(solved) 97 Daytona T595 Misfires Past 4k Rpm

I am more familiar with car ECUs so not sure just how refined the Triumph one are but generally all injection ECUs have a cold start map that changes once the ECU temp sensor reaches a set temp it goes into what is known as closed loop which uses lambda sensor feedback to modulate the correct fueling known a Stoic (ie 14.7 AFR) where this closed loop fueling ends depends on how the manufactures have set it, it then goes to the open loop or fixed map until WOT which uses load (RPM vs air flow/pressure vs throttle position) to scale the fuel map.
There will be fall back maps to take into consideration air and coolant temps there should also be a similar timing maps that use the same feedback as the fuel maps so timing is also modified to suit running parameters and normally would have a knock sensor to prevent detonation when using low grade fuel or fueling problems.

Any part of this can be affected by one of the mentioned sensors giving incorrect/unsuspected feedback...the ECU coolant temp sensors usual default if faulty is for the ECU to modify global fueling to run quite rich for safety this gives rise to good cold start but bad hot start and running problems at certain engine loadings like cruse and minimal throttle openings.
The air temp sensor will do similar if faulty/out of expected range and TPS set wrong will usually cause similar bad running due to a global shift in map reference, A bad air pressure/flow sensor will just make it run bad full stop as it has to fall back on either TP or RPM for reference signal.

Sorry for the long winded explanation but
Without fault codes its a bit of a minefield to diagnose as they can all cause similar effects and from what i have been told the bike ECUs are not as sophisticated as the cars equivalent.

I have known car crank position sensors to be a real pain and be very intermittent without fault codes which make then very hard to find the problem but as you have replaced yours i doubt that's the problems .....lets hope its just down to coils.

 

This model has a couple of very simple 'cold start' map amendments, with an enrichment table that adds additional fuel at lower engine temperature and another that increases the controlled engine rpm based on engine temperature.
There is NO closed loop control on this model - no O2 sensor.

 

Not sure why triumph bother with lambda feedback on some models as its stops at something like 1200RPM guess its just emissions based.

So it just has a lower rev limiter during warm up, if not faulty coils which i doubt then it does sound to me like there is a faulty ECU temp sensor and the fueling is staying rich which would cause the bog down when the engine is hot.

 

No, it has a higher idle speed

 

Ahh right so you mean ICV?

 

Yes, it changes the idle speed by controlling the Idle Speed Control Valve (later called Idle Air Control Valve)
From about 2005 on, with Keihin ECU, the Idle Speed control is not by controlling air through a valve, but by a stepper motor that directly opens the throttles to control the idle speed (again based on coolant temp, just a different mechanism of introducing more air)



The Warmup table looks very similar except instead of rpm it has an enrichment factor (fuel multiplier) based on temperature

 

If its pissing you off that much it may be time for a change however i know it must grate to admit defeat hope you get to a solution that doesn't drive you mad in the process.

 

Don't give up !! Just imagine how pissed you'll be when you see the other bloke racing around on it, loving every minute, after he gets it fixed! If it started playing up after you changed the seals, it must be something to do with that. When you feel less stressed with it, go back and strip it back down. Check there's no bits of broken seal in the connectors etc. There's always a reason.

 

As i said not familiar with that bike can you post a pic or the relevant page from a manual?