Hi All,

I have noticed a number of fuel maps that have been created by TTS Master Tune, that during De-Acceleration the Desired AFR goes rich.

I have a 2013 883 Iron using such a map and chasing a problem, so I have created a number of Data Master runs to study.

I have noised that during de-acceleration AFR goes to around 13.5.

Now I thought the logic would be to cut the fuel or have a very high AFR. This is reflected in a number of Automotive papers I have read on the subject.

Why do TTS go the opposite way??

Fritzables.

 

There's a couple reasons. But to your question...what problem are you chasing?

 

G'Day Pine Tree,

Thanks for the reply....

OK.... the issue is, when on a run and up to highway speeds (110 KPH) then come to a stop, the Engine RPM remains at around 2,000 RPM until the bike comes to a complete stop, followed by about 10 seconds before RPM returns to a normal idle speed.

The IAC Valve checks out all OK and I don't believe I use too many Steps associated with the IAC.

I am now think that because I am rich on the Deaccel plus IAC Steps that this is enough to cause the issue.

Mind you this will not happen in all cases though.

Fritzables.

 

This is a known issue that TTS has nothing to do with really. The tuner only controls the idle once at a complete stop. Untill at dead stop you will have a higher idle. You may be able to control it slightly with timing but 13.5 sounds right as the ecm is open loop in the idle map range. If you are running a intake that routed the breather right back into the throttle body it will be a good idea to use some throttle body air intake type cleaner and spray with straw around the port where the IAC is. My 2007 was same way until I sprayed it and was fine after. Check your oil level and keep to below the 1/2 point on the dipstick and that will reduce the blow by that gets routed back into the intake.

 

1. In an internal combustion engine. Decell pop can be caused by too much or too little fuel in the exhaust header. So it can be cured by adding or removing fuel at the zero throttle position or relative MAP location. On motorcycles it is favored to add fuel as this reduces abrupt throttle changes when transitioning from on the throttle to off then back on again. On an air cooled engine it also helps to cool things down.

2. A hanging idle as you describe is usually caused by a lean condition. Check for intake and exhaust seal leaks. Verify correct IAC steps, Then reset AFV.

 

Good Read Gents,

Thanks for the detail.

Better come clean, I am a Mechanic by trade and have built a number of high performance engines - but, they have all had Carbies and Distributors. This is my first go at Fuel Injection and Electronic Control Units, so fully aware about the pops and all that. :-)

I have the tune just the way I like, the thing pulls like a train so I am happy with Fuel and Ignition. I use a 98 Octane fuel so took the initiative of whacking in 5 Degrees of Advance all over - no pinging detected.

I have the Map to a point where I can start and the engine goes straight to Idle with none of the flare.

The only thing remaining is the issue of High RPM coming to a stop.

The only thing I am unsure of is the Warm Up Steps.

I have already cleaned the IAC Port but no change - I did this with the IAC in place - maybe I need to remove it instead??

The Oil Level is always kept to the full mark - maybe I need to review my logic on that?

The bike is newish and bought it last December with only 11,000K on the dial.

Thought about taking it to the Stealer as a Warranty issue but thought is a custom map.....

Fritzables.