getting DETONATION

[paco]

What could be causing this? It happened on my way to work today, it's weird cause on the drive here on the freeway I went full boost(10psi) and everything was fine. Then when I got off the freeway I drove for about two miles and still everything cool, then right before I got to work I stepped on it a little and at about 4-5 psi I got detonation (really loud too). What could be the problem? I just got new spark plugs and a new 02 sensor a few weeks ago. I have an SDS by the way.

[mike969mb]

Running premium? How's the fuel mixture running? You do have an air-fuel ratio gauge correct?

[COgalant]

All I know is it better be running in time for our meet or I will not be a happy camper...not that you really care https://www.thegalantcenter.org/style_emoticons/default/smile.gif

[paco]

Running premium? How's the fuel mixture running? You do have an air-fuel ratio gauge correct?

Yes, I am running 91 octane, that's the highest I can get here. the a/f gauge I didn't see that when I heard detonation but I think it read lean, not sure though.

COgalant.- I really don't care how you are going to feel man....jk. I just want to get my car running good. I thought it was..... I guess not https://www.thegalantcenter.org/style_emoticons/default/sad.gif

[ChikagoGTZ]

Maybe you didn't gap the spark plugs right and extra fuel wasnt used therefore what you heard was when the fuel ignited somewhere in your exhaust system. Prolly shot a flame out your ass too!

Your PSI could have gone down due to a vac-pressure loss in the intake mani due to your our lovey anti-knock system retarding the ignition....just my guess.

[paco]

well, the gap is 44 like RIPP says.

[BlankMan]

paco - refresh my memory - are you stage 1 or 2? V6 or I4?

J

[paco]

stage 2, I4

[BlankMan]

Ah - that's right. Well then, you can dis-regard the anit-knock timing suggestion by ChicagoGTZ - we (I4's) don't have a knock sensor (sorry Dave https://www.thegalantcenter.org/style_emoticons/default/smile.gif

Do you also have the injection cooler? If levels were low and your BB or injector unit were calibrated to injection around 3-4 psi, that might cause detonation...

Other than that - you have another 'unique' problem - you're good with those ! :wink: I mean, after all, if you just went to 10 psi with no problems and only noticed it at the one occurance of low boost, that seems almost backwards.

Have you dyno'd yet? Remember, the true purpose of a dyno run is to check rich/lean conditions and make sure you're running safe. I'd definitely suggest getting that done to help diagnostics.

J

[paco]

I am going to the dyno on wednesday. I do have the boost cooler and it's set go on at 5psi. But like I said, detonation ocurred at like 3-4 psi