Detonation problem?

cepowers18 · May 9, 2008

I put the "?" in the title b/c I have no idea if that's my issue or not, but here is what's happening...

So I didn't adjust my timing myself (my mechanic did at least 6 months ago or more), but it is currently at 12 degrees. For awhile after he adjusted it, when at WOT I would hear sort of a slight ticking / scraping noise coming from the engine. At the time I was using 89 octane gas so I took this as a sign that 89 wasn't high enough. I switched to 93 octane and ran it for awhile and occasionally I would hear the noise but by and large it went away.

Literally, just the other day I decided to try switching back to 89 again since gas prices are obviously high. At WOT with 89, I started hearing the noise again.

Other than the obvious (switching back to 93) does anyone have an idea as to what may be going on... and/or can anyone explain why it's happening?

Any help is much appreciated :TY:

cepowers18 · May 9, 2008

Also I think my rear main seal is leaking, so I'm not sure if that would be causing it... or if the timing/octane is the culprit.

2slo95fiveoh · May 9, 2008

i would bump your timing down to 10* with 89 and see if the noise is less frequent.

idro · May 9, 2008

If you're hearing pinging WOT back it back a hair. And run 93 in it. I dunno if this is your daily driver but if you are going to mod/timing advance you gotta pay to play. Also by your rear main leaking it just happens over time. Mine is leaking on my cobra aswell, i just keep putting oil in it for now as it gets low. Don't ahve enough money for that ATM. Just a few drips under your car, eh? Thats what is happening w/ mine.

cepowers18 · May 9, 2008

Yeah, just a little dripping. I'm gonna have to get a good look under it tonight. It isn't my daily driver normally, but I drive it more frequently in the spring/summer/fall :coolsmiley: I have a Cavalier that I drive to and from work.

I talked to my mechanic back home and from the way I described it to him, it sounded like a valve might be floating? I don't know what that means... any help here?

Sorry for beating this topic to death though (timing & octane)... I'd like to be able to advance or retard my timing myself but I don't have a timing light, nor do I know what I'm doing. Anyone know where a good sticky is for timing? I've been searching on this site but I can't seem to find one :wall:

cepowers18 · May 9, 2008

Cool, so I just found the sticky with pictures. Sounds easy enough. Now I just need a timing light. Does it matter too much which brand I get, or how much I pay for it?

So I've been through a ton of timing posts and I think I have the process down pat, but my last question is do I need a special socket to loosen the distributor hold down bolt?

ddrracing · May 9, 2008

cepowers18 · May 10, 2008

Ok, cool. I'll check it out this weekend... thanks everyone :thumb: :TY:

KansasCityGT · May 12, 2008

cepowers18 said:
Cool, so I just found the sticky with pictures. Sounds easy enough. Now I just need a timing light. Does it matter too much which brand I get, or how much I pay for it?

So I've been through a ton of timing posts and I think I have the process down pat, but my last question is do I need a special socket to loosen the distributor hold down bolt?

There is a tool that makes it easier to reach that bolt. It's pretty cheap. Also, you could barrow one from O'Reily's.