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Discussion and questions related to the course MoTeC M1 Software Tutorial
Hi, looking for the correct way to setup a 3 wire IACV (Bosch 0 280 140 505) with an M130 please. I have limited knowledge of the half bridge setup so far and it appears 12+ should go to the middle pin, what about the outer two pins? I attached an old Motec doc showing the Idle valve assignments but it does not apply to an M1
Based on the vendor firmware & the provided wiring harness here is the three wires/pin locations as currently wired.
A_31 = Half bridge out 3, and bridge out 2 negative.
A_32 = Half bridge out 4, and bridge out 2 positive.
A_33 = Half bridge out 5, and bridge out 3 Negative.
A_31 goes to IACV pin #3
A_32 goes to IACV pin #1
A-33 goes to IACV middle pin #2
I read that an “Inverting Resource” must be set up in the package coding.
The datasheet you have attached details using this idle actuator solenoid on an M8 which is an older MoTeC ECU, pre-hundred series.
You can use this solenoid with an M1, this would be done by using HB3 and HB4 as the normal and inverting output resources respectively. The centre pin of the idle actuator solenoid should be wired to 12V+ ignition power as stated in the datasheet.
It's important to note that the recirculation diodes in the datasheet diagram will not be required when using this solenoid with an M1 as the bridge circuits have recirc diodes onboard.
Regarding your specific firmware and wiring configuration you may need to contact the supplier for more specific information. Which firmware package are you using?
From looking at the information that i can find on that unit, it's a three wire stepper motor. I have attached the M1 Idle Stepper Motor setup documentation. Just treat this ICV as half of a 6 wire motor.
Hi Scott, thank you for the reply. Very helpful information. The way they have it wired at this point, the center pin on the IACV comes from ECU pin A33 (HB5) and appears to be getting 12V+ with ignition on as is, do you think it is fine to leave it that way?
With your use of HB3 as the normal output resource and HB4 as inverting - when looking at the old data sheet which one would be "pin A (slave)" vs "pin C (control)" on the IACV ??
Posting here because I am having difficulty receiving info/reply from the supplier, but the firmware is a TPS/alpha n setup by Rasant for an air-cooled Porsche flat 6.
Thank you Stephen & Scott. Adding additional information - screen prints from the firmware wiring page and the idle setup page for additional help. Just realized they have the HB4 is in use for the plenum flap valve so not sure. M1 is only allowing options for inverting output as either HB5 or HB5 ??
The Half bridges are not designed to be used as constant power supplies, so it is better to wire the power supply for the valve to a switched battery source.
They have configured that valve as a solenoid valve, these typically have VBatt on one pin, and are pulled to ground by the ECU to control them. Varying the pulse width applied to the valve changes the amount of air bypassed through the valve, they work in the same manner as a boost control valve, just with a higher mass flow capacity.
The valve that you have described as being fitted on your car sounds like it is a stepper type valve, where the motor is supplied a constant VBatt and the ECU pulls either side of the valve to ground, depending on the the direction that the valve needs to travel in. With a stepper valve, you wire them to a Bridge (two paired Half Bridges i.e. HB1 and HB2 make Bridge 1 with the uneven numbered HB the motor negative) and a common power supply.
Hi Stephen, really appreciate the useful info. I read the Motec doc you sent about stepper motors. Based on that description a motor is "stepped" through its range of movement and rests in the last position, there is no spring return. Attached photos of the valve.
I pulled the unit and did a simple bench test with a 9V battery, positive V to the middle post. It definitely acts like a normal idle solenoid and does have a return spring. Its' normal resting position is about a 10% open slit. If you supply the negative to pin 1 the valve fully closes. If you supply the negative to pin 3 the valve fully opens.
The problem we are seeing with the current configuration is that when fully warm it will often stay at a high idle. Acting like the valve is not being pulled closed enough possibly. When experiencing the high idle you hear a loud hissing vacuum from the IACV. Then if you temporarily unplug the IACV and plug it back in the engine returns to proper idle and the vacuum noise is gone.