melanieg78

ive noticed that my manual says its ok to use 87... however what does everyone else use? ive noticed a "pinging" noise ? do i need to do at least 89?

Abom

You shouldn't need to use anything more than 87 octane rating. All vehicles sold in North America are tuned to run optimally on 87 octane. I'd be tempted to say something else might be up...

TwotoneVert

I forgot what car you had. If this is the one you just purchased, the timing may be bumped a little and will require higher octane. You can lower the timing and get rid of the pinging, if that is indeed the issue.

NorCalTroy

That isn't entirely true Martin. There are several vehicles types sold in North America that are actually tuned to run on 89, 91, or even 93 octane. Not all of them are tuned for 87. We don't know the make, model or even year of Melanie's car so we don't know for sure.


Melanie,
Pinging is usually pre-detonation. Pre-detonation means the fuel is actually combusting before the spark plug fires. The main causes are either the timing too far advanced, or you are running too hot of a spark plug.

You don't state what year of vehicle you have so it's hard to tell what the exact cause is. If you have an older car without a PCM (computer), it's easy to adjust the timing to get rid of the pre-detonation. If you have a PCM and want to change the tune, it can be done, but you would have to take your car to a tuner or use a chip.

If you don't want to retard the timing, re-program the PCM, or run a cooler spark plug, you can run higher octane fuel to compensate.

Either way, it is bad for the engine for this to happen so you want to get it fixed as soon as you can.

Good luck!

Abom

Actually, yes, you are correct, I jumped the gun assuming which vehicle it was. If it's an naturally aspirated, they should all run on 87, unless specifically mentioned by the manufacturer. I know here in Canada, even VWs and Mercedes are "de-tuned" from the factory to run on 87 octane.

melanieg78

i have the 2007 gt premium

NorCalTroy

It being a brand new car, without any mods, Martin's original thoughts are correct. There should not be any pinging from the recommended 87 octane. Is it happening all the time, or just under load? Has it always done it? Assuming it is still under warranty, you might want to call the dealer where you bought it and explain the problem to them as adjusting the timing yourself is more-or-less out of the question and spark plug issues shouldn't be present since I'm guessing the original plugs are still in the car.

Good luck! Keep us posted.

jaded seconds

time for some warranty service

TPony

Welcome to the forums!

SOHCman

I've had a problem with detonation since it was new.

Been in the dealer several times and they say everything is OK.

They even replaced the MAF and now the pinging is WORSE!

I can't really complain too loudly as the pinging happens outside of the posted speed limits...

Next year I get a tuner and decrease the spark advance over 2500 RPM.

SOHC

PS: 93 octane did not cure the problem either.