Ford and Volkswagen MPV Forums

Large MPVs -- Ford Galaxy / VW Sharan / SEAT Alhambra: => Ford Galaxy / VW Sharan / SEAT Alhambra => Topic started by: dbn on November 29, 2012, 09:25:46 AM

Title: Deceleration fuel-cut-off RPMs too high!
Post by: dbn on November 29, 2012, 09:25:46 AM
Hi,

Can anyone answer me what SHOULD be the DFSO (DECEL FUEL SHUT OFF) criterion and RPM threshold for my 1998 Galaxy 2.3i according to FORD specification?

My car enters DFSO mode (fuel injection time = 0) at about 3600 rpm and leaves DFSO (fuel injection time > 1 msec) at about 3500 rpm.

Thanks a lot in advance!


Follow some details.

I'm driving this car for 12 months and engine appears to be in almost perfect condition (except DFSO).
I've examined few other Galaxy Mk1 and they ALL enter DFSO at 3500-3600 rpm. I know for an Ford Focus with the same issue. I don't know if all Fords do the same.

Few people already told me FORD used to set DFSO-RPMs too high (as I see by myself).
But that's ridiculous! I don't want to believe FORD intentionally did it, virtually preventing millions of cars from possibility to obtain useful engine-braking effect when driving downhill! Missing DFSO when driving down from a mountain, especially on snowy and icy terrain is really a safety issue!
So I'd like to see the actual  DFSO settings in FORD specification for my car...
BTW, finally I consider building and installing a separate DFSO system.

DFSO likely is more often known as DFCO (deceleration fuel-cut-off), but in a Ford strategy book I found they used DFSO. That book however was too common and there where no numbers for rpm, temp etc...

I was driving another, much elder car (not Ford) and it used to enter DFSO/DFCO at about 1500-2500 rpm depending on temperature etc. As I know some other cars can enter DFSO/DFCO as early as at 1100-1200 rpm. I don't know for what reason Ford could have decided to set DFSO threshold to 3500-3600 rpm...
Title: Re: Deceleration fuel-cut-off RPMs too high!
Post by: dbn on November 29, 2012, 09:39:22 AM
Missing DFSO when driving down from a mountain, especially on snowy and icy terrain is really a safety issue!
P.S. I just wanted to emphasize why I'm so worried about DFSO issue but found no option to edit the post.
Title: Re: Deceleration fuel-cut-off RPMs too high!
Post by: Mirez on November 29, 2012, 05:14:43 PM
Hi and welcome to the forum - a nice juicy technical question eh!

The 2.3 in the Galaxy is the same engine used in the Scorpio and Transit so you may find a little more info digging around on those forums for the exact figure however in essence I believe it IS intentionally high on the 2.3 - this is primarily because of the extra mass from the 2.3 pistons generating a significant secondary force during crank rotation. Allowing the engine to enter DFSO earlier would create excess vibration and noise as a result which wouldn't have suited the luxury market this engine was targeted at at concept.

I seem to remember reading something about this a long time back when escort owners were trying to wedge the engine in their bay - I'll have a further rummage later.
Title: Re: Deceleration fuel-cut-off RPMs too high!
Post by: dbn on December 01, 2012, 08:45:49 PM
Hi,
I did a test-drive in a friend's Galaxy 2.0i Mk1 with self-made DFSO-system and there were no such vibrations so I think that's not about luxury...
P.S. Actually I do not know any unmodified Galaxy Mk1 fitted with Ford engine, i.e. 2.3i and 2.0i to enter DFSO below 3500 rpm.