Hi VFRworld I've a VFR800FIx which cuts out at 3000 RPM when at a neutral throttle position, all is fine when accelerating through 3000 RPM. When the problem occurs rev counter dies. The problem is proving to be very dangerous while trickling along in traffic or riding through corners. I've re-seated all the connectors I can find but the problem still persists. Any ideas anyone Ian
At neutral throttle position--are you saying when the throttle is closed the engine cuts off and dies? Does this occur as you are coasting down from higher rpm with the throttle closed? Is it throwing any check engine codes? The throttle position sensor generates a signal to the computer for Closed, Part-Open, and Wide-Open Throttle. The computer then uses that signal to calculate the fuel injection pulsewidth, etc. What year and how many miles? Check for cracked rubber hoses that may be leaking air and causing a lean condition that shuts off the engine.
Hi Kennybobby, When I say 'neutral throttle' I mean the trottle is open but I'm not really accelerating or decelerating at a noticeable rate. I feel it is an electrical/electronic issue as I've checked all the hoses and all are in good condition, also the rev couter dies. The engine will then fire once away from the 3000 RPM area.... It's very strange. Re the engine codes, I don't know how to get them!! The bike is a 1999 50th anniversary model. Ian
Here's a post i found using the search feature in the 5th generation forum for 'driveability' http://vfrworld.com/forums/mechanics-garage/21585-vfr-vtec-2008-throttle-issue-another-one.html The other thing i was thinking was that the throttle sensor at the Closed Throttle position may need adjustment. You could put some tape on your handlebar and throttle grip and mark it off for Closed, 1/8, 1/4,1/2, etc. Then notice where the mark indicates when it does the 3000 rpm cutoff. If it occurs between closed and 1/8 then that would point to the TPS needing a slight adjustment to move the onset of the trailing-throttle mode. Carburetors have a internal circuit that does a similar function known as the deceleration enrichment to prevent lean popping on closed throttle coastdown.
