Listers - Since the big fires here in San Diego I had a little time off and could devote some time to figure out what my intermittent miss/backfire was. I figured, since we werent in any immediate danger (the fires were basically burning all around us) I might as well do something to take my mind off of all the destruction etc. This was on my daily driver V6 Spitfire (throttle body FI) that I was going to take to Triumphest in Laughlin, but due to this several month long, on-going problem, I had to resort to the 1970 Spitfire backup vehicle. The problem as it were, was that the car would miss/jerk at random times while driving around. One would never know when this would happen, but usually once a day on some occasions, several times, it would misfire/backfire. Usually at speed, more often than not when just accelerating, but I could never just get it to do it on demand so to speak. It would do this then drive for many miles before it would happen again. After going through the entire electrical system, systematically replacing every component (fuel pump, sensors, injectors, coil, plugs, wires, dist, modules not necessary in that order, but you name it I replaced it etc), and after cleaning the air filter, replacing the fuel filter checking the pump pressure fuel lines blah blah blah, and still having no luck I was at my wits end. Then, just after I had replaced the throttle body and was watching the idle spray I got a misfire (this was the first time I had actually SEEN it happen, not just felt it). This got me thinking about the number three plug that looked just a little different than all the rest, since it was on the intake log of that bank, and I decided to check the valves - Sure enough, the exhaust valve had basically no clearance, and the intake was minimal, probably around .006-8 thou. EUEKA!!! Problem solved! It didnt show up in the compression check because there was just enough valve closure so that at cranking speed I still had compression (a little low, but not out of the ordinary) and apparently would have to bounce just enough, and at the right time, to ignite the incoming mixture and shoot the flame back up the intake track which is what I saw.
As usual, I figured it was electrical because it was so random, but it just goes to show you, not all random problems are electrical or fuel related - they CAN be mechanical! Frustrating to say the least, but sure nice to have the problem fixed. So now I have my Spitfire back (I ran in to the house, after I discovered the problem, and did the little victory dance that my wife found most amusing). The fires are becoming more under control, and most people are getting back to their homes, at least those that have homes to return to and things are slowly returning to normal! So I had my victory brew (a Carl Strauss Amber Lager) whilst cleaning the car of ash and soot, (yeah, it even gets inside the garage) and am now able to install the new molded carpeting I had purchased but was not ready, or felt like installing, and can start doing the fun stuff for the vehicles!! Barry Schwartz San Diego (La Mesa) CA -------------------------------------------------------------------- mail2web - Check your email from the web at http://link.mail2web.com/mail2web _______________________________________________ [EMAIL PROTECTED] [email protected] http://autox.team.net/mailman/listinfo/spitfires
