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Discussion Starter · #1 ·
Hello,

This issue is actually about my daily driver (I know... not the GTR, but I'm hoping someone will still help) that I'm having issues with. I'm getting a misfire in Cylinder 2. I just recently changed the coil pack on this cylinder... Here are my troubleshooting steps:

1. Switched coil packs from cylinder 3 to cylinder 2 ~ Still a misfire in 2. Coil pack that was in 2 is firing in 3 (testing by holding coil boot close to a ground to see the spark jump.)

2. I could get power from the terminal clip of cylinder 2 using a test light, so I know power is moving through the wires.

3. Replaced clip. Confirmed it was soldered the right way. Still a misfire.

4. Confirmed voltage is the same coming out of clip 2 and clip 3. They both have the same voltage... but there is still no spark jump to a ground from the Cylinder 2 boot.

Also, since testing for the spark jump I ruled out a spark plug issue, but they were replaced 2 weeks ago.

So heres what I have:

It isn't a Coil issue... and it isn't a wiring issue... and it isn't a voltage issue... what the heck am I missing? Maybe the plug isn't making a good connection to the coil pack? but I can't really see that since it's in a plastic housing... so I'm not sure.

This issue is for a Mazda 3... I'm completely lost and I know it must be something easy.. Any help would be much appreciated.. Thanks.
 

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Maybe water or moisture in 2 spark plug tube. That or ECU problem
 

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Discussion Starter · #5 ·
Maybe water or moisture in 2 spark plug tube. That or ECU problem
Yeah, its just weird because I'm actually getting voltage to the plug. And when I run a test light to the plug it strobes like it should. So I'm completely lost on why it's not causing the coil (which is good) to spark. I'm going to mess around with it more when I get off work today.
 

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You're gonna want an LED to test it.

Most coils have a three wire setup. One power, one ground, and one signal. Signal is generally handled by GROUNDING. So you could get a LED, and tap it from Power, and Signal, and it should pulse on.

I've done this plenty of time with a little bit of wire and a noid light (for fuel injector signal testing). However, not knowing your car is, it's hard to say for sure.
 

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Discussion Starter · #8 ·
Thanks for the replies!

This issue is for a 2004 Mazda 3. 2.3L. I'm ruling out a spark plug issue because I'm testing if the coil will spark (with the coil out of the engine. I'm holding it near a ground to look for an arc. (or spark) The only one not sparking is any coil connected to cylinder 2. All the coils will ARC to a ground if it's plugged into any other terminal besides the cylinder 2 terminal...

So I suspected the terminal may be going bad as it is getting old and the plastic started chipping away. I soldered a new terminal ( or plug) into the wiring harness and it looks like its getting the same amount of volts as the other terminals... but I'm still not seeing a spark....

I just gave up on the whole thing and shipped it to a guy I know to look at it. So now 2 of my 3 cars are down & out. :p

Again, thanks for all the help.
 

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Give us an update, when able. Interested to see what the problem was.
 

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Discussion Starter · #10 ·
Give us an update, when able. Interested to see what the problem was.
It looks like the ECU (ECM, PCM w/e you feel like calling it) isn't sending a ground signal to make the coil fire. So I'll need to order a new ECM and get it flashed.
 

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It looks like the ECU (ECM, PCM w/e you feel like calling it) isn't sending a ground signal to make the coil fire. So I'll need to order a new ECM and get it flashed.
Woohoo. What do i win?
 
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