Multiple Ignition Coil Failure

Link a thread that covers this if there is one. I cannot find it. I asked this same question on YotaTech and no one replied LOL

2009 Tacoma TRD Sport crew cab short bed

I have a misfire that I cannot diagnose or correct. They are always on the driver side of the engine. changing coils does correct the issue but only for about a month maybe. To date, I have installed 6 spark plugs and all coils on this engine (8 coils purchased). I swapped the only bad one first. then it "went bad" a week later. I swapped that coil again at a shop. That misfire would only happen after the truck got up to temp and was under acceleration. Then it happened again, same coil plus one other. I got frustrated at this point and did all plugs with OE plugs. At the same time I put in 6 new OE coils I bought from a dealership online. One of the coils had expanded/exploded and been contained by the block. I drove it a bit then went to NJ and back to VA after installing these coils. Boom, non driveable misfire again. Check engine flashing, lurching, sputtering.
I truly don't think this is a coil issue. Something is blowing my coils. I cannot keep dumping money but don't know what I should do. What I should expect a dealer to do or anything else for that matter. I am desperate to be honest guys and looking for some help.

Coils: UF495 90919-02248
Plugs: OE

$9 90919-01235 Toyota Genuine Spark Plug

90919-01235

 

Did you buy oe Toyota coils or standard ignition blue streak coils?

 

OE coils. I put the part number at the bottom of the post. The first two replacement coils were from Autozone and Napa (shop bought this one).

 

Its been a minute but ive never seen any toyota oem part number start with UF.

 

Your saying the coils are physically melting?

 

I dont know what the UF number is but the part number he has listed is an oem toyota part number for the coils 90919-02248

 

This will be interesting to follow but Im guessing there must be a way to measure the output at the harness. Im not sure what numbers to look for but that's my guess at where to start. Then trace back from there. Someone much smarter than me will chime in at some point.

 

You would need an oscilloscope to check the control and feedback signals, Power and Ground can be checked with a high current (preferably 5 amp) test light.

I can't see any reason for coils to melt unless the ECM is holding them on too long but I've never seen one with excessive dwell time, I've seen other vehicles where the coil driver in the ECM will get stuck on and melt a coil down but those were all with direct control coils.

In any case, at the coils:

Pin 1 (Black/Red): Ignition Power (Battery voltage with key in Run & Start)
Pin 2 (White/Red): Ignition Feedback (5v, Each coil pulses it to Ground when it fires)
Pin 3 (Different color for each cylinder): Ignition Timing (Coil Control), ECM sends a 4v pulse to fire the coil.
Pin 4 (White/Black): Ground at all times.

 

I Knew this was going to be beyond what my driveway is capable of.
Yes, I added numbers to the part number, thanks for that.
Toyota told me $200 to do diag work on it and it would take up to a week. it is only a 20min drive but I don't think I could make it. So that will add a really expensive tow onto the price.

 

I will look for the picture of the melted coil. I was shocked when It came out of the engine.

Thank you at DM93 for such a detailed post. And everyone who cared to reply. Emotional support is appreciated!

And by the way.... I DEF MISS MY HiLUX! None of this computer stuff!!! LOL

 

You'd have to have some weird high voltage leak to blow a coil like you describe.
And multiple coils doing this?
Or just the one coil that "exploded".

 

I found the photo

 

So far, only one that looked like the photo. The others are just frying/stopping

 

Only times I've seen coils melted like that it was either a coil driver getting stuck on in the ECM or shitty coils.
I've never seen a coil driver get stuck on on a vehicle with indirect coil drivers like Toyota though, not to say it can't happen.

I'd certainly want to take a scope and compare bank 1 and bank 2 coils though.

I doubt a dealer would have a scope or even know how to use one, most dealer techs follow the troublemaker flow chart in the FSM and don't think outside the box.
Honestly there's not alot of independent shops that have or use a scope either which is unfortunate as it's a powerful diag tool especially for weird issues like this.

 

We would scope IGT on this but it really depends on which tech gets it. Not many use the picoscope often in my shop.

The last time I got this problem is was due to aftermarket performance coils, the entire back #2 failed on a 3.5 tacoma and they all had blistering, it was truly odd.



A full bank misfiring is odd, I'll be following to see what happens.

 

Those RIPP coils are junk, so many people have had issues with those but they still keep buying them.

I rarely have to replace a coil on Toyota stuff, when I do it's usually a failed aftermarket one not an OEM one.

 

I agree, this is truly odd. Maybe I can find a performance shop that will do it.

 

The plugs are correct, that shouldn't cause a resistance issue.
If it were a block ground, I'd suspect it to happen at all times.
Not a week later, or when it gets up to temperature under a load.

Like others said, a scope would be the next test.
Need to see what is happening at the coil control.

 

I suspected a block ground. It is only happening on the driver side of the block. That has to mean something right?

 

Except the coils all share the same power and ground, unless the wire is corroded/broken in the harness between bank 1 and bank 2 which seems unlikely but possible.