01MGGT

Ok so my car is a 01 GT with the mods below that I know of as I bought it used. When I bought it it had flows welded in and a k&n filter. I added the rest so far. Ok so first of all gas here in Alaska is ****ty. As far as I know this car has a stock tune. But when I first got it (no matter where I bought gas it seems) I get a rattling that sounds liek valve noise or maybe ping at WOT in the higher RPMS. If I add a think of quality octane booster to the 87 before filling up it's fine and I don't think I have ever heard it ping. Anyway at all to tell if it has a different tune without hooking up to a tuner? As I don't have on yet. Should I just run higher grade gas and be done with it? The highest we have here is 90 octane if I am thinking right. Have already changed plugs with a fresh set of NGK and are properly gapped (platinum).

dimebag

Yes run good gas, baby it, or get something to pull timing

01MGGT

So are you prety much saying to keep running the octane booster if it makes it go away?

devongarver

If it truly does go away when you run octane booster in the tank, then it definitely is detonation. There are some things to consider here. While it certainly may have an aftermarket tune in it, there are other causes for detonation. You could have a failing EGR valve, you motor could be running too hot, if you have high miles you could have carbon buildup that will actually change the compression(this is not so common with EFI) etc..

What worries me, is that if there is indeed a tune that has been loaded into your computer, and not a physical chip that has been put in place, then your stock tune is gone. This means your PCM may not play nice when you try to tune it in the future, without taking your car to a Ford dealer and having them reflash it for a buttload of dough.

Now, to avoid the detonation without changing the tune, you can run higher octane fuel as you have been, or try a step colder plug. But this is assuming you are running at proper temp and your EGR is working properly. You could also throw in a 180* stat as well. I'm not sure what else to recommend.

98redstang

I get the same noise! i never heard of anyone else with this problem. It doesnt affect performance at all but its mad annoying.

devongarver

Please tell me this statement is a joke...

OK, you have a professionally built motor...and you are getting dentonation???? Who tuned it, how long has it been making this noise, is it only at WOT or under load, does it go away of you put 93 in it??? This is bad news and will harm your engine if you continue. It will either turn your piston into swiss cheese, or shatter it... You could have valve train noise, timing chain clatter, or a number of things, but if you have detonation you need to stop opening her up and get her retuned asap. pull the plugs and look at them, if there is yellowish residue you are likely running to hot and getting detonation.

nickmckinney

Clean or swap the MAF first, a dirty MAF is known to cause knock at WOT.

jtfrog

Mine does it when I get desperate and run low quality fuel. Chevron 87 runs great on stock tune

98redstang

Its not a ping its more of like a light rattling i guess? Its hard to explain... I don't think its detonation. I wish someone else could here it and tell me what the hell it is. I know what pinging is and its not that. The guy who did the motor took i and got it dynoed out in Pa where the shop is. I've been wanting to get it retuned cause he just did a conservative one.