3A90 Intake valves stuck open, carbonized, full of gunk and car won't start

[gone.a]

Such a wierd case. Reminds me of this

https://youtu.be/Duf53hK05Qo

Not implying OP used wrong fuel, just showing what funky fuel can do. Maybe a local gas station put a few gallons of the wrong stuff in the wrong tank? How is it possible to have such an issue on cars with as little as 6000 miles?

Any of our Philippino or Thai members seeing reports of this on non English forums? That engine has been around for a few years now.

If there is a software fix in the works we should be able to one day find a technical service bulletin on the issue which should have at least a sentence or two regarding the cause.

[Mitz]

foama may I ask .. in your oil changes have you ever used any oil additive?

When the engine was opened to clean up the gunk, were the piston rings checked?

[deleted user]

OP stated he had no egr.

regards
mech

[deleted user]

foama, you stated that the last fill was several hundred kms from your home. I still suspect fuel contamination.

You left the station and drove several hundred kms home?

That was the last possible variable introduced into your system and the car was not shut off until you reached the place where it was parked overnight? No possibility of anyone tampering with your fuel?

If the answers are yes, then that points more specifically to bad fuel.

regards
mech

[foama]

No oil additives, just Mitsubishi's own branded oil.

No oil overfill, practically zero detectable oil consumption between yearly servicing intervals.

No EGR
Remember, This is a 1.0 L engine, different Head than the 1.2L.

[BRagland]

No oil additives, just Mitsubishi's own branded oil.

No oil overfill, practically zero detectable oil consumption between yearly servicing intervals.

No EGR

If there was little to no oil consumption, it could be that the PCV valve broke on your last drive, and what little consumption there was, happened all at once, causing the problem. Could also be a gasket going and what little consumption there was, happening all at once.

There is a huge different between 1 cup of consumption in 3,000 US Miles vs 1 cup of consumption is one hour over 100 US miles. Believe it or not, that could be it. Highly unlikely as it may be, it's possible.

Other than an issue with your PCV valve or some magical gasket failure, you have only one option: bad gas. I hate to point this out, but you might need to get off the high horse and realize it could very well be bad gas. No rudeness intended, but even stellar gas stations can be run by crooks using old gas to save money and impress the regional manager. Not everyone is honest. Including those working at otherwise respectable places.

There is nothing else to explain it, sorry to bring the bad news hammer.

[foama]

Other than an issue with your PCV valve or some magical gasket failure, you have only one option: bad gas. I hate to point this out, but you might need to get off the high horse and realize it could very well be bad gas. No rudeness intended, but even stellar gas stations can be run by crooks using old gas to save money and impress the regional manager. Not everyone is honest. Including those working at otherwise respectable places.

There is nothing else to explain it, sorry to bring the bad news hammer.

No rudeness percieved. I would be very happy if it were just bad gas, but that local company using half a dozen 3A90 Mirage has had each one repaired during the first year with the same trouble, and some have come back again. They drive short distances in town, and fill up locally.
I drive long distances only, and fill up at good brand stations wherever I need gas. Usually far from my home and rarely at the same place. Both cases same problem, only thing in common is the type of engine...

I will just have to wait and hope there will be no re-occurence.

[Daox]

What is the software update supposed to do?

[cyclopathic]

What is the software update supposed to do?

I am guessing it is the same update as for CVT to lean out idle. That would help with carbon buildup and if car had EGR with intake valves.

[foama]

What is the software update supposed to do?

Presumably ECU software. No idea what the changes are supposed to do, or what they are...