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Old 12-01-2009, 11:21 PM   #21
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Try the capacitor and change out the ignition mod resistors to 270-330ohm. That'll make sure your COPs are getting what they're supposed to for voltage and signal. It could be part of what's causing the problem. I was originally thinking it could be a CAS problem, but it should happen with the stock coils. It's possible it's still the CAS signal and it's the fact that the stock coils charge over a longer period of time which causes less parasitic current draw allowing a cleaner signal. If that's the case, the capacitor should still fix it, but the filtering capacitor b/w JS8 and GND is still a good idea. If all else fails, add more grounds to everything.

Oh, and another thing, check your COP wiring harness. Make sure all the connections are clean and tight and there are no cold solder joints. Temperature can easily change how well it works if it's degraded in some way. Make sure the gauge of the wiring is correct for the application, too. If you used really tiny wire, that could be a problem.
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Old 12-01-2009, 11:26 PM   #22
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Have you updated the spark circuit in your megasquirt according to the current DIYAutoTune setup. Namely, they changed the resistors on the triggers.
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Old 12-01-2009, 11:37 PM   #23
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Quote:
Originally Posted by Saml01 View Post
Have you updated the spark circuit in your megasquirt according to the current DIYAutoTune setup. Namely, they changed the resistors on the triggers.
If I said there was a chance I was still rocking my KingofL337 mods to my megasquirt would you have any clue what I am talking about?

I will pull out my MS tomorrow and take a look at it and see what resistors I am using where. I am pretty sure that Scott and I have updated my MS to something somewhat recent. Not sure If I have upgraded to the Joe is Awesome and makes **** work mods yet.

I will also try to get a video of it running bad.
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Old 12-02-2009, 02:08 AM   #24
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i'm going to try the spark mod first. if that doesn't work i'll add caps. thanks everybody!
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Old 12-02-2009, 06:37 AM   #25
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Have a look at your rpm trace in mlv. When I had missfire issues similar to Joe they showed up as either a drop to 0 or a peak to eleventy billion. If that's the case then unfortunalty there is no known cure. Both Joe and I gave up and switched to crank wheels.
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Old 12-02-2009, 09:37 AM   #26
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this is not the case, when it misfires the rpm value just suddenly drops, it doesn't bottom out or peak.
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Old 12-02-2009, 02:48 PM   #27
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finish the brap brap brap build and you won't have to worry!
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Old 12-02-2009, 05:45 PM   #28
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Maybe the problem you're experiencing is different altogether. If your car sits for an extended period of time..overnight, maybe oil or coolant is seeping into the combustion chamber and when you start it, the engine is trying to burn off whatever is in the combustion chamber?
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Old 12-02-2009, 06:17 PM   #29
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If the CAS wiring runs near the COP wiring, it can cause misfires. This will be much worse without the 10,000 uF (or 2 x 4,700 uF) capacitor.
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Old 12-02-2009, 11:48 PM   #30
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Quote:
Originally Posted by NoMiEzMX-5 View Post
Maybe the problem you're experiencing is different altogether. If your car sits for an extended period of time..overnight, maybe oil or coolant is seeping into the combustion chamber and when you start it, the engine is trying to burn off whatever is in the combustion chamber?
Then why would I not have the same issues with my stock coils?

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If the CAS wiring runs near the COP wiring, it can cause misfires. This will be much worse without the 10,000 uF (or 2 x 4,700 uF) capacitor.
Interesting theory, but why would this only cause issues when it is cold out?

Sorry I haven't gotten a vid yet, raining out this morning and it looks like tomorrow morning is going to be to warm. Although I might try anyways.
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Old 12-03-2009, 01:31 PM   #31
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Quote:
Originally Posted by NoMiEzMX-5 View Post
Maybe the problem you're experiencing is different altogether. If your car sits for an extended period of time..overnight, maybe oil or coolant is seeping into the combustion chamber and when you start it, the engine is trying to burn off whatever is in the combustion chamber?
i know this is partly my problem. my valve stem seals are destroyed, my car blue smokes every time it starts, and this has probably fouled up my plugs to some extent, but i know this is a separate ignition issue.

The cas wiring idea is one i haven't considered. that would make sense why it worked before and now works like crap, maybe the wires moved around a little.

I'm probably just going to swap out the resistors and if that doesn't work just deal with it. my rotary is already rebuilt, i just need a few odd parts here and there before i swap it.
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Old 12-03-2009, 05:33 PM   #32
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Then why would I not have the same issues with my stock coils?



Interesting theory, but why would this only cause issues when it is cold out?
It doesn't. I wasn't trying to explain the cold hard start issue, just a general pointer.

Can you try this experiment. If you are sure you have hard starting every morning, do this.

One night, take your COPs out and keep them warm indoors. Plug them in in the morning, and see if you still have hard starting. This will rule out the COPs themselves as having a cold related issue.
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Old 12-03-2009, 09:01 PM   #33
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Quote:
Originally Posted by JasonC SBB View Post
It doesn't. I wasn't trying to explain the cold hard start issue, just a general pointer.

Can you try this experiment. If you are sure you have hard starting every morning, do this.

One night, take your COPs out and keep them warm indoors. Plug them in in the morning, and see if you still have hard starting. This will rule out the COPs themselves as having a cold related issue.
I will try that out next time it dips down into the 30's in the morning. Although I have 2 sets of cops and both do the same thing. So I am highly doubtful it is the actual cops. One of these days I will have my friend try out my harness to see if that is the problem.
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Old 12-03-2009, 10:06 PM   #34
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There might be some design related issue common to all COPs, not a unit related issue.

It's unlikely the harness if others are seeing the same problem.

What are your dwell numbers for cranking?
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Old 12-04-2009, 09:42 AM   #35
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I've never had a problem with cold starts since I've fitted mine, I can start/idle the car without problems as low as 20*F, about the coldest I've ever tried. usually stays in a garage if it's that cold and never gets touched.
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Old 12-04-2009, 10:36 PM   #36
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Whats the verdict on the spark circuit>?
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Old 12-16-2009, 11:15 PM   #37
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final verdict:
- switched the cops for a stock coil and wires
- pulled plug #1, it was brown, didnt even check the other 3
- set the dwell back to where it needs to be for stock coils
- didn't change out the resistors on the megasquirt yet
- changed no other settings in megatune

car started on the second turn over while it was sleeting. I've since dailyed it with no problems at all. the missing issue is completely 100% gone.

I dont know what was up with my coils, maybe they were damaged? they were from a toyota tundra so their plug was off at different angle from the ones savington likes to use on his kit he used to make. their appearance is exactly the same as the coils everyone else uses though, and they were wired on the same pins. I dunno.
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Old 12-22-2009, 02:44 AM   #38
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Mine do the same thing when cold, I doubt both of ours are bad considering they run great in warm weather
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Old 12-22-2009, 03:16 AM   #39
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i have the same problem i need to hire joe for a weekend
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Old 12-22-2009, 04:05 AM   #40
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Quote:
Originally Posted by Braineack View Post
I've never had a problem with cold starts since I've fitted mine, I can start/idle the car without problems as low as 20*F, about the coldest I've ever tried. usually stays in a garage if it's that cold and never gets touched.
What's the P/N on yours, so that we can have a "Trully Tried & Tested" list...?

Jim
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