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?

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

I haven't figured it out yet.

What is your AFR during this?

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.

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.

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.

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.

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?

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.

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.