My calculated load doesn't seem correct. Im not really looking at load in ft/lbs but at the main timing table in the scanner. I'm in SD mode. I do not have the 1 bar OS upgrade installed as I plan to eventually go back to the maf. Im aware I need to delete the maf SAE pid to get the scanner to read correctly. My actual timing, without the maf SAE pid deleted, according to the scanner is slow. I'm only seeing 0.56 g/cyl in the table in sd at WOT. The timing in this area of the table is about the timing Im logging with the scanner. The car is slow as well. Before disabling the maf this engine would run much lower down in the table with larger cyl airmass numbers. Do I just need to increase the timing values in the main spark table in the areas the pcm thinks the engine is running now or is there a way to get back the correct load values without re installing the maf? Im also concerned with transmission pressures since the calculated load appears to be so far off. I hope I have attached the tune and the log correctly. Any advise is greatly appreciated. BTW this is a 2002 Camaro with a LS3 swap and a 4L80 swap. The scanner log is a dragstrip pass. Timing with the maf was 30*. Now I see only 25-26* in SD.
Last edited by streetlegal; 07-21-2014 at 08:16 PM.
Your Cylinder Volume is incorrect in the tune. You have a value of 0.82345, and you need to put in a value of 0.77500. Make that change, and then redo your VE table, and you should see some more accurate numbers.
I may have found the problem. I didn't address the IAT timing table. Im still wondering if the pcm calculates load differently or less accurately without the maf.
The PCM definitely calculates load differently without the MAF. The MAF gives the computer directly the cylinder airmass number, but in a SD mode it caluclates it using the ideal gas laws. A huge part of the gas law calculations is the volume of the cylinder, and like I said earlier, yours is wrong.
I changed the cylinder volume like you suggested and retuned the VE table.
So, I can expect the ecm to reference the exact same areas on the Timing tables in SD as it would with the maf connected? That's assuming the maf curve was tuned as well.
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