pgmfi.org

id like to start a thread where we can have a storage place for answers to frequently asked questions, general tips/tricks, how-to's, etc...

if you have questions, links or any such information as far as TurboEDIT usage goes...please post it up. i will try to keep a listing of all the information in this first post so its easily searchable.

Fuel Multipliers
Launch Control
Extra Tables Plugin

how do fuel multipliers work?

1. the fuel tables are stored as 1-byte values that can range anywhere from 0 to 255. (512 values in total)
2. the column fuel multipliers are stored as 1-byte values that can range from 0 to 4. (30 values in total)
3. the fuel value used by the ecu is actually a 2-byte (hi-byte followed by lo-byte) value. math is done to the column fuel multiplier and table value to get the 2-byte values. look at the asm file under L3447: for more information.

if you look at the attached picture, the following rule comes into play...

higher column multiplier = higher possible pulsewidth, lower possible accuracy.
lower column multiplier = lower possible pulsewidth, higher possible accuracy.

TE now accounts for the changes in fuel values...and assigns the lowest possible fuel multiplier to each column. so basically now that you know how this works...you dont even have to know it exists anymore.

how does the current launch control work?

from the rom editor point of view...you are changing the values for launch control rpm and launch control vss and on/off.
the rpm used is the 2-byte value so you have a hi-byte and a lo-byte.
the vss used is the 1-byte value, 0-255.
the on/off is a 1-byte value, 0 or 1.

on the rom itself, the launch control code is in series with the revlimiter code (part of the revlimit routine).


so to walk thru the code in basic steps:
1. the data pointer looks at 7FF8h (where the on/off value is stored).
2. if its off (0), then we skip the code entirely (step 4). otherwise it points to the next bit which happens to be the launch control vss setting.
3. if the value of the vss sensor is above our launch control vss setting, then we skip the rest of the code entirely (step 4). otherwise we change the 2-byte rpm (which is stored in R6 and R7 at this point) to whatever our launch control rpm setpoints are.
4. then we continue on with the next segment of the revlimit code, which is the boostcut...because this is actually rpm based.

easy!

problems: because this comes after the actual revlimit code, if you have the cold or hot revlimit lower than the launch control rpm (and the launch control turned on)...the launch control limiter becomes your new total rev limiter. this will have to be fixed in the future.

wow, your explanation are so professional

Great work ! ill be waiting for more updates!

extra tables plugin:

i will add to this when i get more time, attached is a small writeup of how things work.

Can`t wait!Want to tune my cold idle for better economy.

Interesting!A little bit scientific for my taste:) I would also request (if possible) a 'scenario' explanation/FAQ....'let`s say you have this problem, this is what you have to do on extra tables in order to fix it'.No rush on this You`ve already gave plenty for the community.

A 'scenario' that always happens on my car during cold start is this:

The car starts fine but the AFR is 15-16 for 30 secs (1200 rpms), then slowly goes to AFR 12-13 (1600 rpms) and gradually warms up down to 800 rpms ( AFR 14.7).What settings do I need to tweak on extra tables in order to have a better cold starting and smoother AFRs?I know that I have to tweak the IAT/ECT pulsewidth but by how much?The temp outside is around 22 Celsius.Do I leave 1.00 around 22 celsius and gradually increase the pulsewidth if the temp is colder outside?But what about that brief moment when the car cranks and the AFR is 15-16?Is there an option to tweak that in extra tables?I know that crome would be better on this but oh well

Thanks

your fuel multiplier should be the following:
multiplier = actual AFR / target AFR

use the following if you are adjusting a multiplier:
new multiplier = current multiplier + (actual AFR / target AFR) - 1

if your watching the afrs change like that while warming up (at idle), then i would go into the ECT fuel multipliers and from left to right change the values to 1.05, 1.05, 1.05, 0.90, 1.00, 1.00...see if that helps correct the issue. there is no right answer to this, because there are many combinations of multipliers and fuel table values that can be used.

That makes things a lot clearer for me! Thank you for the explanation.I`ll try to play around with the multiplier now that I have the 'secret formula'.Hopefully the AFRs will stay constant during warming up.

I`m not sure if this is a TE problem or a vacuum problem with my car.

The car starts fine but it stays on 17 AFR for 2-3 minutes, then all of a sudden (I mean in a split of a second, like you press a button and everything works!) it goes to 12-13 AFR and stays there until it warms up to 14.7 AFR.No matter what ECT multiplier I`m using, that period of 2-3 minutes that the car runs on 17 AFR is bugging me! Is this a problem with TE or is this a vacuum leak?It doesn`t seem like a vacuum leak.

thanks

That does seem really strange.

The "VSS" mentioned above, is that the speed sensor in the instrument panel?

I have a track only autocross car (1991 CRX) and I would like to use the launch control function, but my car has no instrument panel. Will the launch control still work with no instrument panel? If not, any thoughts on how to simulate the missing signal, perhaps off a clutch switch.

No, it won't, but, you can wire in a VSS from a 92+ civic, which will work and feed the signal to the ECU. In fact, this is the only way to do ANYTHING by gear because the speed and rpm are used to calculate the gear (also tire sizes and gear ratios).

This transmission mounted VSS worked out well.

I am getting alot of wheel spin, right up to the rev limiter in 1st gear. I will try lowering the launch RPM (at 4k now). However, it seems like if there were a tuneable gradient from the launch RPM to the primary rev limiter, it would control wheel slip better. Would something like this be an option?