Odd Misfires with MSPNP9093. - 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 09-06-2010, 08:57 PM   #1
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Sep 2007
Location: Detroit, MI
Posts: 124
Total Cats: 0
Default Odd Misfires with MSPNP9093.

Hey guys,


My car has been seeing some hard misfires lately. They feel almost as hard as an overboost cut, but I've data logged and that is not what is happening. Instead, when I get the misfires, the data logs freeze everything. RPM freezes, AFR, PW... very odd. Attached is the log. Any idea on what's going on? When I run <10 PSI, the car runs OK... once I up to 12, it starts to misfire at high boost. I'm going to go bald ripping my hair out with this issue. Log attached with lots of spacebar usage when it happens. The logs have RPM drops at record 376 and 1032. Channels stop moving at records 1393 - 1406. Any ideas on what the cause or what I could do to fix this? Thanks.
Attached Files
File Type: xls datalog201009060007.xls (198.6 KB, 39 views)
zzyx7 is offline   Reply With Quote
Old 09-07-2010, 02:16 PM   #2
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,266
Total Cats: 51
Default

I did see the RPM drop to zero once, which COULD be a sign of a flaky CAS. This seems more like a noise issue, however. Any chance it could be spark blowout? Misfires can cause a bit of noise; try gapping your plugs tighter.
Matt Cramer is offline   Reply With Quote
Old 09-07-2010, 03:44 PM   #3
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Sep 2007
Location: Detroit, MI
Posts: 124
Total Cats: 0
Default

Thanks for the input Matt. I've been afraid of a bad CAS sensor. Would a bad CAS be more RPM dependent and not so much load dependent?

I'll try re-gapping the plugs. This has been a problem since I switched to COPs. I've run BKR7E's and BKR7E-ix iridiums, both gapped at 0.035". Maybe I'll reduce that to 030 and see if it helps any.
zzyx7 is offline   Reply With Quote
Old 09-07-2010, 05:49 PM   #4
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,266
Total Cats: 51
Default

Quote:
Originally Posted by zzyx7 View Post
Thanks for the input Matt. I've been afraid of a bad CAS sensor. Would a bad CAS be more RPM dependent and not so much load dependent?
I would not expect a bad CAS to be load dependent.

Quote:
I'll try re-gapping the plugs. This has been a problem since I switched to COPs. I've run BKR7E's and BKR7E-ix iridiums, both gapped at 0.035". Maybe I'll reduce that to 030 and see if it helps any.
Toyota COPs are, at best, an incremental upgrade over stock. You might want to go with an ignition with a bit more firepower.
Matt Cramer is offline   Reply With Quote
Old 09-08-2010, 12:32 AM   #5
Junior Member
Thread Starter
iTrader: (4)
 
Join Date: Sep 2007
Location: Detroit, MI
Posts: 124
Total Cats: 0
Default

Matt --

Thanks for the help. I gapped the plugs down, and the issue has gone away. I upped the dwell from 2.5 to 2.9ms based on this article https://www.miataturbo.net/megasquirt-18/dwell-observations-toyota-cop-44131/ and finalized gap at 030 and the car runs smoothly.

Rave reviews on the Toyota COPs led me to believe they had a good bit more juice than stock. What would you recommend for a high power ignition system?
zzyx7 is offline   Reply With Quote
Old 09-08-2010, 08:52 AM   #6
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by zzyx7 View Post
Matt --

Thanks for the help. I gapped the plugs down, and the issue has gone away. I upped the dwell from 2.5 to 2.9ms based on this article https://www.miataturbo.net/showthread.php?t=44131 and finalized gap at 030 and the car runs smoothly.

Rave reviews on the Toyota COPs led me to believe they had a good bit more juice than stock. What would you recommend for a high power ignition system?
Probably the badass one they sell that I don't know how to wire.
hustler is offline   Reply With Quote
Old 09-08-2010, 09:35 AM   #7
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

Quote:
Originally Posted by hustler View Post
Probably the badass one they sell that I don't know how to wire.
They need switched 12V, 2 power grounds, 1 logic ground, and trigger. I think you could handle that.
Ben is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Replacing one tire nigelt Wheels and Tires 7 09-22-2015 01:32 PM
mslabs MS2 - Idle control issue ndragun MEGAsquirt 0 09-20-2015 11:28 PM
Mystery Engine Trouble. Halp, mt.net! vehicular General Miata Chat 12 09-14-2015 04:17 PM
Missfires on idle and cruising (no load) emarkey DIY Turbo Discussion 2 09-05-2015 07:59 PM
Dumb question about crank and cam angle sensors AlwaysBroken Engine Performance 4 09-04-2015 02:35 PM


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 11:04 PM.