Decel Cut-Off
A common fuel saving feature in original equipment computers is a fuel cut-off on
deceleration. This will cut fuel delivery to the engine while coasting down hills with
closed throttle. This feature can be enabled or disabled on the E6K. It is better, when
first tuning, to disable this function.
I misunderstood it - Robert you're correct, below the set RPM decel cut-off doesn't operate, but above that it will come into effect with closed throttle.
My car would not rev because it was incorrectly reading 0% throttle and stopping the engine at anything over 1,500 - as soon as I turned off the function, recalibrated the TPS everything was fine again. So my idle is not effected, I'd just be wasting fuel down hills all the time.
Mark.
On Thursday, August 28, 2003, at 12:07 AM, Robert Charles Scealy wrote:
Are you sure it doesnt cut fuel when you are at 0% and above 1500rpm?
Otherwise with your injectors going to 0ms at 0% throttle and below 1500
the thing wouldnt idle. In this case it wont affect your idle at all,
and at big vacuum above 1500 the injectors will be doing bugger all
anyway.
On Wed, 27 Aug 2003, Mark wrote:
Specifically for the Haltech application the parameters are when 0%
throttle AND the below set RPM (1,500 in my fuel map) - just wondering
what is happening when I disable this function i.e. will it running-on
or run rich when under 1,500 @ 0% throttle when decel cutout function
disabled or just idle rich.
On Wednesday, August 27, 2003, at 11:10 PM, mark krawczuk wrote:
hi, decel cuts fuel of when you , er , um decelerate cause you dont
need
fuel then.
mark k
----- Original Message -----
From: "ryanmel" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, August 27, 2003 7:52 PM
Subject: Re: How free should T03 impeller rotate?
i think decel cut off is mainly for fuel efficiency, may be wrong, butthrottle?
pretty sure
----- Original Message -----
From: "Mark" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, August 27, 2003 5:29 PM
Subject: Re: How free should T03 impeller rotate?
Justin was right on the money - the TPS was playing up, reading 0%
when it shouldn't (I didn't print or save the last datalog otherwise
I
might have noticed this earlier - but it was obvious when reading the
engine data tonight after work on the trusty Toshiba).
I disabled decel cutoff and recalibrated the TPS and woohoo! around
the
block I go and what a relief - I had contemplated $$$ check & rebuild
on the turbo such was my paranoia. Now I wonder what the implications
are of not running with decel cutoff on my motor - pretty well stock
FJ20 Turbo with 2.5" exahust.
Previously when it self-corrected it lead me to look at the turbo -
when in fact it simply must have been repeated rotation of the TPS
which flicked back into life. So now gotta add the laptop to my
emergency tool box anytime I venture more than a few hours walk from
home ;-(
On Wednesday, August 27, 2003, at 04:21 PM, Robert Charles Scealy
wrote:
Just testing a theory, on your old log does it only go to 32 when
you
are above 1700 rpm? Does it only go to 8 when you are off the
toAnd when you are on the throttle at all but under 1700rpm does it go
to0? And are all the occurances of the code 40 happen when you are
both
off the throttle and engine revs are about 1700rpm?
On Wed, 27 Aug 2003 [EMAIL PROTECTED] wrote:
Here's the quote from a Tuner on the Haltech forum, I'm still
awaiting a reply
from Haltech support.
==============================
Hi Mark,
The engine flags reading in the software is really quite difficult
to
dechipher
unless you really know what your looking at and even then they are
of
limited
use. This is really a Haltech in-house debug tool .. wont really
help
you.
It sound like you have the decel cutoff feature catching you out.
Step 1. Make sure your TPS is connected and correctly calibrated...
Best to recalibrate it to be sure ... very easy ... go to Menu and
select
calibrate throttle and do what it tells you to do.
Step 2.
Go to the Fuel setup page and see if "decel cutoff" in enabled or
disabled.
My bet is that decel cutoff is enabled at 1700 rpm and that is what
is going
on .... Decel cutoff will cut fuel at the set RPM when ever the
engine is above
the setpoint and at zero tps.
It will cut back in if you come back below set RPM or if throttle
exceeds 1%
Best thing to is to turn it off ... do your tuning ... and then
re-activate it
if you want to use it .. some engines are better off without it
(ported
rotaries for example)
I hope that helps
Regards
Justin K
Tweakit Performance
Sydney Australia
==========================
Quoting Robert Charles Scealy <[EMAIL PROTECTED]>:
I find it interesting that they say it is a debug flag, and that
32
+ 8
= 40. It sounds to me like value 32 and value 8 are not supposed
to
occur together. Do you have the exact wording of what the Haltech
board
said about these flags?
The only time I have ever spun turbos I would say I have been able
itflick them hard enough to maybe a couple of revolutions.
On Wed, 27 Aug 2003 [EMAIL PROTECTED] wrote:
Trying to diagnose my FJ20ET F9 ECU that cuts out at ~1700 rpm -thought
I
maybe turbo was not healthy and removed the filter and intakecan
piping - I
rotate the compressor impeller quite easily - I don't expect that
32.should
just spin almost without friction or should it?of
I ran a datalog on a laptop and the printout shows that at the
precise time
cutout (or surging if I maintain a steady throttle at aroundand
1,700
rpm)
the "engine flag" value changes from 8 to 40 and inj m/sec goes
to
0.000.
Advice from the Haltech board is the flags are an "in house debug
tool"
hard to decipher.40
Examining an older log when engine ran fine I do see an
occasional
value of
with inj m/sec 0.0000, but only rarely. Mostly it reads 0, 8, or
Also suggested was to disable decel cut-off and recalibrate thewhich
TPS
both
I'll try tonight after work.
Mark.JT
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