SD = Low Cylinder Airmass?!?
Thread Starter
TECH Senior Member
iTrader: (4)
Joined: Apr 2003
Posts: 6,249
Likes: 3
From: Long Island, NY
SD = Low Cylinder Airmass?!? I just noticed that when Im running in SD My cylinder airmass is about half what it should be. I idle in the .08 g/cyl row, and WOT tops out on .44 or .48.
Going over my logs with the MAF, I can see I idle at .16 g/cyl and my WOT goes to .88.
I dont get it, whats the deal? I must have played around with the wrong setting somewhere...
Going over my logs with the MAF, I can see I idle at .16 g/cyl and my WOT goes to .88.
I dont get it, whats the deal? I must have played around with the wrong setting somewhere...
Thread Starter
TECH Senior Member
iTrader: (4)
Joined: Apr 2003
Posts: 6,249
Likes: 3
From: Long Island, NY
Originally Posted by SSpdDmon
Hmmm...are you logging the right air mass pid? I know in EFI Live we have one for MAF and one for SD. Is it a unit conversion issue (grams vs. ounces)??
One thing that coincided with the change is I used to lot "Mass Air Flow (SAE)" but now just lot "Mass Air Flow". The former used to read numbers even if MAF fail was set to 0. The latter simply reads 0.00 when MAF fail = 0. Im not sure if that was taken into account when logging.
I cant really tell if this is a logging problem, or an issue with the tune itself. It looks like my WOT timing is around 27 or 28, which is where it should be at .88 g/cyl. Otherwise timing would be closer to 35* if it was actually following the .44 g/cyl row. This leads me to believe only the logging is affected, but I would like to be certain since there are potentially disastrous effects.
Thanks,
-Tony
Thread Starter
TECH Senior Member
iTrader: (4)
Joined: Apr 2003
Posts: 6,249
Likes: 3
From: Long Island, NY
Okay, playing the log file back at a slow pace, I noticed that the correct values came up in the table display, yet the histogram appeared to be halved. So now Im sure its a logging issue and not the bin. Further more, its isolated to the histogram.
Looking into the histogram, I notice its reading from the "Timing Advance" sensor which Ill bet is a custom PID that averages MAF and Dynamic Airflow. Since the MAF reading is all 0.00, its effectively cutting the reading in half.
Ill log MAF (SAE) instead of just plain MAF and it should work.
Looking into the histogram, I notice its reading from the "Timing Advance" sensor which Ill bet is a custom PID that averages MAF and Dynamic Airflow. Since the MAF reading is all 0.00, its effectively cutting the reading in half.
Ill log MAF (SAE) instead of just plain MAF and it should work.
