How To: Add Pressure Input for PC-V

[barbagris]

I will have to have a serious log/sample session. At low throttle it is running leaner than before - but if I whack the throttle it whiffs of unburned fuel. I NEED DATA.

 

[Claviger]

The question is, does it run better and was it overly rich at low throttle before?

The MAP based trim table in mine had some significant values of added fuel and some significant reductions, 15% and 20% in some areas, on a tune that ran pretty well already using TPS.

Remember, during transient events, like rolling on throttle, it shouldn't be at 13:1, it should and will dump extra fuel to give best throttle response characteristics. Down into the 11s and 12s wouldn't surprise me to give the best feel and throttle response for a brief period of time during enrichment period and it should slowly lean out back to 13ish as the enrichment timer expires and the multiplier for extra fuel fades falling back to only the table values.

Low throttle/RPM I'd suggest just make sure it's not dangerous (so 14:1 or under) and from there tune by feel not ratio.

Below you can see during the enrichment function, the top graph, MAP signal, doesn't change a whole lot. The built in TPS rate enrichment function in the ECU does the enrichment work.

 

[barbagris]

Seen AFR down in 15's and 16's but at 0-1% throttle and under 2000rpms - Overall MUCH better, really.

But it is now discovering why I get below 10 occasionally. I forgot to add pressure to the logging

Rolling on seems to DUMP more than WHACKING open. Like I say - I NEED DATA. OBSERVE-UNDERSTAND-MODIFY.

 

[Claviger]

15s and 16s is worrisome. I'd probably go in and add fuel in the TPS portion to fatten it up, like 7% at least in the portions it's swinging that lean, and let the MAP control fine tune it.

Roll on vs Snap open: The roll on will swing richer as the increased air isn't as much as when going fully open quickly. When you open it fully quickly, it's going to use the max enrichment value the ECU can output and it's the right amount, under roll on conditions, it's doing a best estimate, which tends to be a little too rich.

 

[barbagris]

15s and 16s is worrisome. I'd probably go in and add fuel in the TPS portion to fatten it up, like 7% at least in the portions it's swinging that lean, and let the MAP control fine tune it.

Roll on vs Snap open: The roll on will swing richer as the increased air isn't as much as when going fully open quickly. When you open it fully quickly, it's going to use the max enrichment value the ECU can output and it's the right amount, under roll on conditions, it's doing a best estimate, which tends to be a little too rich.

Will be out logging later - See what the data says. The 15's is when the stock ECU L tables are un-fettered by PCV control almost certainly

 

[barbagris]

OK I have data - I am happier now. I would say on the whole a wee bit leaner than before (TPS tuning) but save some odd overrun moments - where the 15's appear - Nice range of numbers. low 14's to mid 12's. Low 14's and High 13's predominate - esp on weighting numbers.

My riding conditions GENERALLY are very binary.
VERY poor roads with speed bumps (0-2TPS) or fairly open and fast-ish roads(10-25 TPS).

But today I was forced to trundle in traffic a bit and so, naturally, was FORCED [honest officer] to also whack the beast open to get past. Changing up 3rd to 4th at 5000rpm-ish I got a little squeal from the rear tyre. And I am NOT prone to quick-shifts. Torque - pure and simple. No idea how fast - but the barbagris alert-o-meter was flashing like a firefly orgy.

WIth an Autotune and your AFR targets and the MAP tune - I NEED A BLOODY SHIFTLIGHT .
Fortunately when I upgrade the fine/jail alert-o-meter to the new hardware - I will have a shiftlight sat free.

The way to look at this is - the throttle does just that - THROTTLE (i.e restrict) not enable.

Again thanks for "enabling" me.

 

[barbagris]

Enable the Pressure Sensor and add your voltage to MAP relationship. For my sensor the values were:
4.05 Volts = 997 HPA
2.44 Volts = 590 HPA

For those of us who do not think in American measurements - And with a lot of assistance from Rob.

Be aware that when calibrating the two sensor voltage points - you HAVE to ALSO convert these to PSI - If like me you input hpa values then although the PCV - A/T does actually work - you will never manage to correlate TuneECU or the PCV AFR tables with the logged data. And the trimming is very exaggerated at extremes of the table.

With a bit of luck I can get out tommorow and do another "proof of Concept" logging run.

 

[Ishrub]

I'll be back with a lot more questions when mine arrives and if I decide to use this stuff.
Or more likely just hand it all over to a guru and observe for interest, then ride.

For those of us who do not think in American measurements - And with a lot of assistance from Rob.

Be aware that when calibrating the two sensor voltage points - you HAVE to ALSO convert these to PSI - If like me you input hpa values then although the PCV - A/T does actually work - you will never manage to correlate TuneECU or the PCV AFR tables with the logged data. And the trimming is very exaggerated at extremes of the table.

With a bit of luck I can get out tommorow and do another "proof of Concept" logging run.

Convert Hectopascal to Psi - link.

Enable the Pressure Sensor and add your voltage to MAP relationship. For my sensor the values were:
4.05 Volts = 997 HPA = 14.46 psi
2.44 Volts = 590 HPA = 8.56 psi

 

[barbagris]

It really is a piece of cake. @Claviger has done all the hard work for us.

 

[rash_powder]

I am working on building this MAP table per advice given by @Claviger. The table is setup in PCV with the pressure numbers he gave across the top - however they don't convert the same as I have.....

For example, the last two columns I have in my TuneECU file are 970 and 1010. Those convert to 14.07 and 14.65 psi respectively. I hope I am not missing on some math regarding this. The converter I used was Convert Hectopascal to Psi

2nd question is, I just copy the values from TuneECU to PCV? IE - My 1010 hpa column (the last) at 7000 rpm shows 8884. I just transfer 8884 over to PCV? What unit is the 8884, out of curiosity? rpm/hpa?

Many questions from the village idiot, I know. Once I get this beast sorted I will bringing home an old Honda CB500T to tinker on. Significantly easier to work on, MUCH LESS expensive if I hose it up, and I understand what is happening in that old engine.

Again, many thanks for the help.