You would have to measure the voltage on the open circuit and then short the output through your mA meter to calculate it.

 

I’m a bit slow on this stuff (you’d never know I have 3 semesters of EE before changing degrees)

can you expand on this? I opened my board again and verified it isn’t laid out at all like a ms3 so I can’t follow that hw manual.

I drove the car again today and had the failure at almost exactly the same rpm.

 

I reread your post and understood it. Confirmed there is a 5v pull-up on the crank sensor via testing. I’m going to play with different settings now to see if I can resolve this.

 

For those playing along, I mean the output would could read 5 volts. Put your meter on amps and you might read 0.005 amps. That would be a 1000 ohm pull up resistor because 5 / 0.005 = 1000

 

Thanks for the info.

fwiw I did composite lots of both rising and falling edge triggers. Rising edge was worse and also suffered timing drift. I went back to falling edge. Issue is not resolved. I feel real stuck….

 

Omg I hate myself. Noise filtering was the issue. I turned it on while trying to test VVT settings and the filtering was too significant at high rpm’s and masked real teeth!!

solved. Now to fix my throttle plate sticking slightly open.

 

fun update on mine... I have been having tons of issues because I had a problem with cam signal wire. It must have an internal break, I ended up splicing a temp wire directly to the ecu and bam I have a signal! now I'm going to work on the rest of it, but very glad to be past that hurdle.

 

How is everyone else doing on their setup? I think I’m going to move away from megasquirt this winter. I’m still struggling with loss of sync. I’ve added a better ground, built an external filtering circuit which pulls the sensor up to 12v and uses an opto-isolator and Schmitt trigger to pre-filter the crank signal.

While that circuit helped a lot, I’m still having one or two loss sync episodes during a 30 min drive. the circuit isn’t great, because it’s essentially just redoing the internal megasquirt circuit which is known to have issues on high tooth count. It isn’t fast enough.

I think being that this is a MS3Basic from rev I can’t switch to using the VR circuit design with adjustable POTs.

I’d probably be willing to live with a loss of sync every now again, except the car won’t resync without a power reset. I suspect this is because my trigger offset is 396 aka a full rev off and I bet the firmware can’t handle that. Just a guess.

so unless I can have a foolproof solution to this problem I’ll likely switch to haltech…

 

Took the car to autocross this weekend and had zero issues.

 

Awesome news! Sent you a PM, I would really appreciate your help. Thanks!

 

Necro bump. Thanks for this, anything else needed?

 

Not really. The k24z3/z7 is 60 tooth tho so don’t follow the 12t comment

I ended up always having sync issues so I eventually upgraded to haltech and never looked back.

if you want my ms3 tune send me a pm. It was rough but worked.