ignition timing

[05typeR]

i really just need a quick idea on this problem since while im at work i cant check the car. . .
while cruising around 2000rpm, very low load an9d throttle opening my ignition is normally around 33 degrees but at times i felt the car do lurch forward, i didnt a datalog of this event (sorry i dont have it with me to up load) and i saw the ignition timing jump from 33 degrees to like 5 degrees then back and forth for like a second or so. . .during this time my engine RPM remains relatively stable.

it had me thinking it maybe my crank sensor but this event should have also affected my engine rpm im thinking. . .and based on the honda manual ignition is ECM calculted.

did anyone come across this problem with the K20 motors?

im using a PRB ECU with a V3 board nothing electronic has been changed on the car for months.

[05typeR]

this is basically whats happening

[Arno]

That's usually the acceleration smoothing retard kicking in. It has a very distinctive pattern.

The algorithm inside the ECU can be very/too sensitive in somes cases, so it kicks in even at very tiny rpm/throttle changes, especially if you have modified the engine or are running stiffer engine mounts.

Usually it's fixed by setting the 'Tip in retard duration' table under Parameters -> Gear Compensation Parameters all to '0'.

Can also put -100 in all columns of the 'Tip in retard gear multiplier' table, but I didn't find that a requirement.

http://www.hondata.com/help/kmanager/in ... meters.htm

That should stop it from triggering this and stop the lurching.

Bye, Arno.

[05typeR]

thanks Arno but those setting are already set to '0'.

i found this morning that it happens mainly (or only) under light engine load. . .once i accelerate as if i want to over take i dont feel this happening.

[Arno]

i found this morning that it happens mainly (or only) under light engine load. . .once i accelerate as if i want to over take i dont feel this happening.

That was the same in my case. No problems when actually acceleratng, but at light loads and steady cruise it would 'stutter' sometimes. Ignition timing trace in my case showed the same distinctive 'saw tooth' pattern:



Setting '0' on all coluumns in the 'tip in retard duration' table solved it for me.

If that doesn't work for you, did you try to put -100 in all columns of the 'tip in retard gear multiplier' table as well as '0' in the 'tip in retard duration' table?

That way you're combatting the problem from two angles, reducing the duration of the retard action, as well as reducing the actual retardation it's trying to apply.

Do you experience the same effect on higher gears? (4/5/6) The default settings usually mean that this effect is most pronounced on 2nd/3rd gear cruise and almost non-existant on 5th/6th gear.

If you do see the same in 5th/6th gear then there may be another issue...

Bye, Arno.

[05typeR]

Hi Arno,

I will look into in a bit and let you know, it's a basic PRB map I used with changes only to fuel/ign/cam angles really.

What has me is that just out the blue I started getting this problem.

I don't normally feel it in the higher gears either its not happening then or it very very slight.

[05typeR]

turns out to be the TPS.

back to normal now.