My Voyager is backfiring in the aircleaner at 3700-4000 rpm when i drive it and if the gearbox is in park and i rev it up to the above rpm. It starts to missfire slightly and if i press the gas even more it will backfire so much that i even blown a aircleaner top off. This happens almost everyday but sometimes it will run perfektly. I=B4ve changed wires and plugs whith no change. There is no error code in the "check engine lamp" only 55.
Is there someone that can help me, i=B4m going crazy over this. I=B4ve read a lot about mis/backfiring here, but nobody seems to have exactly the same problem as me. meaning at a specific rpm regardless of load/uphill/downhill/decelerating/in-gear and so on.
Help please!!!!!!!!
Janne
Solution:
The CPS sensor (crankcase position sensor) was to close to the flywheel, and due to vibrations at the mentioned rpm it was thouching the flywheel and give the computer rubbish to work with. This resulted the ignition coils to send power to the sparkplugs at random, creating the hopeless backfiring in the aircleaner. I just removed the sensor, cleaned it up a bit because the plastic body had partly covered one of the two brass pickups on the sensor. Put it back in the hole to the bottom, and pulled it back 0.098 inch (2.5mm) and fastend it.
And it works like a dream again!!.
Janne