I took the MS2 board, connected it to the car and burnt out two primary injectors. We traced the problem to a broken R20 factory installed resistor. I returned the board for a resistor replacement, checked the board after it was returned on STIM, and found that the injector 2 circuit was still shortened. Not happy. DYI Autotune sent a replacement board, the injector issue was resolved and swapped with the new board, swapped the zeal daugthercard with the old board. On energizing, the fuel pump starts for 2 seconds, but I have no tac, no spark, and no injectors. PCB 3.57 VR circuit has 2.5 volts to CAS but VR2 from zeal daughter card has 0 volts from CAS and no output. I suspect that this might be a damaged zeal daugthercard card but I don't know what component to replace. I have proven that the zeal daughtercard has both 5 and 12 volts supplies energized to the card. Any thoughts on what to do? Help is greatly appreciated.

 

I had a little time last night and used the STIM on the Board to test if the VR2 was seeing voltage and it was 5 v. I then touched Pin 3 on the LM1815 with my Volt Meter and ttteh Led's started to blink along with the STIM fuel pump light. Tuner studio also showed injector pluse width, the RPM Pot now worked on the STIM and Ignition advance was showing a reading as well.

I am going to guess that the LM1815 is bad on the board. Just touching pin 3 with anything causes the above to happen. It appears that adding capacitance to pin 3 lights it off.

Any comments most welcome.

Ark1

 

I'm confused by the statement "PCB 3.57 VR circuit has 2.5 volts to CAS ". What are you measuring from where to where? While spinning the CAS?

Same with "VR2 from zeal daughter card has 0 volts from CAS and no output". What exactly are you measuring?

Checking the CAS circuit with just a voltmeter isn't going to be very helpful. You really need a scope to trace the signal.

I can't find the schematic to the Zeal so I don't know if it has a capacitor on pin 3. Looking at the typical MS implimentation, a 330pF cap is used. Pin 3 is input to the chip, so you may simply be "stimulating" it with your meter.

 

Thanks for getting back to me Aaron. In response I did check the Zeal not turning and found zero volts apposed to the VR circuit on the 3.57 board with about 3 volts not turning. I did put a dual trace scope on the CAS and Proved both 24 tooth signal and Camshaft signal. So the VR board is not at fault here. CAS is good too.

I swapped out the Zeal card on to another 3.57 board and D 15 flashed when cranking and I now have trailing spark. D14 and 16 did not blink. At the direction of Matt Crammer I installed 1k resistors from pins, 7, 8 &9 on U1 to Pads 1, 2 & 3. ( not in that order)

This has D14, D15 & D 16 blinking along with trailing spark. Leading is not sparking.

Reading on the internet about the leading coil I applied 12 volts to the tan wire of the Leading coil and 4.5 volts to the Red trigger lead. I grounded the trigger lead hoping to see a spark, but none was seen. I suspect the leading coil ignitor as I removed the leads from the secondary winding and spashed 12 volts across the terminal and obtained a spark at the connected spark plug.

I have on order a used Leading coil but it will be over a week before it comes in. If there is another way to prove a leading coil on the FC ignition system please let me know. If there is something I am missing be blunt and tell me.

If the new leading coil does not work I will abandon the ignition portion of this Megasquirt upgrade and install the FB ignition system and use Megasquirt for Fuel only on this FC swap.

Ark1.

 

That's the way I generally test the coils, except I trigger them with two AA batteries in series. Same difference.

The ignitors are easy to damage with excessive dwell or an inverted signal. Both ofthese can happen if you are flashing firmware with the coils connected.