Shaun@ AED explains #8 failures.

[Grandpa]

What do you think?

Originally Posted by Shaun@AED Just a little more info (nothing too technical) on what's going on these days with regards to Coyote engine failures. Those engine builders who have seen these kind of engine failures are keenly aware the problem is a LEAN condition at WOT. This is evident by the type of piston damage seen. Spark knock creates a sharp break in the piston, lean conditions melt the piston. Ford has adopted what others in the industry have used for quite a while. Lean A/F to create a 'broader' torque curve. Below is a dynograph of an Twin Turbo Mercedes E63 on both the Stock tune and aftermarket. Note the flat TQ curve of the stock tune and check out the crazy lean Air Fuel! This is the EXACT same thing Ford programed into the Copperhead Coyote/Roadrunner ECU's. In our case it's triggered by the Torque Calculations. As we reach the TQ limits in the tune, the ECU pulls fuel to create a 'broad' torque curve. How do they not blow up the engines you may wonder? Exhaust temps are monitored and in the case of our Fords, Cat enrichment is initiated at a given exhaust temp to combat Cat failure. Below is a screenshot of a STOCK 2012 5.0 with this condition in full view: Yellow line is COMMANDED Lambda and as it approaches 1.0 (14.1 Air Fuel) Fueling enrichment kicks in to save the Cats from damage (inadvertently saving the motor as well). So why don't we see this on a chassis dyno? Check out the time it took for the lean condition to start....when was the last time you saw a WOT dyno run last 15+ seconds? AED and their tuning partners found this late last year (Dec 2011). Once the offending Tune parameter was found we started testing on my own 5.0 with E85 in the tank to insure against any potential engine damage. Compression tests were done pre and post fix as well. Further investigation showed more ways in which this lean WOT condition was triggered, but instead of investigating each one individually we found the commanded fueling for these conditions and modified it correctly. As of Jan 2012 ALL AED tunes have this 'fix', as well as our tuning partners/buddies and ANY tuner that has called me and requested this information. Of the hundreds of 5.0 tunes sent out between all of these tuners, not ONE has had an engine failure since the 'fix' has been implemented. Some of my tuning partners have requested I refrain from posting specific technical data on these public message boards, but I prefer to have a more informed customer base.