DFI open/closed loop problems

[Zachary Zehnacker]

On Tue, 7 Apr 1998, Andris Skulte wrote:

> idles around 875-900, though). The high limit is at 2000 rpms. From what
> I have it set at, the DFI will go to open loop below 750, above 2000,
> above 70% TPS, or below 120 degrees coolant (yes, it is F). Problem is

	I don't think that the 2000 rpm high limit is really an upper 
limit for closed loop operation.  I believe that the high limit is the RPM
that much be reached before the DFI will switch into closed loop (while
RPM is increasing) and the low limit is the RPM that much be reached
(while RPM is decreasing) before the DFI goes to open loop.  Having two
values just keeps the DFI from constantly switching back and forth between
open and closed loop like it would if there was only 1 RPM limit for
closed loop operation.  If my understanding is correct, your setup would
have to go up to 2000 RPM before closed loop operation would begin.  It
would then stay in closed loop until it dropped below 750 rpm.  If it did
drop below 750 and come out of closed loop it would then require the
engine to reach 2000 RPM again before going back into closed loop.  I hope
someone will correct me if I am wrong in my understanding of these two
limit settings.  The manual isn't very clear about them.

   I also don't think I remember seeing anywhere that the DFI actually
tells you that you are in open or closed loop.  The only way that I have
found is to see if the oxygen sensor is correcting the mixture (on the
'V' screen) or when the bar on the fuel map screen comes on to show you
what your mixture would be if the unit were in open loop.

   I think your 30 lb injectors might be the reason you are having to
lean out the maps so much.  I think the stock maps are usually setup for
18-20 lb injectors.

        Zak