Quote:
Originally posted by GalantVR41062@Nov 8 2003, 10:25 AM
I was saying the dsm link is a AFC you run threw a laptop to make changes. The stock ecu has the final say, so I think its a big waist of time. It sounds like the problem came out of no where. So injectors it is.
~John
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The DSMLink does not work like an AFC at all. With an AFC you are fooling the ECU by modifying the airflow numbers. With the DSMLink the ECU sees the true airflow numbers and you are changing the fuel inrichment inside the ECU itself. It works closer to a standalone than to an AFC. You don't have the grids like you do in a standalone because that is not how the stock DSM ECUs even handle the fuel.
It is done a little differently in the DSM ECUs than in a standalone or even a lot of ECUs like Hondas where is has specific pressure vs rpm fuel maps. The way the ECU handles idle/part throttle is that it mathmatically calculates what a 14.7:1 airfuel ratio would be based on injector size and airflow from the MAS and spits out that much fuel. It uses the O2 sensor during those times to make adjustments for how far it is off. The amount it is adjusting it are the fuel trims you see in DSM dataloggers. For higher loads it uses fuel enrichment maps to add fuel on top of the calculated values and the O2 sensor is eventually ignored. There are 12 of these fuel enrichment maps in the ECUs. There are also 12 timing maps. A lot of the stuff in the 1G/2G/GVR4 ECUs are the same basic code, but with slightly different enrichment and timing maps. Under WOT with a turbo flowing anything even close to a decent amount of air your going to be working off of the 12th map.