I'm tryingto troubleshoot a problem with a 2002 Viper. It seems like the spark may be weak because it fouls plugs quickly and the idle fluctuates up and down. I've cleaned the pilot, mains and air jets and adjusted the air screws to stock setting, adjusted the oil cable. It still ran rough at low speeds and would foul plugs and backfire. So I replaced the carb rack with spare set of carbs, changed the fuel pump and that didn't work so I replaced the coil pack and it ran better but it's still eating up plugs and when I ground the plugs tothe head and pull it over they spark looks weak. Is it possible that this viper has the mainwire harness rub through problem or possibly a weak stator? Any ideas???
Oh yeah I also changed the reeds to another set I had and that didn't help either. The other strange thing is when it starts to die out I hit the choke lever and the rpm comes back up to normal 1,700-1,800 rpm . It will back fire loud through the exhaust when I try to start it after it dies. I pull the plugs there is usually one or two which are fouled wet and won't spark.
could be a weak stator, try and unhook both headlight bulbs and undo the rear tailight harness and start the sled, see if it runs any better, this way all you power will go to the ign system.
Rich Empie
New member
My 03 viper seems to same problem. Cleaned carbs its a little better. I need to clean the powervalves next. Let me know if anyone has other ideas. Thanks Rich
When you take off the exhaust to do your p.v.s. have a good look at the pistons, if any of then are damaged you will see it then...also do a leak test with propane, could have a seal leak...also hold you throttle at the pin joint tight to your throttle block & then squeeze the throttle lever, see how this changes anything...symptoms point to t.o.r.s, but with the fouled plugs I think you may have seal leak causing a lean condition & which it creates a hot environment inside a cylinder giving it detonation, causing your backfire…HDRK said:
mod-it
Member
Not trying to insult you or anything, are you POSITIVE you got the carbs clean. Lord knows I've done it. Pilot jets can be a PIA to get clean sometimes. I can't remember the last time I was able to clean them with carb cleaner or air. I always have to run a small wire through them before I can see that the hole is nice and round when looking through it held up to a light. You can even get them clean, but if you don't clean all the passages something will come out of there and plug them up again. Having the idle jump up when you hit the choke is a very strong sign that the pilots are still dirty. Does it run like a champ once its past a quarter throttle?