Megasquirt Weird voltage issue from fan output
07-18-14, 07:22 AM
#1
Weird voltage issue from fan output
I am having a weird issue where I am getting voltage back through my JS11 output (Fan relay). With the MS powered off and the fan output connected at the relay, my LEDs on the MS stay dimly lit. If I unplug the relay it goes away. I tried changing relays hoping this was the problem but made no difference. I have a flyback diode (1N4933) soldered between the negative (fan output) and positive side of the coil, with banded end at positive side.
The fan output circuit is using the built in output circuit for the Zeal card. JS11 is jumpered to Zeal IN1, Zeal OUT1 is jumpered to SPR3.
FWIW, I can test the output on the stim' and it seems to work fine, but I don't really have a way to power the relay but not the MS from a bench. I would use 12V on the stim' to energize the relay coil. No stim' power means no power for either so I can see if the problem persists.
Any ideas what could be causing this?
*On a good note, I've finished wiring the car. I was able to spin the CAS by hand and see the spark plugs fire!
The fan output circuit is using the built in output circuit for the Zeal card. JS11 is jumpered to Zeal IN1, Zeal OUT1 is jumpered to SPR3.
FWIW, I can test the output on the stim' and it seems to work fine, but I don't really have a way to power the relay but not the MS from a bench. I would use 12V on the stim' to energize the relay coil. No stim' power means no power for either so I can see if the problem persists.
Any ideas what could be causing this?
*On a good note, I've finished wiring the car. I was able to spin the CAS by hand and see the spark plugs fire!
07-19-14, 10:13 AM
#2
Engine, Not Motor
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Did you follow the wiring diagram on my website? I admit, there is a mistake in that diagram which I had intended to fix when I made the big update but it slipped my mind.
My diagram shows the coil powered from constant 12V. It should be switched 12V. If powered by constant 12V, a small amount of power will feed back into the MS. Removing the relay removes the path to 12V via the coil and thus stops this.
My diagram shows the coil powered from constant 12V. It should be switched 12V. If powered by constant 12V, a small amount of power will feed back into the MS. Removing the relay removes the path to 12V via the coil and thus stops this.
07-19-14, 04:20 PM
#4
Major update:
All my outputs to simplify starting the car. I was able to get a couple pops of combustion from the engine, but ultimately flooded the car bad enough to call it a day. While messing around with some settings and making a few changes to my tune, I lost connection to the MS. I tried all of the usual fixes like rebooting windows, un/replug the USB adapter, ect, but the MS refuses to communicate with TS.
To make matters weirder, the MS seems to be unresponsive altogether. As soon as I power it up, the injectors go static (can be heard clicking on every time the MS is powered) and all 3 LEDs stay dimly lit. I tried reflashing the firmware (on a different PC even) and it can't be detected via COM ports.
I've check the board and can't see any surface components that look scorched, but I am tired and frustrated. Any pointers? I could have started the damn thing today!
Thanks,
Alex
All my outputs to simplify starting the car. I was able to get a couple pops of combustion from the engine, but ultimately flooded the car bad enough to call it a day. While messing around with some settings and making a few changes to my tune, I lost connection to the MS. I tried all of the usual fixes like rebooting windows, un/replug the USB adapter, ect, but the MS refuses to communicate with TS.
To make matters weirder, the MS seems to be unresponsive altogether. As soon as I power it up, the injectors go static (can be heard clicking on every time the MS is powered) and all 3 LEDs stay dimly lit. I tried reflashing the firmware (on a different PC even) and it can't be detected via COM ports.
I've check the board and can't see any surface components that look scorched, but I am tired and frustrated. Any pointers? I could have started the damn thing today!
Thanks,
Alex
07-20-14, 09:51 AM
#5
Engine, Not Motor
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Uh oh. First, remove the processor and perform a serial loopback test as shown in the MegaManual.
If that works, pop on the boot jumper and attempt to reload firmware.
Further troubleshooting will be necessary if you can't get it loaded with firmware.
If that works, pop on the boot jumper and attempt to reload firmware.
Further troubleshooting will be necessary if you can't get it loaded with firmware.
07-20-14, 02:13 PM
#6
I got it to pass the serial loopback test in the MegaManual. I tried reloading firmware 3.2.5 with the boot loader (I'd forgotten loading firmware used to required one), but failed. I got it to flash 3.1.0 somehow and tried connecting to TS again. It worked! I made a few changes to the tune to see if they'd burn (They did) and tried reflashing 3.2.5. After a couple tries it actually flashed. It seems to be okay now. Hopefully the problem was a corrupted firmware from a bad burn. Anyways, off to go try and start the pig!
07-22-14, 03:11 PM
#7
Related to the fan output:
If the 12V coil wire is supposed to be on key-on 12V, would it still be possible to have a toggle switch to the MS?
Currently, I have the MS wired from key-on 12V (still has power during "START") and through a toggle switch. This allows me to easily power cycle the MS for changes that require them and to do things like cold cycle the engine to build oil pressure.
With this setup, I could potentially have 12V at the fan relay coil and no voltage at the MS 12V wire on the DB37. Would the present a problem?
If the 12V coil wire is supposed to be on key-on 12V, would it still be possible to have a toggle switch to the MS?
Currently, I have the MS wired from key-on 12V (still has power during "START") and through a toggle switch. This allows me to easily power cycle the MS for changes that require them and to do things like cold cycle the engine to build oil pressure.
With this setup, I could potentially have 12V at the fan relay coil and no voltage at the MS 12V wire on the DB37. Would the present a problem?
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07-26-14, 11:00 AM
#8
Engine, Not Motor
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The only problem having 12V at the relay coil constantly would cause is a small leakage current and the potential to keep the 'Squirt slightly powered at all times.
If you are going to connect the whole system up to a toggle switch, just put that toggle on the main relay (coil) for your setup which is what would typically be providing the switched 12V for the e-fan relay coil.
Not sure why you'd be cranking the engine to build up oil pressure though. Are you really draining your oil cooler that often?
Oil pressure will be instant the moment the starts and exceeds 500RPM. You may actually cause more wear by much more slowly cranking it with the starter and only developing a few PSI.
If you are going to connect the whole system up to a toggle switch, just put that toggle on the main relay (coil) for your setup which is what would typically be providing the switched 12V for the e-fan relay coil.
Not sure why you'd be cranking the engine to build up oil pressure though. Are you really draining your oil cooler that often?
Oil pressure will be instant the moment the starts and exceeds 500RPM. You may actually cause more wear by much more slowly cranking it with the starter and only developing a few PSI.
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