programming 101 and checksum

[goflo at pacbell.net]

Bruce Plecan wrote:

> The inputs are, intake air temp, coolant emp, MAP, TPS, distributor
> reference pulse, tranny 4th gear, park neutral switch, vss signal.
> 
> The coolant temp/intake air temp are easy.
> 
> Having something that reacts to TPS is another matter.
>   MAP is high, engine off, and then drops at engine run.
>   MAP varies with little with TPS,
>   High rpm, MAP is almost atmospheric like at start up.
> 
> At 40 mph low tps have a 4th gear engaged signal, so ecm can
>   apply TCC.
> 
> Would be nice to introduce an engine miss option at idle to see
> what the ecm does about it.
> 
> Having O2 feedback would be a nice option.  Sudden change in
> pulse width high O2.

**********************************************************************

Intake air temp:  What is the range of the sensor? 
                  
                  Is tempco positive or negative? 
                  IOW, does resistance go up or down 
                  as temp goes up? 
                  
                  What voltage does the ECU apply to 
                  the sensor? (Disconnect the sensor 
                  and measure across the ECU terminals.)

Coolant temp:     Likewise.

MAP:              0-5V, 1 bar is 5V approx. Correct?

TPS:              0-5V, throttle closed to WOT. Yes?

Dist. ref pulse:  How many pulses per rev? 
                  Amplitude? (5V?) 
                  When does it occur? (TDC?) 

4th gear switch:  Is it a switch? 
                  How many wires go to it?      

neutral/park sw:  Ditto.

VSS:              What is it?

TCC:              What is it?  

O2 sensor:        Conventional O2 sensors put out 0-1 V. Is this
                  the input to the ECU? 

What is the max rate of change of engine rpm?

What kind of PC do you have?

Hang with me on this. I know its a pain, but I can't read your mind.
This way you get what you want instead of what I think you want.

Regards, Jack