I've seen this a few times too.