Really odd cold related problem - 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 11-26-2008, 12:38 PM   #1
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default Really odd cold related problem

So I just got back from Pitt for thanksgiving, and the car is acting odd. When it is cold (its like 38* here) It takes a lot of cranking to start, which seems like ASE and crank pwm settings, which I am tuneing.

But when it does start, it has the symptoms of running on two cylinders. It seems like while it is under 170* oil temp, and under 2500 rpm, it runs on two cylinders. As soon as it warms up it purrs and runs great.

What the heck should I check? Could it be one or two of the COP's? Maybe one of the spark drivers in the megasquirt?
cardriverx is offline   Reply With Quote
Old 11-26-2008, 01:39 PM   #2
Elite Member
iTrader: (9)
 
Join Date: Aug 2006
Location: Concord, North Carolina
Posts: 4,173
Total Cats: 5
Default

mine will do that whenever it feels like it, sometimes it cranks and idles ok in warmup, sometimes it runs like ***.

I haven't figured it out yet.
miatamania is offline   Reply With Quote
Old 11-26-2008, 07:16 PM   #3
Elite Member
iTrader: (21)
 
paul's Avatar
 
Join Date: Jun 2006
Location: Point Pleasant, NJ
Posts: 2,957
Total Cats: 2
Default

What is your AFR during this?
paul is offline   Reply With Quote
Old 11-26-2008, 07:25 PM   #4
Junior Member
 
Join Date: May 2007
Location: San Diego
Posts: 383
Total Cats: 0
Default

Ive had the somewhat the same problem. Sometimes when i start the car after letting it sit for 30mins-1hour the car idles like complete crap and super lean. 2 days ago i set the afterstart enrichment past 85degrees(Current average temperature) all to the same value (25). So far, no problems.
jobambo is offline   Reply With Quote
Old 11-27-2008, 01:08 AM   #5
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default

Quote:
Originally Posted by paul View Post
What is your AFR during this?
super lean because of the unburnt fuel being dumped on it from the two non firing cylinders. I could even smell it... trust me the car has run on two cylinders before, I know what its like.


Tommorow imma try taking a hairdryer to the MS, and if it starts fine with the MS warmed up, it must be something on the PCB. If that doesent work, ill try heating the COPS or whatever else I can think of.
cardriverx is offline   Reply With Quote
Old 11-27-2008, 01:16 AM   #6
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,796
Total Cats: 248
Default

Collectively, how many times have you had problems with your MS? I think something on the board is fucked up. I dunno what though. But you've had problems before where it turned to be something you did wrong. Be it solder bridges, or slag shorting something, etc.

I'm serious. If I were you, and I had some money, I'd either

a) buy another kit and build a MS being very careful and through throughout the build
b) buy a pre-built MS from someone with soldering skilllzzz

Or c), fix everything that's fucked on your board. But troubleshooting electronics when you're not a smart electrical wiz isn't fun. If you wanna start somewhere, I'd start by replacing all the components for the output circuits on the MS. The resistors, the NPN transistors, etc. And this time be very careful when solering, do NOT overheat anything, etc.
patsmx5 is offline   Reply With Quote
Old 11-27-2008, 01:52 AM   #7
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default

a is out of the question because of money... All my last problems were because of a faulty 36 pin connector, so while I agree I might have fucked something up, its not the first thing on the list


maybe someone that knows alot about electronics can chime in.. if I did over heat say a resistor or something when soldering, would that cause it to be overly sensitive when cold?

What causes electronics to screw up when cold?

If a COP is bad would this be a symptom?



If tommorow I heat up the MS with a hair dryer and it starts fine, then I will totally agree with you pat, I mush have fucked something up on the bord.


Quote:
Originally Posted by patsmx5 View Post
Collectively, how many times have you had problems with your MS? I think something on the board is fucked up. I dunno what though. But you've had problems before where it turned to be something you did wrong. Be it solder bridges, or slag shorting something, etc.

I'm serious. If I were you, and I had some money, I'd either

a) buy another kit and build a MS being very careful and through throughout the build
b) buy a pre-built MS from someone with soldering skilllzzz

Or c), fix everything that's fucked on your board. But troubleshooting electronics when you're not a smart electrical wiz isn't fun. If you wanna start somewhere, I'd start by replacing all the components for the output circuits on the MS. The resistors, the NPN transistors, etc. And this time be very careful when solering, do NOT overheat anything, etc.
cardriverx is offline   Reply With Quote
Old 11-27-2008, 08:48 PM   #8
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default

I warmed the MS until it was almost hot, made no change. When I warmed the COPS, it started pretty quickly. maybe it was a coincidence, but is it possible for a COP to be sensitive/not work in the cold?
cardriverx is offline   Reply With Quote
Old 11-28-2008, 11:30 AM   #9
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,266
Total Cats: 51
Default

Quite possible - often when an electrical component is acting up, the first sign something is wrong is it doesn't work when the weather gets colder.
Matt Cramer is offline   Reply With Quote
Old 11-30-2008, 12:54 PM   #10
Senior Member
iTrader: (6)
 
Join Date: Jul 2007
Location: Cocoa Beach, FL
Posts: 808
Total Cats: 3
Default

I would definitely say it's the COP. You can always pull the plugs and see which ones are firing when they're cold to see if it's just one or 2 or all of them having a hard time.
TrickerZ is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Hey everyone another n00b here Big_gumby Meet and Greet 80 10-05-2015 05:06 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 01:45 AM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
Got bad Crank Angle Sensor and Random Misfire codes, but runs fine. Greasyman General Miata Chat 2 09-28-2015 11:44 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 12:57 PM.