Microsquirt PWM idle valve wiring

sideways242 · 12-30-2020, 02:11 PM

Hey y’all,

So here’s my weird question... When wiring a Volvo 940 Bosch 2-wire IAC to a microsquirt, does one need to include a 1N4001 diode in order to get things to respond in a normal fashion? Ive tried three different IAC’s out of the car and they all respond the same. When using the IAC test mode output in tunerstudio they clatter around and only open from the values 80-95% intermittently...makes tuning WUE on a cold start a real pain. Anyone got any experience with microsquirt and idle valve wiring?

Any input would be awesome, Cheers!

sideways242 · 12-30-2020, 09:26 PM

solution found! Microsquirt requires a diode (1n4001) to be soldered into the two wires with the banded side to the 12 signal wire. The pwm 2 wire valve now works as it should and cold start tuning is possible!

culberro · 12-31-2020, 02:35 AM

Gotta like the "recommended" diode on page 32. I bet this is the reason I could never get the IAC to behave properly.

(no virus)https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAa

linuxman51 · 01-06-2021, 09:18 AM

yeah it needs that. I've gotten them to work without it, but they work a lot better with it.

VB242 · 01-06-2021, 09:32 AM

I gave up and plumbed the k- jet thermo valve in. It doesn't seem to work either though, maybe I need to try another one.

WillettRun? · 01-10-2021, 09:23 AM

1n4001 diode. Freq 100-120, duty about 25min 60 max. Use open loop to find the min/max and then set your closed loop accordingly. Make sure to use idle initial value x CLT and idle spark advance as well to help control surges.

OttoB · 01-10-2021, 03:54 PM

Diode lives easy happy life in connectors rubber boot.

12-30-2020, 02:11 PM	#1
sideways242 Board Member Join Date: Nov 2017 Location: Sacramento	Microsquirt PWM idle valve wiring Hey y’all, So here’s my weird question... When wiring a Volvo 940 Bosch 2-wire IAC to a microsquirt, does one need to include a 1N4001 diode in order to get things to respond in a normal fashion? Ive tried three different IAC’s out of the car and they all respond the same. When using the IAC test mode output in tunerstudio they clatter around and only open from the values 80-95% intermittently...makes tuning WUE on a cold start a real pain. Anyone got any experience with microsquirt and idle valve wiring? Any input would be awesome, Cheers!

01-06-2021, 09:18 AM	#4
linuxman51 BRANDSCHUTZVORSCHRIFTEN! Join Date: Dec 2002 Location: mont, AL	yeah it needs that. I've gotten them to work without it, but they work a lot better with it. __________________ "They bum rushed them in their own crib, they drank all their beer, they partied with their ladies and they left with the trophy" Now with in-house Dyno tuning! Megasquirt Tuning!

01-06-2021, 09:32 AM	#5
VB242 I.M. Weasel Join Date: Sep 2011 Location: Driving the No Malarkey Bus	I gave up and plumbed the k- jet thermo valve in. It doesn't seem to work either though, maybe I need to try another one. __________________ Living life one day at a time. Stopping to smell the oil slick beneath my Volvos.

01-10-2021, 09:23 AM	#6
WillettRun? †John3:16 Join Date: Jan 2009 Location: Fate, Tx	1n4001 diode. Freq 100-120, duty about 25min 60 max. Use open loop to find the min/max and then set your closed loop accordingly. Make sure to use idle initial value x CLT and idle spark advance as well to help control surges. __________________ I still love Jesus and He still loves me. MaxxECU Dealer/Tuner WillettRun Automotive, LLC

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12-30-2020, 09:26 PM	#2
sideways242 Board Member Join Date: Nov 2017 Location: Sacramento	solution found! Microsquirt requires a diode (1n4001) to be soldered into the two wires with the banded side to the 12 signal wire. The pwm 2 wire valve now works as it should and cold start tuning is possible!

01-10-2021, 03:54 PM	#7
OttoB Board Member Join Date: Aug 2006 Location: E(Seattle!Vancouver! San Francisco!LA!) Helsinski	Diode lives easy happy life in connectors rubber boot.