carls1982z

Ive been seaching with no luck too find, information on the following in tuner pro, and a 7747 ecm. on my crossfire.-here they are, with address.---open loop idle on--rpm [2a1], AND, open loop idle off--rpm [2a0], AND ALSO, TIMEOUT AFR VS COOLANT [0427],----I havent been able too locate info on this for tuning reasons and any help would be great.

dimented24x7

iTrader: (2)

Im not familiar enough with the 7747 to say what the first two are. Its not immediatly apparent from the hacks floating around

The timout AFR (actually choke AFR) is part of the choke function. Additional enrichment is added after startup to help smooth engine operation, much like a choke on a carb. This choke is in the form of an AFR, which is subtracted out from the desired AFR to richen up the mixture. Also like a choke, its only present for a short period of time.

carls1982z

SO if i here ya right the higher the # there[timeout]-- the richer it will be cold ?? [choke]

dimented24x7

iTrader: (2)

Yes. The cold choke enrichment only lasts for a max of 30 seconds or so. Use the open loop AFR vs. RPM and cool temp table to adjust the AFR when the motor is cold.

carls1982z

THANKS there dimented.---still would love info on the other ones too, wish i could find.info on them.---they are open loop idle on--rpm, AND open loop idle off --rpm.

HaulnA$$

Those are RPM hysteresis thresholds for open loop idle entry/exit. The "Open Loop Idle Off RPM" should be set higher than the "Open Loop Idle On RPM" by 25 or 50 RPM or so. These settings are designed to provide hysteresis so that the ECM cannot teeter on the open loop idle threshold and rapidly enter/exit open loop idle. It is either in open loop idle, or it is not. For example, say you want to idle in open loop and your desired idle RPM is 600 RPM. You might set the "Open Loop Idle On RPM" at 800 RPM and the "Open Loop Idle Off RPM" at 850 RPM. This way as you accellerate off idle and pass 850 RPM, open loop idle is then disabled and the RPM must now drop below 800 RPM to re-enable closed loop idle. I hope this makes sense.

carls1982z

yes and no on the making sence.---in your example in the end you say drop below 800 too get closed loop re inabled,? shouldnt it be drop below 800 to re innable open loop.???--------also as i look at my bin and see that my #s are open loop idle off, is at 25, AND my open loop idle on rpm is at 50, --was this right in the stock asdu bin ??? ---------AND if you no, dimented said go too open loopAFR vs rpm AND coolant table too adj cold afr.----any idea of thier address ??

vernw

iTrader: (2)

Good info!

HaulnA$$

Yes, you're right, my bad. I should have said below 800 RPM enables open loop idle. As for the ASDU stock settings, they are set to not enable open loop idle at all and instead utilize closed loop idle. HTH