98 NB dwell settings with stock coilpacks - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 06-20-2016, 07:23 PM   #1
TBJ
Newb
Thread Starter
 
Join Date: Apr 2016
Posts: 18
Total Cats: 0
Default 98 NB dwell settings with stock coilpacks

Hi,

I mentioned this in passing in my other thread but I think there's more to it than I realised.

What are the 'correct' cranking and running dwell settings for a 98 (99) NB with the stock ignitors? I am using a TC4427 with the inputs connected to the D14 and D16 outputs.

The default cranking dwell in the DIYAutoTune basemap is 8ms but at that setting it just backfires and hangs the starter up like there is way too much advance. If I change the dwell to 3ms it will start but is very hard to start. once started it runs relatively OK.

Are these dwell settings atypical for the stock coilpacks on the NB? Is something screwy about my setup?

Cheers.
TBJ is offline   Reply With Quote
Old 06-21-2016, 10:47 AM   #2
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,266
Total Cats: 51
Default

Make sure the spark outputs are at 0V with the key on and engine off, not 5V.
Matt Cramer is offline   Reply With Quote
Old 06-21-2016, 02:06 PM   #3
TBJ
Newb
Thread Starter
 
Join Date: Apr 2016
Posts: 18
Total Cats: 0
Default

Yep, 0v with key on but engine not running.

LEDs flash as expected when the coils are firing.

This is the ignition driver circuit I'm using:



One thing I've just realised... I'm using 10 ohm resistors in place of 15s there (it was what I had, and I assumed the function of the resistors is just to limit inrush current to the mosfet gate inside the coils).

Also I'm using a TC4424 instead of a TC4427... supposed to be functionally the same but have a higher output current ability.

Could that have anything to do with it?

Cheers.
Attached Thumbnails
98 NB dwell settings with stock coilpacks-6qyfrly.png  
TBJ is offline   Reply With Quote
Old 06-25-2016, 07:45 PM   #4
TBJ
Newb
Thread Starter
 
Join Date: Apr 2016
Posts: 18
Total Cats: 0
Default

I've set the cranking dwell to 6ms. Now starts on the button. Not sure why it doesn't like 8 still, perhaps I have weird coilpacks.
TBJ is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Rev MS3Enhanced, MSM, first run issues TheIglu MEGAsquirt 25 06-07-2016 11:43 AM
MegaSquirt-III ECU w/ MS3X, LC-1 Wide Band, Miata 1.6L, READY TO RUN! - SO CAL vortexblue Miata parts for sale/trade 8 06-06-2016 01:19 PM
DIYPNP 00 Miata No Start davidh99 MEGAsquirt 11 06-03-2016 01:18 PM
Yet another MS3 + VVT in a 1990 that won't start albumleaf MEGAsquirt 5 05-27-2016 08:38 PM
Diyautotune site is down. looking for base tune NicDrilling ECUs and Tuning 3 05-22-2016 11:30 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:03 PM.