VVT NB in a 94 Chassis
 

Hi all,

I have an MS3 which was originally for a NA 94 turbo engine. Now I've swapped the engine with a 2001 VVT with Fab9tuning COP conversion and a 36-2 trigger wheel. The original CAS wiring wiring was split so the new cam and crank sensors are wired up correctly. I can't get it to fire at all though and getting sync loss 2 error.

Just read https://www.miataturbo.net/megasquir...c-issue-98122/ and I might need to make some changes?

What would I need to change from stock 94 chassis tune to the new setup? I've tried so many settings now from various posts but none seem to help me.

Cranking log and tune attached.

Thanks!

Have you tried using the stock ignition pack/coils just to see if they fire?

I don't have VVT, but I was having similar issues with Fabs COPs. Tested them with MS, and they were sparking in order, but whenever I tried to crank it it would not fire during cranking. Swapped back to the stock ignition setup, and BAM it fires.

They claim its suppose to be a plug and play setup, so technically you shouldn't have to change any settings. But I also tried messing with dwell 3ms and etc to no avail.

However I returned the COPs and got FlowForce's LS coils and those started up fine.

Fab doesn't really support MS

Ah thats not great! I think I just got rid of the Mazda coils a few weeks ago in a garage cleanup!

Has anyone been able to get the Fab9 COP kit working in MS3?

Also, this is the output of that log file attached. It seems the green and blue traces don't line up and the red trace stops after a few milliseconds (sorry, don't know which sensor is which colour).

The crank sensor is 0.010 from the trigger wheel on the feeler gauge and both the cam and crank sensors are brand new. With the original 4 tooth wheel I was getting sync loss 32 also.,

https://cimg9.ibsrv.net/gimg/www.mia...40dc3e6d84.jpg

I spoke to Fab9 and they advised to set to Wasted COP, nominal dwell of 3.2ms and spark duration of 1.2ms.

Do any of these settings look wrong?

https://cimg3.ibsrv.net/gimg/www.mia...b010bd7df.jpeg

Are the coils wired in sequential or in pairs?

Hi Reverant, fab9 say they’re wired in pairs and to use wasted COP.

Had some success with rising and a cranking advance of 10 degrees with -3.8 trigger offset (the NA engine when tuned had -2.0 degrees). It briefly started and sounded like a tractor but has gone back to not starting again.

Does anyone have a MS3 VVT base map so I can try changing the spark advance map?

Have you tried flipping the rising edge and going high to falling edge going low and any variable in between?
My Na vvt swap i believe uses rising edge but it might be going low. i know it ran on some other combo of those but when it did, to get the cam angle offset right required a few negative degrees but running it how I have mine setup now uses exactly 0 offset.

The offset is used to synchronize your mechanical engine with the software in the ECU. All you did by going to a cranking advance of 10 instead of 12 and offset of -3.8 instead of zero was reduce cranking advance by a total of 5.8 degrees. That and the tractor sounding engine when it did fire makes me believe your timing is off. Keep in mind while you're doing all of this, if it's firing the injectors, you also most likely need new plugs.

Well after changing the plugs to new ones and setting the crank timing back to -2.0 it fired up in under a second! I guess instead of replacing more expensive sensors start with the basics!

Thanks!