Mazda Miata trigger
Can someone take a look at this triggerlog, I have a wierd double trigger on each pulse. It shows up on the scope as well. The car runs on the stock engine management system. We are changing a few components to try to get rid of the problem but so far we have had no luck. Do you think that it can be generally ignored in firmware?
http://www.vems.hu/files/JorgenKarlsson/miata/v3.3_u009005-2015-02-10-14.49.33.triggerlog
Hello Jorgen,
I have reviewed your triggerlog, this shadow pulsing is a hardware problem and should be treated as such, perhaps doing some scope measurements will give some insight into whats causing it. most likely cause is ign noise. - DB
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
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.
This is what I found when scoping the car. This should be sufficient for implementing the trigger. It could be a degree or two off here and there as it was taken with a scope on an idling car.
As the crank trigger pattern is not symetric it's probably simplest to decode to a 4+1 trigger by counting and ignoring teeth.
Possible pseudo code for the input filter:\nÿ1ÿ
Note: this implementation depends on sectrig : Even if it has distributer (which I don't know), and same ignchannel configured for all 4 entries; it depends on working camsync, and will NOT limphome with broken sectrig.
They are not 90 degree apart, they are asymetric. something like 70-110-70-110 degrees.
I have trigger log of this. It is correct - Can you publish triggerlog ?
I removed 2 teeth, and got 2 x 180degree teeth and ran waste. Starts every other time.
Now i need Cam sync. /Thorbjörn
- After removed primtrig teeth (don't remove in new installs), maybe camsync can be configured with
- max_prim_per_sec_count; //maximum primary pulse per sectrig pulse for sectrig filtering
- I think probably no.