| Help Please - 998 Misfire Woes
Hi Guys,
Apologies in advance if this post is a bit long, but I want to give all the details so that anyone with any advice for me knows all the relevant info.
The bike is a 2002 998 Bip, DP performance upgrade kit, PC111.
The problem is that when the bike revs to a certain point, the ignition seems to cut completely for a moment, resulting in backfiring, and the motor not revving any further.
The misfire starts at about 5,750 revs, and seems to come down a little to 4,750 as the bike gets fully warmed through (15-20 mins). At lower revs, the motor runs perfectly.
The problem first occurred after giving the bike a good wash and clean. It went away after a few days, so it seems pretty certain to be water ingress somewhere. A couple of weeks later, cleaning again after a very wet ride, and the problem is back, and now it is not going away.
Further info:
• The rev counter instantly falls right down when the misfire ocurrs, well below the drop in revs.
• Other electrical components, headlights, instrument lights are not affected.
• I have isolated the Power Commander and re-connected the original loom to the fuel injectors, but the problem is still there, so it’s not the Power Commander.
• Both cylinders are affected.
• I have removed the plugs, plug leads, coils, disconnected every electrical connector I can see/reach, cleaned all connectors and liberally dosed with water dispersant spray.
• For once, it is not an intermittent fault – eg: I can start the bike in the garage, warm her up, and the symptom is easy to demonstrate revving the bike on the stand.
I am reasonably handy with mechanical tasks (I can strip/reassemble a chassis and remove/replace a motor competently), but I am useless with electrical problems.
The last time I had a misfire type problem, it cost me over £800(!) to find out I had a dodgy Power Commander fitted, so I’m hoping that someone may be able to give me some pointers where to look to try to diagnose the problem.
Any advice or questions to help solve the problems will be gratefully received.
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