check engine light with 87 octane

[Mangix]

whenever i use 87 octane fuel, my check engine light comes on. when i use 89 or higher, it doesn't. Anyone know what the problem is?

I drive a 2002 Toyota Camry V6. Last time someone checked my car they said it was because of the fuel mixture. but they didn't give me the code or anything. Just said something is wrong with the mixture.

[johnfrisco]

Originally Posted by Mangix

whenever i use 87 octane fuel, my check engine light comes on. when i use 89 or higher, it doesn't. Anyone know what the problem is?

I drive a 2002 Toyota Camry V6. Last time someone checked my car they said it was because of the fuel mixture. but they didn't give me the code or anything. Just said something is wrong with the mixture.

You need a new Knock Sensor.

[Mangix]

really?

i know they fixed that problem in the 3MZ-FE but a 2002 1MZ-FE engine is still affected?

[Agent556]

i thought the recommended for the 1MZ was 91/93 octane because of the knock sensors? correct me if wrong...

[gdanaher]

If things are working correctly you can use 78 octane and the engine will adjust timing to accommodate the poor fuel. Check the error code it presents with 87 octane fuel, but I also vote for the oxygen sensor.

[Mangix]

Originally Posted by Agent556

i thought the recommended for the 1MZ was 91/93 octane because of the knock sensors? correct me if wrong...

it's recommended 91 but it's 87 minimum. dunno why it causes CEL to come on. I mean 89 doesn't make it go on...

but yeah, i think i'll go to a repair shop so they can check it and so i can report back.

[fenixus]

if o2 sensors (v6 has 3 or 4 of them) can screw up Air/Fuel ratio pretty bad. my suggestion would be to put some 87 octane fuel in tank (e.g. a few gallons) once you running low fuel and make it show the CEL. then go to autozone and scan error codes for free.

once you know what they code says it will point you towards the right direction. it might be that one bank of your V6 runs lean with poor fuel while the other one runs OK. that would rather point to o2 sensors in that bank.

I have no idea what a knock sensor does and why would it react to worse fuel, but i need to dig deeper with my car as well ('00 4cyl 5S-FE california). it has bad MPG since a few months. for some reason it detects lean mixture at fuel closed loop (idle or cruising) and ECM adds like +20-30% of fuel to make the mixture right.

[JohnGD]

Check a local parts store that will read out the code for free.

Originally Posted by Mangix

whenever i use 87 octane fuel, my check engine light comes on. when i use 89 or higher, it doesn't. Anyone know what the problem is?

I drive a 2002 Toyota Camry V6. Last time someone checked my car they said it was because of the fuel mixture. but they didn't give me the code or anything. Just said something is wrong with the mixture.