In a previous post I was having some timing problems in the low KPA areas under light load. After playing around a little I'm finding it's because the VE's are unstable in those areas.

My bike is cable operated and the VE's are based on TPS and not KPA. Auto tune does not have a minimum or maximum TPS setting. It only has minimum and maximum KPA settings. I cant filter out the lower TPS settings when auto tuning so the Ve's keep changing at 1-5 percent throttle opening position because of deceleration events . How can I keep auto tune from logging at certain TPS points ?

Thanks folks

 

Well deceleration events are anytime the Map is less than your MAP at idle (give or take the stupid amount it wobbles around as reported by the PV) ...so you could set that in the PV autotune settings

...but it does run in some of those cells so how are you going to tune the VE for them without any data??

MAP vs TPS VE tables is a bit of a debate apparently but the problem with TPS is airflow varies quite a bit at any TPS opening ...and in my head it is the airflow that needs a certain amount of fuel ...NOT a throttle position. Anyway, I have a 358 config so seem to be stuck with TPS.

If you have a look at any cell in a VE TPS table, and log what MAP values were seen in that cell you will find that the MAP varied by 20 to 30 kpa or so (if you ignore transients) !!!

[e.g. I'm looking at my last log and the 2000rpm 5% tps cell recorded kpa from 23.6 to 57.5 ...no wonder the VE isn't stable - go out for a different ride on a different day you will pretty much definitely get a different number.]

...and that's nothing to do with timing

 

What you explain makes sense. The problem being with everything varying in that range I get these knocks showing up. I don't hear them, they are showing on the gauges. Whats funny is auto tune detects them and wants to pull the timing. So I guess my question really is how do I know what the VE values should be at that range so I can just manually set them and walk away. Then when ECM detects those knock events wont it keep trying to retard timing ?
I really respect your answers Gordon61 and I thank you for your time.

Edit I just read your other post about minimum spark hysteresis. Thank you for that.

 

Everything varying is not why you are getting knocks showing up ... two different challenges I would suggest.

Do not use spark tuning in the autotune feature ...it doesn't work and is just wrong!! ...or at the very least, outright unhelpful and misleading.

The best you can tune your VE tables is getting the values in the centre of the variations that inherently exist due to that being how the engine works and the delphi strategy that is programmed.

The Pro's talk about tuning your VE so that you are in the centre of a CLI of plus and minus 3% (CLI being the closed-loop delphi system using feedback from the O2 sensor to keep the fuel delivery fine tuned at all and varying times)

What I found however is that for a VE(TPS) calibration there is just so much variation in conditions for each rpm/tps cell that "within 3% is a bit of a stretch of the dynamics of the system and I would like to see anyone get remotely close to that riding around under real conditions on the street.

The point you are aiming for ( I think anyway) is simply getting the VE value in the middle of whatever range of activity is normal/possible for any cell.

If your CLI is plus and minus the same amount then you have probably done the best you can ...in the middle is in the middle, right??

In my example taking a decent sized and varied riding log, I could get it down within plus and minus 8-10% at lower revs getting much tighter at plus and minus 2 or 3% at higher revs. Nobody told me that was wrong and I simply can't see how the physics could possibly improve that situation.

Now VE(MAP) based tables I can see CLI being much better achieved ...I'm probably wrong on that as usual tho

There is no point manually setting VE cells if you are running a closed loop control system that is managing the fuel ...CLI and AFF will simply pull it back to whatever the O2 sensors see anyway ...although did you say you were using a fully open-loop map for some reason?

 

If you got your PV from Fuelmoto, is Jamie not helping you out with a pukka map?

 

Come on now Gordon, it's auto tune................. just plug it in and go . That's what they told you right

 

What's hysterical about that one is they actually say NOT to use it ??!? Seriously? this is the general public ...hello? ...anyone in there?

I know, I know, don't rock the boat or they might have to ban me ...good job I didn't say what I was really thinking