29y3 Iddle valve PWM at cranking

[ukaniu]

Hello,
I have simply Bosch 2 wire iddle air valve from KE-Jetronic.
Everything is working ok but i cannot get PWM signal during cranking. Valve is fully opened (duty cycle 100%) no matter what is written in Cranking (dc).
When ECU is driven into normal operation (above 300RPM) i have good PWM signal at valve, varying from temperature or closed loop.
Code is MS1EXTRA 29y3
Is it normal?
(throttle closed, no anti flood etc.)
Thank you for answering.
Cheers from Poland.

[Matt Cramer]

[ukaniu]

Hello Mat,
In configuration file there is nothing special. I put new default configuration in uC with minor changes considering idle and engine constants.
Please look at the datalog - when IDLE DC is 60% there is no PWM output signal (I tested 20, 60, 80, no change). When IDLE DC becomes 24% there is output signal driving output stage. So datalog look imho OK but scope tells something else.

[Matt Cramer]

The data log shows it doing what's expected: Using the cranking DC at startup and the regular duty cycle when running.

[ukaniu]

Datalog is ok but i have no electrical PWM signal while cranking - only 100% full battery voltage no switching. PWM signal apear after cranking state and then i see 24% PWM or what else is set, but there is no 60% or any other value present at output pin when ecu is in cranking state.