90 miata ms3 installed, now no tach
#1
SadFab CEO
Thread Starter
iTrader: (3)
Join Date: Sep 2012
Location: your mom's house phoenix, AZ
Posts: 4,560
Total Cats: 1,142
90 miata ms3 installed, now no tach
i installed an ms3 in my 1.6 miata and after lots of user error i finally got it running, but no instrument tach. i tried a 1k resistor bewteen ig- to 12v and from ig- to gnd at the diag and also a 1k from 2I to 12v and to gnd at the ecu connector... no results. i tried them separately and together.
any other ideas? the only thing i can think of is i had the spark out transistor in backwards in the megasquirt and they possibly went low for sometime while i was trying to figure it all out. i felt the ignitor get very hot, its amazing i didnt blow up my coils and that the car is running great. but, did it fry the tach out circuit in the ignitor? did it fry the tach?
i have an o-scope i can put on it, its just so hard to see outside in the bright light and its big with no stand.
details in build thread start around page 5
https://www.miataturbo.net/build-thr...4-74776/page5/
any other ideas? the only thing i can think of is i had the spark out transistor in backwards in the megasquirt and they possibly went low for sometime while i was trying to figure it all out. i felt the ignitor get very hot, its amazing i didnt blow up my coils and that the car is running great. but, did it fry the tach out circuit in the ignitor? did it fry the tach?
i have an o-scope i can put on it, its just so hard to see outside in the bright light and its big with no stand.
details in build thread start around page 5
https://www.miataturbo.net/build-thr...4-74776/page5/
#4
SadFab CEO
Thread Starter
iTrader: (3)
Join Date: Sep 2012
Location: your mom's house phoenix, AZ
Posts: 4,560
Total Cats: 1,142
i had the resistor just stuck in the pins prior, this time i crimped on some spades so im sure it has good contact. still nothing. i verified continuity from the ignitor connector to the resitsor lead itslef and it checked out good. resistor measures 998, i tried another anyway. still no tach.
#10
SadFab CEO
Thread Starter
iTrader: (3)
Join Date: Sep 2012
Location: your mom's house phoenix, AZ
Posts: 4,560
Total Cats: 1,142
i forgot to update this. so for future reference:
this is what i had on the scope. never mind the fact that its absolute garbage, and didnt change frequency with change in rpm, its also only about 0.9V P-P. my scope could not hold a trigger on it, which tells me it was scattering.
i grabbed a used ignitor from ebay for $30, and...
so an ignitor can just have the tach circuit go bad, and still measure ok.
this is what i had on the scope. never mind the fact that its absolute garbage, and didnt change frequency with change in rpm, its also only about 0.9V P-P. my scope could not hold a trigger on it, which tells me it was scattering.
i grabbed a used ignitor from ebay for $30, and...
so an ignitor can just have the tach circuit go bad, and still measure ok.
Thread
Thread Starter
Forum
Replies
Last Post
elesjuan
Build Threads
9
11-14-2018 12:18 PM
JacksonRacingEngines
Engine Performance
10
09-10-2015 09:52 AM