Just wondering if any one has run across a chip or simple tuner that will force the pcm into open loop @ wot operation. The vehicle is a 1997 f-250, 7.5 liter, 5spd speed density system, Iv'e got tons of mods on this engine which are pretty well useless pulling a load up a steep grade because the pcm decides to go into closed loop @ wot throttle.
Any thoughts ?
Thanks, Dom

 

I wonder if a custom tuner would be able to do that for you. I know the people who tune the diesels can work wonders with things like that.

 

My experience is that that would be most unusual for any engine, and also that the later 1994 to 1997 SD 460s only ever go into closed Loop going downhill.

I just saw your other post on this; I may have more after digesting it.

I read your other thread with your scanner log. If you can post the "Catch Code" from your ECU I may be able to confirm this, but I believe your scanner has reversed the sense of the flag, and it is reading Closed Loop when you are in open loop, and it says Open when you are in closed.

The catch code is probably 3 letters followed by one number, that is in a font about 3 times bigger than the other part numbers. It is written on the outside of the 60 pin ECU socket, facing the engine, so you may need a mirror to read it. The catch is the code for the programming of your ECU. It may be something like "HHX0".