MS3 and LT1 Camaro

Testing and development of Megasquirt 3

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jsmcortina
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Re: MS3 and LT1 Camaro

Post by jsmcortina »

Dookie454 wrote:I scope high and low opti signals, with and without spark... All ok. No difference.

Scope of low res and tach/coil output looks fine without spark powered up... Once spark is on, the low res is fine, but tach/coil drops out, kinda jumps all over when sync loss.
Thinking back to basics here.
The firmware doesn't know if you have a coil connected or not. The output is just the same and there is no monitoring.
So, it seems, the only way that hooking up the coil can be causing a problem is interference with the signals getting to the Megasquirt (or even inside the Megasquirt.)

I'll see if I can think of a way of making the sync-loss reporting more informative so we can track down exactly what the firmware doesn't like about the input signal.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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Dookie454
Experienced MS/Extra'er
Posts: 344
Joined: Mon Jul 25, 2011 9:18 pm

Re: MS3 and LT1 Camaro

Post by Dookie454 »

jsmcortina wrote:
Dookie454 wrote:I scope high and low opti signals, with and without spark... All ok. No difference.

Scope of low res and tach/coil output looks fine without spark powered up... Once spark is on, the low res is fine, but tach/coil drops out, kinda jumps all over when sync loss.
So, it seems, the only way that hooking up the coil can be causing a problem is interference with the signals getting to the Megasquirt (or even inside the Megasquirt.)
Agreed. I also have isolated everything possible, including not even using the Tacho Pin 26 output at all, and as long as there is spark occuring (triggered from the stock ECU/Opti), the sync loss occurs.

So to me, it seems the noise is either coming from the air, or from the ground plane. But, the noise is definitely linked to the trigger pattern of the opti wheel since adjusting timing makes it better/worse. With all those 360 slots, I wonder if it's since there's just so many additional points seeing noise that lesser trigger wheels don't see, causing the problem.
MS3X on 2010 Camaro LS3 + Whipple @ 10psi + HPT + AEM 30-0333/0334 WB
MS3 Knock Module + JBPerf Dual VR v2.1 (Removed), didnt play well with LS3 DBW Motor, works for VSS.
OLD: 1997 Chevy Z71 Vortec 350, + BOSCH 0261231036 WB Knock Sensor
OLD: LT1 TA 700hp + MS3X
Dookie454
Experienced MS/Extra'er
Posts: 344
Joined: Mon Jul 25, 2011 9:18 pm

Re: MS3 and LT1 Camaro

Post by Dookie454 »

Tonight I decided to drive an electric cooling fan by the MS3 Injector 2 PWM output.

It worked fine.

I ran the Opti Spark with 0 Fan/PWM output, and all is ok.

I ran the Opti Spark with any bit of PWM output, and sync loss shoots through the roof.

Does something like PWM fan or Meth pumps cause sync loss with other triggers, or just the 360 degree wheel Opti?

Hey James, is there any other way to get a sequential signal from an Opti, perhaps without the 360 wheel? Im ok if it has to crank longer before starting, or something similar. What if I was to modify the 360 wheel by removing some slots to make it less sensitive?
MS3X on 2010 Camaro LS3 + Whipple @ 10psi + HPT + AEM 30-0333/0334 WB
MS3 Knock Module + JBPerf Dual VR v2.1 (Removed), didnt play well with LS3 DBW Motor, works for VSS.
OLD: 1997 Chevy Z71 Vortec 350, + BOSCH 0261231036 WB Knock Sensor
OLD: LT1 TA 700hp + MS3X
shortbus
Experienced MS/Extra'er
Posts: 175
Joined: Wed Jun 02, 2010 6:43 am

Re: MS3 and LT1 Camaro

Post by shortbus »

For the LS coils -- Where do I get the switched 12v? Any suggestions?
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