The limp-home system is techy but a foolish feature,IMO,........what dope is going to drive another 50 miles After the bottom has just dropped out of the cooling system and the Temp gauge is pegged!?! :?

the new system they're using can be used on any pushrod engine, no matter the # of cylinders (of course, you prolly wouldn't do it on a 4 banger, but anyway...). don't know if the *how* of the new DOD is public knowledge, so i'll have to dub out of explaining it, but it'* pretty cool, and the way it is set up now gives one amazing advantage over any system of old:

if the system fails, it will force all cylinders to be active

meaning you're never stuck with non-working cylinders.

and this will be GEN IV... DoD is the reason for the gen change...

matt

Pretty sure I read somewhere that when the cylinders de-activate the fuel injector to that cylinder/* shuts off, and solenoids in the rocker arms de-activate/close the intake valve/* and just leave the exhaust valve/* to function normally to release the compression of the cylinder and 'free-wheel' that particular piston stroke.............

Read this link, it tells you all you want to know about the 4.6 Northstar V8.
http://www.babcox.com/editorial/us/us100232.htm

good writeup!

what dope would drive 50 miles in limp home mode? My wife if it means the difference between her sitting on the side of the free way alone and getting home safely.

I hit limp mode once in my old Aurora, shreded a belt and water pump went out. Limp lasted for about 5 seconds till DIC said shut off engine imediitly. I kinda wondered before why limp mode didn't last, maybe because the temp gauge started getting closer to 250 than I wanted it too. car was never the same afterwards. but made me buy my ssei

"Car was never the same afterwards" this is a common statment, I think my Aurora was over heated before I bougt it, when I got it the radiator leaked very slowly, and for the last 67,000 miles (the whole time I've had it) it has had what sounds like a minor piston slap at cetain engine temps and loads.
Runs great though, currently 104,000 miles.

Getting a 4.6 in it in another 50,000 miles.

Please don't dig up old topics.