Since changing the TPS and solving the jerky low revs issue I thought I'd try swapping some fuel maps today. I have been running a heavily modified and smoothed aftermarket tune but decided to go a different route. The current map has all the alterations done in the fuel map so I thought I'd go back to basics.
I pulled up a standard aftermarket can map and instead of changing the fuel map, I changed the air/fuel ratio map. To explain briefly what this does, the ECM looks at the engine load, throttle position and air temp and pressure and that gives it a reference point on the fuel map. It then extrapolates that value using a corresponding reference value in the air / fuel ratio map to produce the time the injectors should open in milliseconds to deliver the required fuel. I've missed out a lot of other stuff such as ign timing calculations to keep it simple. The ideal air / fuel mix for an internal combustion engine running on petrol is 14.7 to 1, whereas best power is produced by a slightly rich mix at 13 to one. So all I did was change any values that were over 13.5 to 13.5 and leave all the others the same. Mostly these were in the low to midrange ie 1/4 to 3/4 throttle and up to 6000 rpm.
The results were mixed. The midrange drive is noticeably improved, pulling really hard around 4-6000 rpm but the old popping on overrun is back with a vengance and the choppy throttle is back too although not as bad as before I changed the TPS.
So next map will have today's A/F settings, but adopt some of my earlier work on the old problems and see how it goes. :D
:new_popcornsmiley
Hi Bob.
Have you tried Wayne's adjusted A/F map on T595.net (http://www.triumphtorque.com/kb/maps/family/5-Tiger.aspx)? I used that as a base and it was excellent (standard can although there's another there for aftermarket). I've since tweaked it a bit to keep the ECU in open loop (ie A/F <> 14.5) except when idle and load < 25%.
Very smooth indeed on my 04.
I'll have a look thanks!!
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