Ignitor trigger signal issues

[vrtigo]

Hi guys,

Have had my MS running on my 4AGE with distributor for about 3 months, pretty solid! Yesterday I drove the car to the shop and back, no problems. Today I try to start, no spark. After checking fuses and wiring, I swapped out for the factory ECU, and it fired right up. Im using a harvested ECU connector which Ive soldered wires to the back of. I then tried measuring the cycle rate of the trigger line at the ECU connector with my multimeter - got a solid 12.3hz, which equates to around 360rpm, spot on. So the signal seems to be firing ok. At first I thought the ignitor transistor had fried. Could it not be passing the right voltage/current to trigger the ignitor? I dont have a scope to check with unfortunately, and its difficult to judge a square waves voltage with a MM.

No data log, youll just have to trust me that Im getting rpm. Its an MS1 with v2.2 board, using the distributor settings. Must stress that its been working fine for 3 months now, and nothing has changed. Im leaning towards the ignitor driver has probably popped. What does this sound like to everyone else?

[Matt Cramer]

Does TunerStudio see RPM while cranking? Does the output LED pulse off and on?

[vrtigo]

youll just have to trust me that Im getting rpm.

Yes.

And yes, the LED is flickering when I disconnect the ignition wire and set to inverted.

[Matt Cramer]

[vrtigo]

What else could you possibly need to know? Set up using MSnS Distributor mode, it was working fine, suddenly not. Ive given you the symptoms. Its purely a hardware problem. Guessing is what I want you to do. Take a stab and suggest some avenues that I could pursue based on the information provided.

[vrtigo]

FYI this did turn out to be a popped ignition output transistor. Had it blow a few times after this, until I decided to put a diode inline after it in the loom - no more problems.