going from 91 to 87 gave me CEL! FLAME ON

[enviri]

i've been driving my yaris ever since i got out of the lot with 91 (93 when possible) and never gave it any thought....now since read the forums, i might as well give it a try, so basically i had 2 tanks of sunoco 87 (loong drive today, CT to ME and back, family thing) and on the 2nd tank, after the fillup, CEL showed up! I wonder if this will go away for the car to readjust timing, since its the first time the car had a tank of only lower octane lol...first tank didnt count since it was 91/87 inside. what do you think? btw im ordering a scangauge tommorow.

[supmet]

Need to know the CEL code(not tightening the gas cap can throw a CEL) You can go down to auto zone(don't know if they're east coast but I'm sure there's a part store equivalent) and use their tester for free while you're waiting on the scangauge.

[enviri]

i double checked the gas cap, and took off the neg terminal overnight and see what happens.

[The little red pill]

that's what you get for using 87 octane. Not only do I use 93, but I add octane booster to give me about 97 octane. I even have a NOS sticker on my car to prove how cool I am!

Seriously though, most likely the gas cap! I had it happen to me on a different car. I actually had to get a new gas cap, because the rubber gasket on mine was bad.

[CtrlAltDefeat]

Originally Posted by PK198105

87 wont give you a CEL unless there was water in the fuel. the owner's manual even tells you to use 87 octane. you're wasting your money for nothing

my 08 manual says 87(research 91)

[CtrlAltDefeat]

looking at it now, my 2008 Owner's Manual says on page 347: "Unleaded gasoline with an octane rating of 87 (Research Octane Number 91) or higher.

[CtrlAltDefeat]

I just wonder what "research number 91" means... sounds like 91 preferred, but it will run on 87...

[CtrlAltDefeat]

dunno... doesn't really make sense for them to tell you to research the less preferred rating when 87 is common and cheapest...

[Kaotic Lazagna]

Cheapo gas? I go from premium to regular (premium at least once a month), and I never had a CEL come on. I only use Chevron as well.

[IllusionX]

guys guys guys... RON91 = PON87

in Europe, they use Research Octane Number, while in NA, we use Pump Octane Number. That's why you see 100+ octane numbers in Europe. Their gas is no different than ours. hehe.

[ROCKLAND TOYOTA]

GREAT, another gas subject that will bring out all the experts. how about giving us that code you threw so we can see whats up......

[Tamago]

Originally Posted by ROCKLAND TOYOTA

GREAT, another gas subject that will bring out all the experts. how about giving us that code you threw so we can see whats up......

he reset his ECU before checking it.



FAIL

[Tamago]

Originally Posted by PK198105

that i didnt know thanks for the info the RON PON one

ours is actually referred to as (RM)/2

[IllusionX]

Originally Posted by Tamago

ours is actually referred to as (RM)/2

It's actually (R+M)/2. (RON + MON)/2.

anyways, wikipedia is a good read.
http://en.wikipedia.org/wiki/Octane_rating

[mikenacarato]

Originally Posted by The little red pill

that's what you get for using 87 octane. Not only do I use 93, but I add octane booster to give me about 97 octane. I even have a NOS sticker on my car to prove how cool I am!

Seriously though, most likely the gas cap! I had it happen to me on a different car. I actually had to get a new gas cap, because the rubber gasket on mine was bad.

you know you will foul your plugs out right? octane increased additives will burn them up. if you have been doing it for a few tanks, pull a plug and see if its turning an orangy burnt color. your eating away the electrodes.

[IllusionX]

Originally Posted by mikenacarato

you know you will foul your plugs out right? octane increased additives will burn them up. if you have been doing it for a few tanks, pull a plug and see if its turning an orangy burnt color. your eating away the electrodes.

As is, higher octane will not do any harm, nor give better performance/mileage.

The only thing is that SOME companies put cleaning additive to their premium fuel. If the engine is not knocking, there's no reason to put higher octane fuel.

/end of discussion.

[mikenacarato]

your wrong, why do you think we cant put race fuel in our cars for extended periods of time...it will burn them up because they will run too hot.

[Kal-El]

Why do some of you insist on using high octane? The Yaris was designed and calibrated to run on regular 87. Using premium may do the same type of long term harm as using regular in a car that requires premium.

And why waste the money?