MembersPage/JorgenKarlsson/MiataNb (2014-10-22 14:09:30)

Mazda Miata trigger

Background

The Mazda Miata is one of the most popular spec race cars in use in Sweden. One very successful combination is to put the 99-01 NB engine in the early 90's cars. The leading race car drivers here in Sweden wish to run with the stock trigger as they want the option to run the car on the stock engine management system if there is a problem.

I am developing a plug and play harness for these cars and I would like us to look at the trigger to see if we can make this work reliably.

Trigger system

Work in progress. The information available about the trigger is currently insufficient for a trigger implementation. Most of the information I have found on the web is very obviously incorrect.

The crank and cam sensors are hall triggers on the 99-01 Miata NB engine. The teeth on the crank look like they are made for a VR trigger but it really is a Hall trigger.

The crank has four really tiny teeth 90 deg apart. It looks like the triggers occur around 270,180,90 and 0 deg BTDC. If that is the case the decoding is straight forward as the cam trigger occur before TDC.

The cam trigger wheel looks like this, the engine is at #1 Compression TDC:

Just to make it clear: Is that 3 campulses total ? 1 lonelypulse, and (positioned opposite) a doublepulse ?

2014-10-15%2011.32.45_1024.jpg