In SX Microcontrollers, SX/B Compiler and SX-Key Tool, markistuff wrote:

I did some reading and i think i figured out why its backfireing, ill test it out later today to see if it fixes the problem.

william chan -  yes the nic4422 is directly driveing the injectors.  not till you pointed itout did i realize they are fore driving the mosfets, miss read the data sheet, put they are supost to handle 9 peak amps and about 2 hold amps, thats plenty for driving ingectors and ignition so i think ill be ok running that.  the reson why i picked them is they were some of the first that showed up in the parts search and they could run off logic level and handle a fair amount of current.  

John bond - you asked if its possable to get the pulsewidth from monitoring only the throttle, RPM, temp and O2.  yes you can, but it wont be near as good as haveing a map sensor to detect the manifold abu(expletive)e pressure.  with out a map or maf, it will inject a pre determind amount according to throttle and rpm, but it dosnt account for engine load and altitude.  so the o2 sensor will work away to correct the ratio( a narrow band O2 sensor only works a low rpm.  thats the problem i think i had, at high rpm my engine leans out and back fires)  so for sudden changes in opporating conditions it wount work as good.  but detecting the air comming into the engine gives a pretty good indication of whats going on therefor it can adjust the pulswidth accordingly.  well as far as i understand. 

  if i were to add sensors it would be a humittity sensor.  it would help out in calcuatling air comming into the engine. thats probably about it

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