The Megasquirt software guys rewrote the engine timing decoder for the 4200 last year, I recently had time to convert over to the GM crank and cam sensors.

End result - the engine starts and runs smoother than it ever did.

The last item I need to set up and get dialed in on it, is the VVT exhaust cam control - others have already got it running - just on stock engines (using MS3 or MS- Pro) so I know it'll work.

So for anyone wanting to ditch the stock GM ecm and have 100% control over the engine - MS3/MS-Pro will do it. The only change is to run the '08/09 crank sensor. It's a direct bolt in - minor connector and wiring change.

The aftermarket HPtuners and EFI-live GM ecm tuning software don't expose the VVT tuning parameters.

Last edited by efi-diy; 07/24/16 03:06 PM.

51 GMC 4.2 turbo
Can't solved today's problems using the same technology/thinking that created them