I went to the dealership today to get a few things done and then asked about 87 octane gas and how my engine was kinda knocking. She (the rep) stated that if it starts knocking to increase the oct to 89 then 93.

Later on that day, I put in 93 and had no knocking issues (like I knew it would do).

I know the differnce in gas and etc, but why should I have to increase the oct when my car only has 20,000mi on it?

I use the same gas (shell) from either 1 of 3 different places.

EDIT: This has been going on for a bit now (2 months or so), nothing new.

 

could have been jsut a bad batch and the higher oct. cleaned it up...

i usually do prem. once every 3 fillups or so... but

now im sc so only premium gas...

 

sounds more than just a bad batch of gas if it has been going on for quite some time...

scion doesn't rec. using anything but 87. i say go back to the regular octane. if it keeps doing it there's obviously something wrong with the car and they need to resolve it due to it being under warranty.

no way would i waste my $$ on a higher grade because they say so. If they still suggest doing it, bring back the receipts and have them reimburse you. it's not your problem you should be paying for a higher octane when your user manual says 87, it's theirs. the car is under warranty, so be it.

i would be personally be infuriated.

I would actually just call corporate over it. It sounds as if they don't want to honor yoru warranty and deal witht he problem. Go to another dealer. See what they say. If you get the same thing call Corporate. Telling you to use a higher octane is ridiculous. They didn't print the user manual from their dealer. SCION DID.

This could also transfer over to bigger problems. They could say, "well you've been using a higher octance and Scion does not rec. that, therefore this voids your warranty."

I would just call corporate over the matter if you keep getting that response.

 

BE SURE to get "her" name in case future problems come about...

 

with a compression ratio of 9.6:1 i always did use 89 or 93.

 

yeah I agree that they is an issue there and using higher octane gas is not the solution. using the higher octane will just cause problems with the cat and other things over time. Go back to the dealer and tell them you want it looked at.

taco...the manual says to use 87 why would you use higher?

 

Totally agree!

 

i would experiment maybe with another top tier brand like 76 or chevron.

(i never did find toyotas to like shell extremely much, but it's worth a shot)

 

i dunno i think its a waste of money if u go 93 all the time i use to do that and it was jus pointless in my eyes im not boosted or anything.

BUT when i had my jetta i use to put 93 on it and watever lil noise i had in the engine bay would go away with it

 

I put 93 in just because it's a better grade of gas.. I don't care about the octane rating. 93 is filtered more than regular gas or something. I'd have to look up the differences, but octane rating is only one difference of many. Less carbon I think too?

But as far as the dealer telling you to put higher octane to see if it'll go away, they shouldn't have done that. I would've told them i'll try a different brand name of gas but I wouldn't pay more because they told me so. Then if the knock continued i'd tell them to start tearing down my motor and trouble shooting.

 

agreed. go back to 87, find a different gas dealer, if the problem persists, go back to the dealer and have them service the car.

good luck!

 

We have had this issue every once in a while. 2 things recommended by technical assistance. Try different gas and/or increase octane. There is most likely nothing wrong with your engine. If there were it would always be doing it at any octane level

As for Scion only recommending 87. That is completley false. In the owners manual it says 87 or greater. Or something like that. I could see you have a claim if they said 87 only, but Scion doesn't say that.

 

put 87 in it. if it blows u get a new motor under warranty

 

if i have like a quarter tank of 87, can i switch to 93. is it OK to mix gas?

 

Yes you can mix octanes safely.

Todays fuels are differant than those of 20 years ago.Back then higher octanes fuels ran cleaner and detonated later allowing for less knock.

Today all fuels carry the same cleaners in them at all octanes.......one possible problem is water in the gas.When I did my training for engine repairs we did several tests on gasoline......some brands had up to 30% per gallon that was water.....this came mostly from Arco which is very high on Alcohol in their gas.....in fact we found it to be way over thge advertised 10%.As alcohol breaks down and separates it releases a lot of water and can attract water.

Shell also was one that came up high on water content......Texaco was the best out there but they are almost all gone and bought out by Shell.

This time of year as temps drop gas companies swap to winter blends for the gas and as such may have a higher water content in it.

Dealership can do a fuel test to find out the content of water in your tank.

 

you need to read.. http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

and stop wasting your money... "filtered more than regular gas or something"?? you can't really be serious...

 

x2! When I was not supercharged, I ran 87 all day long since the car ran fine, I only needed to "up" to 91 since I am supercharged and the fuel map is tuned for the premium fuel! Anyone using more than 87 in a stock tC (even if you have header and/or intake) is wasting their money!

 

I noticed a slight knock sound on my car the other day. Is a slight knock ok ? Doesnt sound damaging but i can hear it.

 

open up your gas lid, see what it recommends.

 

lol