cold start timing numbers

[trinydex]

Folks,

Been working on tuning my idle and startup with hks 272's at -2i -1e. Followed the guide on evoM and raised the target idle speed and have been bumping up the timing. Once the car is warm enough to go open loop the idle is just dandy and the timing numbers seem to come straight from the high octane ignition map.

However, when the car has been sitting long enough to cool down to ambient temps, the timing is jumping all over the place during warmup. I logged a bit last night and saw that it looked to be pulling numbers from the 80% load column, while the ecuload was reading 40% or so. I'm thinking that the obdII / MUT value for load is not updated fast enough and the load is actually jumping from 40 - 80 and back.

Here is a sample:


RPM FuelTrim_Low InjPulseWidth AFRMAP TPS ISCSteps KnockSum TimingAdv
1281.25 98.44 2.048 128 14.51 83 0 10
1281.25 98.44 2.048 128 14.51 83 0 9
1281.25 98.44 2.048 128 14.51 83 0 12
1250.00 98.44 2.048 128 14.51 83 0 9
1281.25 98.44 2.048 128 14.51 83 0 9
1281.25 98.44 2.048 128 14.51 83 0 11
1250.00 98.44 2.048 128 14.51 83 0 13
1281.25 98.44 2.048 128 14.51 83 0 10
1281.25 98.44 2.048 128 14.51 83 0 8
1281.25 98.44 2.048 128 14.51 83 0 14
1312.50 98.44 2.048 128 14.51 83 0 11
1281.25 98.44 2.048 128 14.51 83 0 11
1312.50 98.44 2.048 128 14.51 83 0 9
1312.50 98.44 2.048 128 14.51 83 0 9
1281.25 98.44 2.048 128 14.51 83 0 9
1281.25 98.44 2.048 128 14.51 83 0 12
1312.50 98.44 2.048 128 14.51 83 0 11
1312.50 98.44 2.048 128 14.51 84 0 10
1312.50 98.44 2.048 128 14.51 83 0 12
1312.50 98.44 2.048 128 14.51 83 0 12
1343.75 98.44 2.048 128 14.51 83 0 11



you can take a look at the attached partial screen shot of the highoctane map...

[trinydex]

Actually in closed loop, it'll be rare that the Load calculation will read correctly..

This is what the 1C value is useful for, since 1C is the ECU Load value, and it clips at high boost, it should reference correctly at idle..

Oh, and in closed loop, timing also varies, apparently it uses the value in the cells/columns as reference, but will alter it accordingly, but I'm not sure what parameters it uses..

I have found at least a dozen tables that look to be timing or Fueling related that I Haven't been able to identify..



Intersting,

I have some logs from last night at home, before going to the map above, the low timing numbers were lower in the log from last night. I will play around a little and see if I can't smooth out the numbers by adjusting the higher load low rpm timing targets.

If it is referencing some tables we don't have access to yet then my changes sould not smooth out the timing during warm up.


Possibly, it may be a some fuzzy target, such as maintaining a particular vacuum or load value..


I've been thinking that the ECU may use the low octane map during cold start, or at least some interpolation of the low and high octane maps. I had some drivability problems while the engine was cold after making my low octane timing map a bit more conservative. The problems went away after adding timing in the low load areas of the low octane map. I haven't gotten around to actually comparing the logged timing to the low octane map, so it may just be a strange coincidence.

-Paul