SilentStorm

Hello Everyone,

I am hoping some of you can help me debug my issues with my 97 Miata with a VVT swap. My dad and I have just finished putting in the VVT engine which we know as running before we put it in from the previous owner. We followed the https://www.miataturbo.net/engine-pe...athread-80469/ overall to get everything running. As far as we are aware the physical components are all correctly installed. As a note, this does have a port and polished head with bigger valves and stronger springs. As far as the wiring, we have done a lot of independent tests with the voltmeter and oscilloscope of the different wires, tracing and comparing to what the documentation said. We did encounter issues with the crank sensor and getting a tooth log at first, we had to put a pulldown resistor on to get the voltage across the 3v mark for the computer to register. After this we are able to track the teeth shown here: https://97miatatroubleshooting.s3.am...8_20.21.09.csv. We are clearly still encountering lots of sync errors code 38, which from what I looked up is basically the 4G63 sync loss. The composite log https://97miatatroubleshooting.s3.am...8_21.35.14.csv is here. The

The tune started with the base tune sent with my megasquirt ms3pro pnp: https://97miatatroubleshooting.s3.am..._Miata_150.msq. We made a few changes as we were having issues around the cranking startup, which made no difference: https://97miatatroubleshooting.s3.am...urrentTune.msq. Here is a large data log pulled while trying to start the car multiple different times, https://97miatatroubleshooting.s3.am...8_21.05.59.mlg, there is a good example of the startup around 1663s. We know we are having some battery issues and had to switch batteries and hook up chargers, especially since we keep trying to crank.

Any guidance on what to look for, try, or do next would be greatly appreciated.

Thank you,
Adam

natewin

Not getting anything from the download links.

SilentStorm

Thank you for pointing out that this was wrong @natewin . I have updated these links and think they are working now

natewin

You are mentioning 4G63 and it is in your CurrentTune.msq
Have you ditched the CAS and run the front NB crank trigger and the CAM sensor now?
4G63 is for CAS cars. You should need to pick Miata 99-05 in the Ignition Settings >> Spark Mode
I'd also just use all the settings from a 01-05 tune in that section, since the other options change when going from CAS to separate sensors. You are also running the NB COP I would think.
This should put your trigger and cam sensor to work properly.
Did you run the car on this tune previously, only difference is now VVT motor?

Did you keep the NB throttle body? If so you will need to change your idle settings.




01-05 ignition settings, basemap.

SilentStorm

Hey @natewin ,

Thank you for the quick response and assistance. What you are saying does make a lot of sense switching over the spark mode.

This car was stock when I got it with a broken keyway. My dad an I tried repairing it, but the previous owner hand neglected the issue to much and it was beyond repair. We had it limping along until we found this VVT motor with low miles to do a swap. I was having issue with the Crank sensor as I think it was broken due to being hit by the wobbling pully and trigger wheel. I did get the stock NA car and motor running on the megasquirt prior to making the VVT Swap.

Yes we did get rid of the NA CAS and now have an independent CAM sensor and Crank sensor, wired back into the original CAS wired per the "Definative VVT Swap Guide." I will definately follow your example screenshot, so thank you very much. We are running the NB COP as the NA coil packs don't fit with the VVT piping.

As far as the throttle body, to make a little changes as possible, we currently have the original NA throttle body on there. Will this cause us any issues? or are you just saying if we switch we need to change idle settings?

Thank you again for you quick response and help. We are planning on working on this tonight and will give your suggestion a try.

Thank you,
Adam

natewin

Sounds like you are on a good path for now. FYI I don't have much as far as VVT actuation advice, will be doing that over the winter.
The NA throttle body will work fine, use the 97 basemap settings for that if you like. Many people here end up using the NB throttle body b/c it has internal bypass for the IAC, you won't need that 2nd hose for your intake. This makes boost much easier.
Stay on course to get the motor running with as few changes as possibly, like you are doing. If you want to go to NB throttle body it is pretty easy, change the IAC and TPS connectors and you are good to go with a few tune changes.
Basically use 97 basemap for everything other than VVT and ignition settings.
You should take a look in the basemap for 01-05 and use the Ignition Table and Fuel VE Table from those. I'd open the 01-05 basemap in TS, open the ign/fuel tables and the green up/down arrows in those tables to export from 05 and import into 97.

SilentStorm

Hello @natewin ,

Thank you so much for all of the help yesterday. After configuring the ignition settings like in your photo the car started right up and idled. Still need to go get the 01-05 tune and compare the fuel tables. Next thing we need to look into is the fact that we might have a vacuum leak or something during idle we were not going under 45KPA.

Thank you again for all your help,
Adam