Odd misfire cruising in town - 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 10-26-2012, 11:17 PM   #1
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Oct 2009
Posts: 1,436
Total Cats: 58
Default Odd misfire cruising in town

When I went from naturally aspirated to supercharged, all I had to change in the tune was the boosted cells and acceleration enrichments and the car ran great. I'm naturally aspirated again, and retuned the acceleration enrichments, but otherwise left the tune as is.

I've got 93 octane in my tank with some Chevron Techron.

Cruising around town today at about 3000rpm; 30-35mph , I got a series of misfires. I got out my phone and started logging, and was able to capture a few of the misfires.

Any advice in fixing this would be helpful. I never had any issues with misfires on this tune in the past. My cruise is usually around 15-15.5 AFR. The engine made a quick jolt, followed by the rich AFR dip.
Attached Thumbnails
Odd misfire cruising in town-graph.png  
Enginerd is offline   Reply With Quote
Old 10-27-2012, 02:24 PM   #2
Junior Member
iTrader: (5)
 
Join Date: Mar 2012
Location: Gilbert, Az
Posts: 337
Total Cats: 26
Default

How old are your sparkplugs/wires/general ignition components? Can you pull the plugs and check their condition?
SJP0tato is offline   Reply With Quote
Old 10-29-2012, 01:13 PM   #3
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Oct 2009
Posts: 1,436
Total Cats: 58
Default

Plugs and wires were replaced about a year and a half, less than 20,000 miles ago. I probably still have colder than stock plugs on the car, come to think of it.

I'll put new OE plugs in.

It's interesting in that it happened in 'normal' operation...the base fuel table VE value and ego correction acheived the AFR target I was commanding. My AFR targets in cruise are 15.5-15.8, and although it's worked in the past, I'll also trim these back to 15.3.
Enginerd is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1991 special edition with hard top full part out JC, NJ russian Miata parts for sale/trade 6 10-08-2015 04:01 PM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM
Got bad Crank Angle Sensor and Random Misfire codes, but runs fine. Greasyman General Miata Chat 2 09-28-2015 11:44 AM
Missfires on idle and cruising (no load) emarkey DIY Turbo Discussion 2 09-05-2015 07:59 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 01:02 PM.