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I noticed that when the temperature is cool and the air is thicker my BLMs go up, and when the temperature is hot and the air is thinner my BLMs go down. The reason why is obvious. My question is if there is an adjustment somewhere that allows me to correct this or is it simply normal on this minimal system? I thought perhaps the MAP would automatically compensate for the density changes but it does not appear to completely do this.
Thanks
Roy
The MAP sensor only measures air pressure. It can not measure air temperature. The air temperature also changes the air density. (Remember PV=NrT?) The MAP sensor only knows pressure (as compared to a known quantity.)
You COULD argue that the small amount of air in the MAP sensor cell is also subject to the same temperature changes, but once it heats up under the hood, that comparison is lost.
If your numbers are within 10% of 128, I think you're in pretty good shape, IMHO.
The TBI car computers (Caprice, Camaro) had air temperature sensors. I've also noticed BLM changes with weather changes. The "Learn" of the 7747 will adjust for weather changes to a minor amount.
dave w
Don't think so, it would need IAT or MAT...