Turbo Miata & ODB2
 

Howdy,
I own a 97 Miata with a FM Voodoo 2 turbo kit (gt2560r/stock motor). Car is running 12 PSI on 320cc injectors with a voodoo and an msd tuning box, 8 degrees BDTC static timing a yonaka (comma bro) catback and a test pipe. It wasn't my choice to go odb2 but I happened to trade it for my e30.
The car runs pretty well, idles smoothly and the AFRs go nicely to around 10-1 @ 12 PSI but the car will eventually throw a code for bank 1 mixture :jerkit: and one for lack of a catalytic convertor.

I have a year to get this thing inspected, which means having the car set ODB2 readiness. As much as I understand going megasquirt cures cancer, it just won't work in my application at the moment. I may decide one day to swap back and forth with MS only for inspection time. Considering I live in an urban apartment, swapping the drivetrain in an ODB1 shell is out of the question.

As I see it I have two possible options:

1. Run 305cc injectors, from searching the forums these seem to be within tolerance for the dme to adapt to but will they handle the 12 PSI or will I have to back down? What can these typically run?

2. Pick up an AFPR and dial down the fuel pressure ever so slightly to where the amount of fuel is within the DME's adaptability for a week before inspection. Stay out of high boost, let the car set readiness, turn it back up, profit.

3. Move to south carolina and forget having a full set of teeth because no ODB2 inspection?

I forgot to mention I've already picked up a magnaflow 2 1/4" high flow cat, but don't want to install it before my fueling issue is sorted as I'm afraid I'll brick it prematurely.

https://www.miataturbo.net/attachmen...ine=1452486822

Thanks in advance!
Julien

You are using a piggyback system designed for 8psi, then trying to run 12psi. Stop doing this and all your problems will go away.

Agree'd with the above. Run the 8 pounds the VooDoo box is meant for. Want more? Get an MS.

"Tune" the car with what you have already installed, then install your cat. Preferably, in a fashion to which you can swap in that test pipe, after the inspection period. The reason? A turbo car running on a VooDoo box will never run clean enough to make that cat last, and it will likely get nuked in a few thousand miles at best. Might as well "save it" to use next year when you get to do this all over again.

Also, use whatever injector the VooDoo box is designed for. Anything of a different size will just be another variable to chase down. And leave the fuel pressure alone.

Since you don't plan on running Megasquirt, put stock njectors in and turn the boost down to 7psi. Enjoy getting no codes.

Thanks for the feedback y'all. I guess I'll get a mbc to turn ze boost down when I swap injectors. About megasquirt, id consider it if I could make it an easy 1-2 hour swap process. I guess I could always tie the waste gate open, run oe injectors and run sans voodoo box and msd box for inspection time

You don't need to buy any boost controller. Simply return the FM II kit to the way it is shipped to you, in the box. Use with stock injectors, and VooDoo box.
Drive the car a 100 miles or so until all the readiness monitors are satisfied. Don't take trips to redline, don't load the engine heavily, don't drive like an ass, and you will have a successful outcome at the emissions test.

Does it have anything now for boost control? If not, you need a lower wastegate. Boost controllers only can raise boost.

Afaik the way the kit is initially installed is with spacers on the waste gate to limit boost. I figured putting an mbc in line would be quicker/easier.


*shrig*

Spacers on the wastegate? Where? MBC will only raise boost.

" Medium (GT2560R) and small (G2554R) Turbos Only: Add a washer underneath each bolt holding the wastegate actuator to the bracket (in the picture they’re not increasing the boost (1)). The washer will need to be placed between the actuator and the bracket. Add one washer (to each side) at a time, until you achieve your target boost."

I guess I'll start playing around with it.

It sounds like they are using washers to increase actuator preload. Remove them and see if that doesn't drop the pressure.