Quote:
Originally Posted by gmtech16450yz
No, tow/haul mode has no direct effect on PE mode.
It's all tied to pedal position on these particular engines. In the stock Ford engine calibrations, PE does not come on until your foot has physically pushed the pedal down past 90% for a full, uninterrupted 60 seconds. (Sorry to yell, I just wanted everyone to fully understand exactly how it works. lol.)
This is a really big deal because if an engine doesn't get proper power enrichment it runs dangerously lean, creates excessive heat, is FAR more apt to knock or ping and of course won't make the power it's capable of. The fact that Ford tied PE to pedal position is pretty crazy. Most every other OEM has it tied to actual engine loads, throttle position or a combination of both pedal and tps inputs. Having it tied to pedal position makes the way some aftermarket companies modify those engine calibrations even more inefficient. Like I said earlier, if you tune the engine so that the throttle goes wide open when your foot is only half way to the floor, the engine will NEVER see PE in those situations. You can show power increases in a dyno chart, but when the customers are actually driving, you've actually REDUCED the power from stock levels by basically disabling PE. Scary stuff.
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This is really interesting and, as you say, somewhat scary. So it appears that with either stock or 5 Star the take away for mountain or other high load driving (which is most of the time with a big gasser!)is to avoid using cruise control because it won’t move the pedal enough to engage PE. And in manual driving to use all of the pedal travel while keeping the vehicle speed low enough that engine revs generally stay around 4,000. I tried that on today’s drive and it’s actually not difficult. A bit slower than I might otherwise drive but not bad. Alternatively you could manually flog the beast like a rented mule using the full pedal to drive 70+ mph. It would often be turning as much as 5,000 rpm which apparently isn’t ideal from a power perspective but at least you’d not be scary lean. And you’d get dreadful mileage. With the former strategy the vehicle accelerates easily because the engine is “happy” and you have to let up if you want to keep the rpm at around 4,000. With the stock tune you might not time out the 60 second delay and never enter PE.
Or did I totally misread your posts?
Thank you for the education. My old brain is trying to learn new stuff here!
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