Tune ECU / PCV Question

Hi all, just looking for some confirmation with this and please correct me if I'm completely wrong here (its a bit long winded but trying to get my head around this).

The standard computer has F and L Tables with an FL Switch based on throttle position and RPM. These determine the air mass that gets sucked into the motor, the AFR then determines the correct amount of fuel to go in and controls the injector pulse.

The PCV (with AT) map appears to only seems to have target Air/Fuel ratios (AFR), a % fuel adjustment and % autotune trim.

Does this mean the ECU still controls the ignition advance/retard?

And to my mind the PCV interrupts the fuel injectors and controls the injectors pulses and that's about all? Does this mean the map in the ECU still determines the air mass and pays a large part in general performance and is only "trimmed" by the PCV?

If this is not the case and the PCV takes care of all the fueling requirements does it only have the equivalent of the F table in the ECU?

Think I had a poor dyno tune a while ago as I was warned if I left the AT turned on my bike would probably lose some power. The map looked pretty similar to what I went into the dyno shop with. I reloaded Hanso's zero map and turned the AT back on and the performance got much better. I'm tempted to go back to the dyno shop, pay for a straight HP run then show them the result and ask them to explain, my ass dyno says its much better all round.

Any technical advice, web link appreciated.

Thanks in advance

sleeves said:

Hi all, just looking for some confirmation with this and please correct me if I'm completely wrong here (its a bit long winded but trying to get my head around this).

The standard computer has F and L Tables with an FL Switch based on throttle position and RPM. These determine the air mass that gets sucked into the motor, the AFR then determines the correct amount of fuel to go in and controls the injector pulse.

The PCV (with AT) map appears to only seems to have target Air/Fuel ratios (AFR), a % fuel adjustment and % autotune trim.

Does this mean the ECU still controls the ignition advance/retard?

And to my mind the PCV interrupts the fuel injectors and controls the injectors pulses and that's about all? Does this mean the map in the ECU still determines the air mass and pays a large part in general performance and is only "trimmed" by the PCV?

If this is not the case and the PCV takes care of all the fueling requirements does it only have the equivalent of the F table in the ECU?

Think I had a poor dyno tune a while ago as I was warned if I left the AT turned on my bike would probably lose some power. The map looked pretty similar to what I went into the dyno shop with. I reloaded Hanso's zero map and turned the AT back on and the performance got much better. I'm tempted to go back to the dyno shop, pay for a straight HP run then show them the result and ask them to explain, my ass dyno says its much better all round.

Any technical advice, web link appreciated.

Thanks in advance

Click to expand...

All true. PC takes the pulse from from ecu and trims it, period, the end. The ecu's base tune determines flow from the map at low throttle, where it uses the L tables for fuel, or from the angle of the throttle plate at higher throttle where it uses the F tables. Where it switches is controlled by the F/L table. The PC doesn't know what the ecu is doing. Unless you've got hotter cams, there's no reason to change the ignition, other than to copy the I3 table into I2 and I1. If you have AT turned on, you can't go the dyno tune route. It will change the trims the tuner determines. A good tuner imo is the way to go.

dougl said:

... A good tuner imo is the way to go.

Click to expand...

I agree completely Doug, but that is our problem here, getting a Tuner who knows what he is doing.

A few confused principles in your understanding of the stock ECU, but your understanding of the PCV function is correct.

The ECU doesn't determine the air mass, that is done by the throttle plate, the numbers in the F and L tables are the air mass for the given throttle position and RPM. That value leads to a fueling amount using an algorithm. Then that value is modified by Barometer reading, air temp sensor, and long/short term fueling trims. After all that the duration for the injector is calculated and it fires.

Your determination is correct, the tune you got was probably jacked, but leaving the Autotune enabled with a 10% authority should have NO long term adverse effects, unless you nonstop "accept changes".

Claviger said:

A few confused principles in your understanding of the stock ECU, but your understanding of the PCV function is correct.

The ECU doesn't determine the air mass, that is done by the throttle plate, the numbers in the F and L tables are the air mass for the given throttle position and RPM. That value leads to a fueling amount using an algorithm. Then that value is modified by Barometer reading, air temp sensor, and long/short term fueling trims. After all that the duration for the injector is calculated and it fires.

Your determination is correct, the tune you got was probably jacked, but leaving the Autotune enabled with a 10% authority should have NO long term adverse effects, unless you nonstop "accept changes".

Click to expand...

How does the throttle plate calculate anything?

It doesn't calculate, but it does regulate, via your right hand much air enters the motor. The ECU doesn't dictate anything to do with airflow, aside from secondary plates, it only references how much SHOULD be there, based on knowing how much air mass (tables), the engine flows at a given RPM/throttle position.

ECUs that dictate airflow are ride by wire systems where you are asking for a certain throttle position, which, it may or may not give you depending on coding.

Nothing in the rocket measures the amount of air entering the motor, nothing. The fueling is all done based on how much SHOULD be there, thus MAP based system vs a MAF based system. That is why small things require a remap, because small changes the amount of flow vs what the ecu thinks is there, a MAF system would adjust within a set limit, automatically.

Claviger said:

It doesn't calculate, but it does regulate, via your right hand much air enters the motor. The ECU doesn't dictate anything to do with airflow, aside from secondary plates, it only references how much SHOULD be there, based on knowing how much air mass (tables), the engine flows at a given RPM/throttle position.

ECUs that dictate airflow are ride by wire systems where you are asking for a certain throttle position, which, it may or may not give you depending on coding.

Nothing in the rocket measures the amount of air entering the motor, nothing. The fueling is all done based on how much SHOULD be there, thus MAP based system vs a MAF based system. That is why small things require a remap, because small changes the amount of flow vs what the ecu thinks is there, a MAF system would adjust within a set limit, automatically.

Click to expand...

Thanks for that explanation, I think I finally get it. I have been trying to understand the relationship between ECU and PCV + AT and would really like to find a tuner that can tune with just TuneECU. The PCV seems totally redundant to me.

The ecu doesn't dictate

Rocket3Pilot said:

Thanks for that explanation, I think I finally get it. I have been trying to understand the relationship between ECU and PCV + AT and would really like to find a tuner that can tune with just TuneECU. The PCV seems totally redundant to me.

Click to expand...

There is a good tuner named Nels in Woodinville, WA who can tune your ECU with TuneECU. If you can't find a tuner who can work with TuneECU or Tuneboy, you can either use someone else's map or have your afield trimmed with a Power Commander or similar piggy back. Fortunately I have a greater tuner in my town who dyno tuned my PCIII resulting in peak 152 hp and 162 ft lbs. And smooth as I could want. I'd like to see anyone do better with autotune than with a good dyno tuner.

You guys are Legends just the info I needed. Thanks again for the intelligent feedback here.

Claviger, this is what I needed to hear. I figured the ECU could not "calculate" air mass and this was just a loaded value maybe didnt make that clear.

Last question, am I correct in assuming then that the PCV will not know if the bike is running off the F or L tables as its simply trimming the reading based on the O2 sensor in the exhaust?

The ECU doesn't determine the air mass, that is done by the throttle plate, the numbers in the F and L tables are the air mass for the given throttle position and RPM. That value leads to a fueling amount using an algorithm. Then that value is modified by Barometer reading, air temp sensor, and long/short term fueling trims. After all that the duration for the injector is calculated and it fires.

Dougl

In regard to dyno tuning over here I've given up, when I come into some money (dreams are free, I'm coming to the US and going to buy a Dyno and hopefully get some decent training on it). One gut I tried to book into for a tune said "Oh I don't take bookings, you've got to drop the bike off an I'll call you when its ready (this is no good as I live out in the whops and got no way of getting back). Couldnt give me a date when he was free coudlnt give ma an idea of how long it would be. I gave up and went the Harley dealer who worried me when I handed the bike back and he said "Its pretty powerful" (I knew that already we all do) Think they took one look at the first run and said "She'll be right mate" and handed it back. I've given up now on supposed "tuners" hence the PCV & AT.

Also from what I'm understanding now, unless the tuners prepared to get into the ECU the PVC not going to give the best it can as the ECU is still playing a big part of the mapping?

Think I'm going to start experimenting with the ECU maps again with the PCV AT turned on and see how I go.

Thanks again guys.

Late reply been watching delayed coverage of NBA, Thunder vs Warriors and watching Steve Adams (Kiwi bloke) get kicke din the nuts for the second time in two games by the same guy, hilarious, but not for him....

My suggestion if you don't have access to a dyno right away I'd to zero the PCV, go for a ride with AT enabled, giving it 15% authority enrichment/enleanment. A good hour or more ride trying to hit as many situations as you can, high rpm, low rpm, cruise in each gear etc.

Accept those changes. Then cut authority down to 10% enrichment and 6% enleanment, don't accept changes any more, just leave AT enabled to fine tune it each time you ride.

This is assuming you have the optional input as speed and are using the "by gear" option in pc-v.

This should get you a good running bike that's very close on your afrs.