Date: Sun, 30 Dec 2001 21:40:22 -1000
Reply-To: Ed Sato <edsato@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ed Sato <edsato@JUNO.COM>
Subject: Re: Understanding AFC fuel injection--question
Content-Type: text/plain; charset=us-ascii
. What I do not get is the process when it is starting cold.....air
flows thru the AFM, and if the motor is cold enough, the auxillary air
regulator is open, and air is diverted to the intake manifold, thus
bypassing the throttle body. This book says that this enables the motor
to act the same cold as it does hot, for the control unit adds additional
fuel to the injectors when it senses the engine is cold. Now, there is
no sensor, or anything on the throttle body, so how does this auxillary
air regulator do anything?
Adam
I am not an expert on this subject. But from what I see....on cold start
most engines have a step throttle stop on the carburetor to increase the
idle speed for warm up purposes. The vanagon does not. So it instead has
sensors that distribute extra air and gas that bypasses the throttle
plate so that higher idle speed can be obtained for warm up. I notice
that it is not the same as other cars in that you do not need to step on
the pedal to bring the idle back to normal. But then again other problems
may occur when this type of system is not operating correctly. Importance
here make sure all sensors are good. I too have problems with bad fuel
mileage. So far replaced plugs, filters, O2, T II with no change. I used
to have 19 -20 mpg. Went down to 18 then 16 until recently 14mpg. Started
replacing above when it hit 14. The last thing I replaced was my fuel
pressure regulator. It did not seem to be bad but I figured since my van
has 200,000 miles it will go bad anyway. Plus the fact that Ken had that
great price for it (Thank you Ken Wilfy!). I also did not have a fuel
pressure gauge. What I did notice after changing it. First after removing
it I tried to see if there was any difference in back pressure. No gauges
used the old fashioned pressure by mouth. The new one held pressure, the
old one also held pressure but detected some leakage. It was here that I
had second thoughts about this being the cure to my problem. After
changing it I feel that this may have been the problem all along. Van
drives alot better below 3000 rpms. I haven't checked my mpg yet but will
report back if anyone is interested. Another thing that I did notice
which may not have any bearing to the changing the FPR is that I used to
have the same hot start problems that most of the lists were mentioning.
It just dissappeared which kinda makes sense to me now but being that
everyone has their own opinions. I leave it up to your own imaginations.
Hope this helps you Adam. If not well Have a Happy New Year anyway!
Aloha, Ed
P.S. To all of you other Vanagoners out there. I have learned alot about
the fuel injection system through your bickering , rantings and ravings
and of yeah down to earth helpfullness. I would like to thank you all too
and wish you all a Happy New Year!
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