Detonation

[4.6Mustang35th]

i went to the all ford nationals this weekend and i got my car dynoed, the first run was fine, but the second two runs the lines looked like someones heart beat, the guy at the dyno said it was because my car was detonating..my car is basically stock, no power adders. any ideas what could be causing detonation?.... i'll try to post the dyno graph asap

 

[DBMSTNG]

bad gas most likely.

 

[NightLife]

^^^ what he said.... you could be running lean maybe...

 

[4.6Mustang35th]

i hope so, i put 93 octane in before i left, the guy said it could be spark plugs, but i changed them about 20,000 miles ago...

 

[DBMSTNG]

if your X pipe does cats, that may cause you to go lean. also, run some fuel injector cleaner. check the spark plugs to make sure they are fouled up.

 

[Red35th]

If you had a mass air I could see it, but I don't see anything on your car that would cause it to go lean enough to ping. Mabye it was just really hot, car's get pretty hot reving that high under load with no air through the radiator.

 

[4.6Mustang35th]

yes, it does have cats, not fouled u mean? lol thanks for the info i'll have 2 do that

 

[DBMSTNG]

yes, it does have cats, not fouled u mean? lol thanks for the info i'll have 2 do that

yeah, that.

 

[Red35th]

How cool is it that everyone in this thread but one has an LE??

Well I think it's cool.

 

[4.6_02_Black_GT]

not me ...just normal 2002 GT

 

[4.6Mustang35th]

it is cool!, i checked the plugs they look normal, the tips were kinda whitish tho..

 

[4.6Mustang35th]

a slightly brownish color is supposed to be normal right?

 

[Red35th]

yep, just a little golden brown is normal and good.

 

[wms004]

i went to the all ford nationals this weekend and i got my car dynoed, the first run was fine, but the second two runs the lines looked like someones heart beat, the guy at the dyno said it was because my car was detonating..my car is basically stock, no power adders. any ideas what could be causing detonation?.... i'll try to post the dyno graph asap

ford didn't tune all of our cars that well. I ran 91 octane on the stock tune, and I was detonating hardcore. So I had the car dyno tuned with an autologic chip. Problem solved, and i'm tuned to run 91 octane.
Detonating can eventually turn into a hole blown in a piston.. its worth the tune if you run 91 octane and still hear detonation.

-wade

 

[4.6Mustang35th]

thanks guys for all the help, these are some things that i will have to look into

 

[03gtmustang]

If your car is mostly stock and your running with the stock tune then use 87 octane. Otherwise get your car tuned for 91 or 93, whatever is in your area. With your next fill put in 87 and see what happens.

 

[wms004]

If your car is mostly stock and your running with the stock tune then use 87 octane. Otherwise get your car tuned for 91 or 93, whatever is in your area. With your next fill put in 87 and see what happens.

Wrong.. if he's detonating with 87, he needs to up the octane to see if it stops with 91+ octane. Why would he want to fill up with 87 again? If he's detonating with 87 or 89 its just going to continue happening. 91 and 93 have the most resistance to knocking/detonating.

last resort is a tune if it detonates with the highest octane that you can get locally.

 

[killbee]

it is cool!, i checked the plugs they look normal, the tips were kinda whitish tho..

If the plugs are white then you are running fairly lean. Make sure to look at all the plugs not just 1 or 2. Sounds like you need a good tune to be safe.