Possible fried ECU; Need Help

[Shwaykid]

While at a stop light, my 08 Speed starting shaking and idling super rough. Light turns green, could barely get to 15mph. Luckily, I was literally 100 feet from my apartment complex. Limped it through the complex, then it completely died. I had to push it into a spot.

Here's what I find when I inspect stuff the next day:

**See attached photo**


Those wires are:

2BA (White) - Ignition Coil #1
2AW (White/Red) - Igniction coil #2
2AX (White/Blue) - Ignition Coil #3

They had been rubbing against the casing of my battery and I'm guessing arc'd out on each other.

**Positaps are for my Aquamist WMI kit**

Only thing I've done so far is cut out the bad/exposed section, and replaced with good wire.

Car doesn't crank, fuel pump doesn't prime. Also, Aquamist isn't turning on with KOEO like it normally does. That red wire Posi-tapped into the harness is 2BE Fuel Injector Relay, that supplied main power to the HFS4 board.

On top of that, I'm getting a "cannot connect to ECU" error every time I try to read codes or view gauges with my AP.

I don't have much experience testing ECUs but I have a multimeter, test light, and plenty of tools if anyone has any ideas or direction.

[Solarsurge]

Just throwing it out there, we are about to part out a 2009 Speed 3 within the next week or so. ECU, immobilizer, and full wiring harness will be available. Let me know whatever you need.

[SSinstaller]

Check your fuses. IIRC its fuse 30 for the pcm, but Id check them all.

[Shwaykid]

Originally Posted by SSinstaller Check your fuses. IIRC its fuse 30 for the pcm, but Id check them all.

Fuses were good. Going to check relays tomorrow. If I read the wiring diagram correctly, if the injector relay blows, the main relay can't get power. I'm hoping into that bit of hope

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[SSinstaller]

Unless I looked at the wrong diagram there is one 20amp fuse for the injector relay, coils, and ignition power to the pcm.

The main relay has its own 30amp fuse(12v constant). The pcm actitvates the relay with a negative trigger.

Pull and check every fuse in the diagram I posted. If none are blown you probably do need a new pcm.

[Shwaykid]

After verifying every relay and fuse in the engine bay was good, I moved to the interior fuse box.

Turns out the ENG 20A was fried. Replaced that, engine fired. Unfortunately, when those three Ignition coil wires burned out on each other at the ECU, it fried the units. Lots of nice white smoke... Thankfully no fire started.

Ordered 4 new coil packs. Hopefully that does the trick.

*side note, made sure to re-wrap the ECU harness with nice harness wrap to ensure this doesn't happen again...

[Shwaykid]

See attached for what a melted ignition coil looks like...

Only fried the number one coil. Unfortunately, the connector on the harness side also melted. Ordered a new one from here:

https://www.bmotorsports.com/shop/pr...sihu03j95mi2m7

While it's en route, I have the coil independently wired with .5mm female spade connectors. Should hold me over for a couple days while that new connector ships.

Overall, I consider myself pretty lucky. Only fried one coil plug, and had to replace about 6" of wire. Oh, the ground and power wire also fused to each other at the connector. No wonder I was getting the vape show and awful smell.