I was testing idle-channel output using two different channels with my scope.
- Using Step A push-pull output: was always on (0% TSP of course) even before I started trigger-signal
- this can be normal, depending on your setup. Config determines behaviour, which might be according to intent
- Using SPECFET1 I never got any output (selected in MT), and it is mounted. Beware that flyback diode is needed for specfet when driving inductive load like a solenoid!
- To measure a "low-side" output (that can only pull to GND5, cannot pull towards +supply) with respect to GND (DVM or scope) you need a pullup resistor (100 Ohm .. 10k is OK for this; if you only have 22 Ohm at hand that's OK too, but don't let it run for more than 1..2 secs at 12..14V because it will overheat and burn).
- measuring with DVM from 5V or +supply might or might not work without a pullup resistor. The reason is that a typical DVM acts as a 10 MOhm (very weak! 1000 times weaker than 10k)pullup when other probe connected to +supply.
- I did use a pullup resistor (around 5k) from +12V, I probably just did some think wrong when testing. I'm not using this channel fore Idle anyway, and the "test-setup" is now taken down and the box is in the car, so it's not so easy to debug on.
Connect a diode (like 1n4007 or BY399 or ES2J or similar)
- anode to switched point of the solenoid (channel output, EC18-pin..)
- cathode (marked with a line) to the other pad of the solenoid: the same where you connect the positive +12V (switched and fused) power
Q: What output channel is recommend fore idle-valve (2-pin VDO-valve)?
- a free injector channel is most common
- or a stepper output
- Okay I'll just stik to the stepper-output, mount a injector-fet next time the box is out.. thanks
I finaly got time to work on idle.. and it works!! :)
I just got a question about some settings:
- "iac_conf RAW" under Idle setting in MegaTune
- it's the "packed" value of several IAC related flags: (from global.h or varstr.h / magicstr.h):
- uint8_t iac_conf; // iac, bit7:softidle bit6:asym bit5:dualsol bit4=1:ignadv ON, bit3:preciseidle bit 2:stepper(0=pwm) bit1:low_power_halt bit0:power_iac_only_when_move
- when you're on the phone, it's much easier to instruct someone to read (or set to a particular value) this value than list all the options.
- iac_conf=18 (decimal 24), which means bit4 and bit3 are set: ignadv based advance is ON; preciseidle is ON (but not stepper, so PWM-solenoid)
- And how does "IAC afterstart, step per 160rpm" work?
- iac_afterstart_step was a hint to the ECM of how much added opening is required. Use very low value, 1 or 0. It's ripped from recent firmwares. What firmware do you use ? v.13 or so..
- value of 4 means: If you configure +200 "afterstart" RPM, +5 (=4 * 200/160) will be added to the iac reference position. 0 is reasonable, the PID integral (I-term) should have no problem reaching the higher RPM.