MSefi.com read only forum (Jan.15,2018)

Help.

I have MS2 with motherboard v3. I built if from a kit. I have been using it successfully for 2 years on my Lemons race car. Recently, I decided to use the FIdle to drive a relay to a circuit that will have flashing lights,, sirens and whatever else it will take to alert my Lemons drivers in the event that the engine is on the verge of overheating. . . but he Fidle isn't working.

I have never used Fidle. I don't know if it ever worked. How the heck do I debug it?

I have the MS hooked to the stim. I have tried disabling the spare ports and configuring the FIdle at a variety of temperature. The Fidle LED never illuminates on the stim. Also, I have checked the voltage from pin 30 and it always reads 3.2 volts. . . regardless of the coolant temp setting. The LED doesn't illuminate and the Port 0 in Tunerstudio (which I believe is FIdle) always says off.

Any suggestions how I might resolve this or go about debugging?

Thank you,
Allen

First, so that others could check your settings, could you post a copy of your MSQ?

I have been on a hiatus for the last few months, but I'm back at it now.

I have attached my msq.

I cannot get the FIDLE or the IACs to work as spare ports. For the IAC, I installed the jumper wire as instructed. I can get the Accel LED to function as a spare port, so I believe I have the software configured correctly.

The fidle wire (pin 30) and IAC wires (pins 25, 27, 29, 31) should be used as ground wires when they are triggered by the spare port conditions, correct?

Check the processor is actually sending a signal to the Fidle driver by probing between R19 input side and ground with a DVM, and altering the Stim CTS pot so TS shows the temp going above and below the set temperature. If it does, the problem is likely the driver. Those pesky ZTX 450 have a habit of dying for no reason. A 2N2222 is a good substitute and seems to be more long lived, and is fine for driving pretty well all automotive relays. If the ZTX has failed, it may also have taken the 2N3904 - I usually just replace them both if a fault is found. They cost pennies.

You have the idle control set to "Solenoid" - this needs to be turned off before you can use FIDLE as an output.

I turned off the "solenoid" setting. No luck. Still won't ground.

Trakkies: what are the drivers that you mention? Which ones are they on the diagram?

For what it's worth, the "port 0" indicator goes on-and-off in tunerstudio. The last time I used the stimulator, I couldn't get the fidle light to illuminate when I thought that it should. I thought it might be an issue with the stimulator, but I am seeing the same behavior with the MS connected to the car.

Any thoughts on next steps to debug?

Under outputs in the schematics section. The Fidle and Pump drivers are identical.

Eureka! Well, sort of. The FIDLE isn't working, but the IAC spare ports are. All I need is 2 spare ports. Now I have them.

I was following Trakkies's words of wisdom. I can see that R19 has voltage when it should and doesn't when it shouldn't, but pin 30 was still no good. I had narrowed down the issue with FIDLE, but why on earth were the IAC ports not working? I looked in the assembly guide, step #22, and realized that I had opted out of the IAC installation step during my assembly since I didn't plan to use an IAC. I followed that step, soldered in the jumper wires to connect the DB37 to the CPU and bingo. . . I have programmable IAC ports!

Thank you to Matt and Trakkies for chiming in and helping point me in the right direction! I still have no FIDLE, but I have spare ports, and that's what I was my main goal all along!

Allen

Ok. I declared victory a little early.

Here's the deal. I'm using IAC1 as my spare port to trigger an electric fan relay. When Megasquirt is powered on, everything works perfectly! As soon as I power off megasquirt, the relay trips and the fan comes on. Turn on Megasquirt, the fan shuts off until the temp / rpm condition is met. Why does the circuit ground when MS is turned off? How do I make it so IAC doesn't go to ground when the power is off?

Also, I can't find a diagram for the IAC circuit.

Help!

Allen

The IAC circuit will be found on the daughter board schematic.

Wire the 12 volt power to the relay so it is turned off on key off.