programming 101 and checksum

[Bruce Plecan]

-----Original Message-----
From: goflo at pacbell.net <goflo at pacbell.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Monday, August 10, 1998 4:52 PM
Subject: Re: programming 101 and checksum


>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? 

-40dC to 100dC    100,700ohms at -40, to 185 ohms at 100dC
>                  
>                  Is tempco positive or negative? 
>                  IOW, does resistance go up or down 
>                  as temp goes up? 

Resistance goes down as temp goes up
>                  
>                  What voltage does the ECU apply to 
>                  the sensor? (Disconnect the sensor 
>                  and measure across the ECU terminals.)

5v
>
>Coolant temp:     Likewise.

Exactly the same as Intake air
>
>MAP:              0-5V, 1 bar is 5V approx. Correct?

Engine off 4.9ish, idle like 2+, WOT slightly less than key on engine off
>
>TPS:              0-5V, throttle closed to WOT. Yes?

In general .5v at idle, 4.8 WOT fine.
>
>Dist. ref pulse:  How many pulses per rev? 

v-8, 4   v-6, 3

>                  Amplitude? (5V?) 

I've been using the voltage drop across a LED to the module as
the rpm signal.

>                  When does it occur? (TDC?) 

Base timing varies per application, 0-10d BTDC
>
>4th gear switch:  Is it a switch? 

Yes

>                  How many wires go to it?      

One grounded when applied.
>
>neutral/park sw:  Ditto.

One wire, grounded in gear.
>
>VSS:              What is it?

Vehicle Speed Sensor,  2000 pulses per mile.  12V
>
>TCC:              What is it?  

Torque Converter Clutch,  ecm grounds a solenoid to apply.
>
>O2 sensor:        Conventional O2 sensors put out 0-1 V. Is this
>                  the input to the ECU? 

Yes
>
>What is the max rate of change of engine rpm?

600-6000 rpm in 2 sec.s in first gear.
>
>What kind of PC do you have?

IBM Comp.   Windoze 98. 
>
>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.

Very Kewl, no problems here
Cheers
Bruce
>
>Regards, Jack
>
>