View Full Version : what does Detonation sound like

05-27-2005, 11:06 PM
i'm just trying to figure out if mine is detonateing or is it blowing out my spark due to a over size gap in my plugs and i have them at .54 the car on the dyno made a quick popping nosie coming from the exhaust and u could see a little bit of black smoke as well

05-27-2005, 11:10 PM
It sounds like a coffee can full of pennies.

05-27-2005, 11:10 PM
the guy told my my air fuel ratio was great he said i couldn't get no better but he also felt a big and better ic would help alot

05-27-2005, 11:13 PM
cool so popping from the exhaust is not Detonation because i know that guy knows all about that i mean u does deal with mustangs and all but he is a cool dude lol. he told me that the plugs are getting blow out so thats what i'll do then lol regap time man this sucks lol

05-27-2005, 11:24 PM
A coffee can full of pennies, so basically a rattling nosie? I have wondered this too? Any other ideas as to what it sounds like by chance? Austin

05-27-2005, 11:24 PM
Could be worse you could have killed the engine if the other had occoured. Back out if you even think you hear it ping. If you were to go lean for some reason it's possible to blow a headgasket or even crack a piston.


05-28-2005, 01:09 AM
It sounds like money draining from your wallet!! :D :D

XR7 Dave
05-28-2005, 09:53 AM
It sounds like money draining from your wallet!! :D :D This is the best description I've heard to date.

What is a "great" AF ratio and how much boost are you getting?

The 94 SC is programmed to run very rich. If it is not running very rich then it is also trying to put in too much timing and hitting the knock sensor. Our ignition systems are very good and don't normally "blow out the spark". If you experience conditions which appear to be spark blow out, then most likely you are also experiencing severe knock retard also and a certain amount of detonation.

How much boost does the car make?

Randy N Connie
05-28-2005, 11:54 AM
the car on the dyno made a quick popping nosie coming from the exhaust and u could see a little bit of black smoke as well

Mine has done this, with cold engine and I get on it,from a stop.


05-28-2005, 01:08 PM
Is detination also a backfiring sound with shots of black some coming out of your tailpipes and staining your driveway?....or is that just backfiring/missing?

Oh btw, what should fuel pressure be at the Schrader Valve with stock 30 lbs injectors and fuel pump. I just installed an AFPR and I want to make sure my fuel pressure is correct.

If I'm correct, with the vacuum line off it should read about 39 lbs. But, what does that equate to with the line on?

...I have some issues with my car...


05-28-2005, 01:13 PM
If you are asking about my car, it pegs the guage w/ relative ease most of the time. Otherwise it is a consistent 14-15psi in the upper RPM's. My buddy said that you can easily hear "ping(ing)" if a car is doing it, and mine is not. I understand it NEEDS to be tuned, and it will be soon. Otherwise I have only gone WOT once to see if the belt slipped, which it did so NAPA, here I come :p Austin

05-28-2005, 03:24 PM
Disregard. It's fixed. It was the FPR. I hooked it all up, set the pressure to 39lbs-static and cranked it up. It was rough for a while as the computer was adjusting and I was tweaking things. The vacuum read low on the gauge, but when I took it out and started driving the vacuum righted itself to 19-20 inches and the car was smooth as hell! :D