2006 Honda Civic DX-G Throttle-by-wire

I got a manual transmission 2006 Civic DX-G at the end of May, and have
since put on over 10500 Km. During that time, I have averaged 6.87
Litres/100 Km on the whole 10500 Km, 5.71 on a 3000 Km road trip and as
low as 5.24 on some sections of the road trip. So I certainly have no
problems with the gas mileage.

However, since I first got the car the throttle has produced a slight
jump between acceleration and deceleration (feels like an automatic
transmission shifting), rather than the smooth ability to set a speed
that I have been used to on other cars (all non-Honda).

You notice this the most trying to maintain a steady speed on downhill
sections. Backing off on the throttle slightly to maintain speed results
in a slight notching of the engine into engine braking. As the speed
drops, a slight increase in the throttle, to maintain speed, results in
a slight jump in the engine, and the speed rises too high. There appears
to be a small area of the travel of the throttle so that slight changes
in the throttle position do not change the engine speed, at a constant
load, but moving past this point will jump the power up or down (sort of
like a point of histerysis in the power curve).

During the road trip I noticed that it was difficult to maintain speed
as terrain changed, and slight changes in slope, insufficient to require
engine braking to hold speed down, could have significant changes in
road speed, if you were not continually watching the speedometer, in the
range of more than + or minus 10 Km per hour at a road speed of around
100 Km per hour. This required a higher driver attention load to stay
around the speed I wanted to be going. I saw a lot less of the scenery
than I would have in any other car I have had.

The questions I raise are:

1. Should the throttle have this "shifting" effect, or should it be a
smooth transition of more or less power.

2. Should the car speed range through such a wide range without constant
attention, with slope changes small enough to not really be noticable to
the driver?

And if this effect is not normal, what could be done about it. I have
already mentioned this to the dealer, who had it road tested, and
indicated that it was normal for a manual transmission.

Tom

 

this behavior is mostly normal and not unique to honda. i had the same
on a rental toyota recently, and it's a pita. but here's the deal:
modern cars are set to run for maximum economy. that means shutting off
fuel delivery entirely when coasting above a minimum speed. if you're
only just coasting, you're going to be on the edge of the
coast/not-coast logic control in the ecu, hence the on/off fuel delivery
you're experiencing. short of reverting to an old-school honda, i don't
believe there's much you can do about it. it may be that there's a
software upgrade available for your car, so check with your dealer, but
if it's not on the bug list, it won't be fixed. the way to get it onto
the bug list is to keep taking it back to the dealer.

 

Thanks for the information. I will probably pursue it a bit more, but
other than this the car has been fine (a few minor fit and finish glitches).

Tom

 

Doesn't sound normal to me. I certainly have not noticed such effects in
my 06 Civic Si... Perhaps take the tech with you for a ride, and point
out what you are talking about when it happens...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 10/2/2006 3:21:09 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/
I don't have all the answers. I haven't yet heard all the questions...

 

That actually makes sense, and wouldn't be noticed on the Si, due to the
lower considerations for fuel economy...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 10/2/2006 3:22:44 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

Man is the best computer we can put aboard a spacecraft ... and the only
one that can be mass produced with unskilled labor.
--Wernher von Braun