Higher octane = loss of power

[MontyCarlo]

It's my first time back on the forum in ages, and I'm hoping the internet's collective IQ can solve this problem.

My 2010 V6 is up to about 94k miles. I've been giving it 87 octane almost all that time, and it's been performing just fine. However, the other week, I gave it a tank of 91 to see what would happen. Unfortunately, what happened is that I lost power dramatically, the Check Engine light came on, and the computer threw out a P0008 error (the one usually associated with stretched timing chains). When I used up that tank and went back to 87 octane, my power came back and the Check Engine light went back off.

A few days ago I tried again, 89 octane this time, and again it's triggered the Check Engine light. The power is not so dramatically different this time.

So it looks like my Camaro no longer knows how to adapt to higher octane. What could be causing this? Major fix or minor fix?

[The Stig]

edited: miss read the OP's issue.

[rtcat600man]

Originally Posted by The Stig

The car is tuned for lower octane, so giving it higher octane just causes it to pull timing.

You maybe saying that backwards.

Many of us use higher octane to avoid the timing being pulled which reduces power.

As for the OP's issue, I have never heard of this issue.

But if it runs good and you are happy with 87 octane then stay with it.

For me, I have been using 93 for over 3 years now.

[RubyCamaro]

But using higher octane should not cause this to happen. Maybe your timing chain IS stretched & it shows up as a code only when you use higher octane & it tries to adjust???????????? Just a thought.

[Batmanntexas]

If you still have the powertrain warranty intact, I say throw a tank of high octane in it, get the P0008 code again, take it to the dealer and let them sort it out. The car is a direct injected gasoline engine, running like 11.5:1 compression, on 86/87 octane, so throwing some 91/93 in it, should not even cause it to hiccup. Just my $.02

[Evil-Bee-NH]

Ya what batman from texas said!



Sorry couldn't resist.

[KMPrenger]

I kind of agree with BatmannTexas.

If simply running premium fuel causes your car to run really badly (not just a little bit differently, but much worse) then I believe you have other underlying issues.

Many V6 owners run premium (91 octane and higher) fuels including myself, and never have issues. In fact I think this is the first time I've heard of something like this.

The V6 is designed to be able to run on regular octane, but can run on premium and we even have proof that it runs a bit "happier" on premium fuel so again, your issue is very strange.

If you have a warranty, and can get the code to show and and get your chains replaced I'd do it in a heartbeat. You have 94K miles, so its very likely that your chains could be stretched anyways.

[MontyCarlo]

I'm not really familiar with how the timing chain works - how would a slightly stretched one cause problems with high-octane fuel but not with regular?

[menendez1293]

Originally Posted by KMPrenger

The V6 is designed to be able to run on regular octane, but can run on premium and we even have proof that it runs a bit "happier" on premium fuel so again, your issue is very strange.

Three years here and the only time there has been a tank less than 93 Octane in my V6 is when it left the dealer. Seems kind of strange that you would be getting this issue with Premium Fuel.

[Ventmaster]

Originally Posted by MontyCarlo

I'm not really familiar with how the timing chain works - how would a slightly stretched one cause problems with high-octane fuel but not with regular?

The timing chain works by synchronizing the motion of the piston in relation to the intake and exhaust valves.

If the chain stretches and it results in the valves not operating perfectly in concert with the piston, performance, emissions, and in severe cases engine damage could occur.

My guess is your chains have stretched in the last 94K and when you're comparing low and high octane performance, you're stomping on that gas more often than usual- and that's what's triggered the CEL.

Get it back if you can, but if not you can still take it to the dealer and tell'em it's been coming and going- and you know what it means. If they're good guys they should take care of you while you're still in warranty.

[Evil-Bee-NH]

I think everyone mentioning the timing chain is spot on also you live in a cold climate area and the winter fuel blend isn't nice to our cars at all. Even at 93 octane the ethanol content is giher then they advertise in the winter blend because the gas is a little thicker. I'd have the chain checked out but i know i got all sorts of codes shortly after i switched to the winter blend fill-ups and some injector cleaner and dry gas got rid of everything. Not the issue your having but i'd spend the $5 for these for preventive care any day of the week during the winter months.

[The Stig]

Originally Posted by rtcat600man

You maybe saying that backwards.

Many of us use higher octane to avoid the timing being pulled which reduces power.

As for the OP's issue, I have never heard of this issue.

But if it runs good and you are happy with 87 octane then stay with it.

For me, I have been using 93 for over 3 years now.

you're totally right, I miss read the OP's issue.

Yea - higher octane shouldn't cause you to lose timing or anything. No idea what's going on with that.

[TooCool5]

Originally Posted by RubyCamaro

But using higher octane should not cause this to happen. Maybe your timing chain IS stretched & it shows up as a code only when you use higher octane & it tries to adjust???????????? Just a thought.

Originally Posted by Batmanntexas

If you still have the powertrain warranty intact, I say throw a tank of high octane in it, get the P0008 code again, take it to the dealer and let them sort it out. The car is a direct injected gasoline engine, running like 11.5:1 compression, on 86/87 octane, so throwing some 91/93 in it, should not even cause it to hiccup. Just my $.02

^^This^^

[Sikoriko]

Agree don't wait. When the CEL comes back take it back in under the warranty