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Ignition coils 2, 3, 4, 5 not receiving signal

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Hi there, I had a mechanic come over after months of me trying to diagnose misfires (see here). He determined the first and sixth coils are receiving signal to fire, but not two three four and five. Checked the spark plugs and 1 and 6 are burnt black, 2-5 look sparkly clean and looked like the fuel injectors did their job. I checked the ports on the DME, and they're all pretty clean (no oil residue wicking up into it).

I just replaced the DME and Fuel Injector relays (sky blue and white green) and it slightly fixed the issue. I used to get misfires on all 4 cylinders at once around 640RPM, now I'm just getting misfires on cylinders sporadically, roughly around 800RPM. It also takes the check engine light a bit longer to turn on. I've checked and replaced all 5 fuses in the engine fuse box.

Checked live data with a scan tool. I rev to about 3000RPM and let it drop, and the spark adv goes from about ~20 to -4.

I read that the pins on the last (furthest right) plug on the DME, send signals to the ignition coils to fire. Is there a way to check that the DME is sending a signal to fire? Is there another fuse or relay that could be faulty which is causing these cylinders to misfire? Ground issue?

Thank you guys, appreciate it.
1 - 2 of 2 Posts
Have you actually checked the spark at each coil using a new plug or a spark tester?
That would tell you if you are getting a spark. If you get a spark you are getting a signal.
I use an adjustable spark tester because you can get a better idea of the spark strength.
Crank shaft sensor faulty maybe?
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Hi there, I had a mechanic come over after months of me trying to diagnose misfires (see here). He determined the first and sixth coils are receiving signal to fire, but not two three four and five. Checked the spark plugs and 1 and 6 are burnt black, 2-5 look sparkly clean and looked like the fuel injectors did their job. I checked the ports on the DME, and they're all pretty clean (no oil residue wicking up into it).

I just replaced the DME and Fuel Injector relays (sky blue and white green) and it slightly fixed the issue. I used to get misfires on all 4 cylinders at once around 640RPM, now I'm just getting misfires on cylinders sporadically, roughly around 800RPM. It also takes the check engine light a bit longer to turn on. I've checked and replaced all 5 fuses in the engine fuse box.

Checked live data with a scan tool. I rev to about 3000RPM and let it drop, and the spark adv goes from about ~20 to -4.

I read that the pins on the last (furthest right) plug on the DME, send signals to the ignition coils to fire. Is there a way to check that the DME is sending a signal to fire? Is there another fuse or relay that could be faulty which is causing these cylinders to misfire? Ground issue?

Thank you guys, appreciate it.
1 - 2 of 2 Posts
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