1994 Ford MPI 5.0: ECU in safe mode at low voltage?

Hi all.

After tracking an electrical issue with a 1994 FW Vista 278,
which consisted of loose power connections all across the house
12 volt wiring, fuel consumption dropped by 2/3.

That's right. The same trip that took a 1/4 tank to make
is now made 3 times on the same 1/4 which was confirmed after adding
100 litres of fuel which is 1/4 tank (404L).

The issue is mainly that the isolator was redirecting all power to the house
wire and the engines were always at around 11V.

So, does anyone know if Ford engines go into safe mode with
dumb, very scaled back parameters to get you back to shore?
And now that I get 13V on both sides, the engines ECU features
and fully used?

I noticed a very different sound and also scaling back
of the throttles to maintain plane (3000 rpm at 45KM/h).

Normally, I would just jump for joy, but it seems too good to be true.
I dont want to run lean and blow the engines... (temps went from 165 to 150F as well).

Thank for any info.

Re: 1994 Ford MPI 5.0: ECU in safe mode at low voltage?

So, a trip to my local Ford dealer confirmed that, indeed, in a low voltage situation,
these engines go into EMFM (STrategic) mode where all parameters are fixed
in a very scaled back ranges, which included a very rich mixture to prevent
any detonation.

The tech thinks it's 11.5V that serves as a trigger point...

Re: 1994 Ford MPI 5.0: ECU in safe mode at low voltage?

MasterGoa said:

So, a trip to my local Ford dealer confirmed that, indeed, in a low voltage situation,
these engines go into EMFM (STrategic) mode where all parameters are fixed
in a very scaled back ranges, which included a very rich mixture to prevent
any detonation.

The tech thinks it's 11.5V that serves as a trigger point...

Click to expand...

Very interesting. Thanks for another tidbit of info that I can use if I ever need to in the future. I have the 5.8 FI in my 94 Four Winns Horizon.