CBR6 intermittent FI problem

kramdra · World Chat Champion Joined: 28 Oct 2010 Karma :

Starting from cold, she struggles at 1000rpm for a few seconds before the ECU kicks the FI light on, jumps upto normal 3000rpm fast idle. Getting backfires when I roll off, but otherwise rides fine. After a couple miles she is warm, restarting a few times and everything is normal. Have done about 400 miles since.

Started after some work at weekend, I think that a connector might have been moved or water has got in somewhere or in the tank, as she got washed. Fresh fuel did not help, neither has the hot weather.

Ideas? I will try re-plugging the ecu and engine loom connectors, they have not been disturbed for a few years.

fatjames · World Chat Champion Joined: 09 Jul 2011 Karma :

What work was done at the weekend?

Sounds quite normal TBH, mine will low idle for a moment before building up to high idle. I always assumed it was building oil pressure or something.
(mine is a 2004 CBR600f)

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

As above, what did you do to it?

When WD40 got in my CBR6F FI ECU, it wouldn't start, then ran like dogshit until it all dried out.

I take it it drops back down to a normal idle after the bike has warmed up?

Hong Kong Phooey · World Chat Champion Joined: 30 Apr 2016 Karma :

FI warning light? If so what are the flash codes?
____________________
~~'81 CG125, '97 FZS600~~ : '99 CBR600F4, '09 KTM RC8

kramdra · World Chat Champion Joined: 28 Oct 2010 Karma :

This is still occuring about once a week. Most of the time only lasts 10 minutes and is ok after restarting hot engine. Seems more related to hot weather than anything else.

The work done previously was that I sprayed the forks - in place, swapped the front callipers, rebled, swapped front tire and a wash - and not washed since.

kramdra · World Chat Champion Joined: 28 Oct 2010 Karma :

Backfires seem to indicate the fuelling issue is fixed and its time to restart the engine.

Can not remember how to get ithe das to give flash code.

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

kramdra · World Chat Champion Joined: 28 Oct 2010 Karma :

I seem to get 3 codes as there is a gap between them.

2, 9 and 11.

2 and 9 make sense, they were my suspicions anyway.

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

kramdra · World Chat Champion Joined: 28 Oct 2010 Karma :

Map is the one that has been dangling to the side of the airbox since the weakmounting hole snapped in 2012. Connectors are all good. Vacuum hoses do not appear to be leaking but are old, original and a massive pita to replace.

IAT and the inside of airbox had a light film of fork/crankcase breather oil. Cleaned off.

Briefly happened beforethe journey home. It does seem to be ambient temperature related.

Hong Kong Phooey · World Chat Champion Joined: 30 Apr 2016 Karma :

Hoses tend to crumble with age, even if good internally it still may be bunged with crud.

I'd measure the inner diameter and order some silicone bling.

The other stuff, cleaning including electrical connections. If that doesn't fix then ebay for second hand as I'll bet the new items are expensive.

The fuel economy and power will be suffering if it's fuelling for the wrong air temp.
____________________
~~'81 CG125, '97 FZS600~~ : '99 CBR600F4, '09 KTM RC8

kramdra · World Chat Champion Joined: 28 Oct 2010 Karma :

This did happen with a warm engine but not any more. I am starting to believe it may be the wax fast idle unit siezed, almost always 44c is the temp where I can restart and she is fine. If so, I have no idea how the ecu bumps the rpm up, controls injectors but there is no ecu controlled air valve on these..?

Fuel economy and power are better than ever, she has always liked summer, belive the thermostst is stuck.