ski

FWIW
Just recently I noticed slight pinging in the 4-6K rpm range at both POT and WOT with 93 octane gas and a 93 octane canned Predatortune. Sincepinging had never occurred prior to this, I did some research, and made alist of the possible causes and their cures.
Number 1is high ambient temperatures. But this was quickly crossed off the list since it was hotter last summer, and the engine did not ping then. Another reasonwhy high temperatures are not the causeis becauseit also pinged at night when the temperaturedipped intothe 40's.
Nextis a bad load of gas. Immediately before the pinging started,I had filled up at adifferent station than I normally use. So I ran that gas out without getting into the loud pedal, and filled up at my normal watering hole(Lukoil), which had never caused any pinging. But it did not go away.S..t! I have to stay out of the loud pedal for another 300 miles! Next wasSunocothat's supposed to be quality gas, but which I do notuse because it's 10 cents per gallon higher than Lukoil. Still no luck. So a load of bad gas did not look like the cause.
Next is adirty MAF, which can give the ECU an inaccurate signal, and excessively lean out the A/F ratio. Removed it from the CAI housing, sprayed it withsome quick drying electronics cleaner that I had laying around, and reinstalled it. No good. MAFis ok.
Next is a partially blocked fuel filter that can also excessively lean out theA/F ratio. But if the pinging was happening at POT, then that meantthe emission control system was in the closed mode, and the O2 sensors were active. In that case, an excessively lean A/F should have thrown a code. But since there was no code, I eliminated the fuel filter as a possible cause.
Next is eithera faulty spark plug or a plug wirethat's bad enough tocause a rich condition in one of the cylinders, but not bad enough to cause a misfire(which was not happening). At POT thiscan cause the O2 sensors to send a rich signal to the ECU, and the ECU willthen reduce the pulse durationfor all of the injectors, leaning out the mixture in theother 7 cylinders, and cause pinging. But once again, this should have thrown a code. Since it did not,a bad plugor plug wire was crossed off.
The lastcausemy researchfound was carbon buildup on the piston crowns, heads, and valves. But I did not think that this was possible since the car had only 17K miles on it.However, at a cost ofonly $7 for a can of Seafoam, I thought "What the heck!" Dumped a can of it into a full tank of gas last week, and after 225 miles the pinging is gone today.That stuff works. Well, it did for me. Plus, the engine idles smoother,revs faster, and has more punch. Where's that 427 AC Cobra that blew my doors in last summer?

NOTE 1: During the time the engine was pinging, I made various adjustmentswith my Predator to the global timing(retard), to the WOT timing(retard, 2-4K & 4-7K), and to the WOT fuel(rich, 2-4K & 4-7K) in order to eliminate the pinging.I found that the pinging could be stopped only if the global timing and WOT timing were both at their full retard settings, and the WOT fuel was atits full rich setting. But the car ran like s..t at those settings. So I reset everything back to default, and stayed out of the higher rpms(most of the time anyway).

NOTE 2: I may have to continue using the higher priced "quality" gas to possibly prevent this problem from rearing its ugly head again. NAH! I'll continue using Lukoil(cheapest gas around here), and just dump in a can of Seafoam if and when Ihearmore marbles rattling.

moosestang

I'm really skeptical of any fuel system cleaner. This stuff can't hurt anything?

A_J

Well if you want to abosolutely rule out gas, I've had the best luck with Chevron. Even then, last year they had a seasonal blendthat kept making the O2 trip codes in my BMW.

Otherwise it sounds like you're on the right track, might be lean, might be too far advanced, etc. I'd be interested to see how this plays out and if the Seafoam stuff keep the pings away.

ski

I used it after discussing the issue with my mechanic. He said that he has used Seafoam on numerous vehicles, including sophisticated OBD II vehicles like ours, with great success and no problems.

Wally39

A while back someone on another Mustang forum posted a video of taking off after putting seafoam in his engine. Talk about a nice trail of smoke. Must of cleared the carbon out lol. It was pretty cool.

Daniel60

Fu&k I thought I was back in school with all that reading. Just get to the point please. Oh yeah I hated school. Since I'm not really suffering denotation at the moment I'll just pass.

ski

I've ruled out the gas because the pinging continued when I initially pumped only a half tank of Sunoco withoutadding Seafoam, and the pinging stopped in 225 miles after adding the Seafoam and topping off the tank with more Sunoco from the same station.
The timing and A/Fare now set at theoriginal default settings, and there's no pinging.Thus the cause was not excessively advanced timing, or an excessively leanmixture.
I'll report back on how the engine is performing wrt pinging or no pingingin the near future.

ski

Sorry 'bout that for those wholike to cut to the chase. I know that I get that way at times.
However, I thought that the process of elimination in my post would be a good reference for those who experience the same type of pinging problem as me.

F1Fan

Your deposit buildup was caused by using cheap fuel that lacked the additive package needed to keep your valves and combustion chambers clean. Regular use of Top Tier Gasoline brands will avoid the problem all together and eliminatethe need for using products like Seafoam in the future. Look at this link for more information! Top Tier Gasoline

HTH!

owero01

+1. I only use Exxon or BP 93. Haven't had any ping problems. I also add Lucas or Marvel Mystery oil to the gas for top lubrication.