ecu voltage problem

[Sandy]

At 09:29 AM 5/1/97 -0700, you wrote:
>At 08:13 PM 4/30/97 -0700, you wrote:
>>When we hook up the 6V radio shack supply we connect it directly to the
>>ground and power lines on the board, thereby bypassing the Voltage
>>regulator altogether. However the board has worked on an engine mounted on
>>the stand using the voltage regulator and the 12 volt batteries.  
>>
>>I always thought 1 ms was awfully slow as well but the engine actually
>>idles with the 1ms event times at the injectors, very lean I suspect, but
>>running none the less.  The MCU is putting the 1 ms pulses on the pins of
>>the 1949's but the 1949's don't even get to hold state with that little
>>time.  
>
>1ms may be too short to see the effects of the hold state. I can't remeber
>off hand what it looked like on the scope when I tried it with low
>impedance injectors (~2ohm). You can also see what the feedback voltage is
>doing by looking on the sense pin of the lm1949, if it is not getting to
>385mv, then it won't trip to the hold state. Check the Lm1949 data sheet.
>
OOPs, it will trip to the hold state IF the timer function is used, again
see the data sheet.

Sandy