Date: Sun, 16 Sep 2007 08:38:50 -0400
Reply-To: Mike Collum <collum@VERIZON.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike Collum <collum@VERIZON.NET>
Subject: Re: Rich on side, lean the other?
In-Reply-To: <5d903de80709160509t18f906fsaf6be202f7681b27@mail.gmail.com>
Content-type: text/plain; charset=ISO-8859-1; format=flowed
VW wasserboxers do indeed fire all injectors at once ... unlike the
Subaru engines which fire them sequentially.
Think of the wasserboxer as being similar to a carburetted engine where
there is no sequential input of fuel. The fuel is simply available when
the intake valves open.
Mike
Raymond Paquette wrote:
> Scott
>
> Can you explain this? It would seem to me that if the injectors all fires
> at once, then three cylinders would get gas when they weren't meant to be
> firing.
>
> What am I missing?
>
> Ray
>
> On 9/16/07, Scott Daniel - Shazam <scottdaniel@turbovans.com> wrote:
>> The ECU can't run any injectors richer than any others.
>> It fires the 4 injectors at once, by supplying ground to them.
>> It treats the injectors as one big injector in 4 parts.
>> The Oxygen sensor is a good thought - it's very easy to measure their
>> output
>> with a digital voltmeter. If it's been on there several years, it could be
>> due anyway.
>>
>> I can't think of why one side would run rich and the other learner.
>> You could swap the injectors side to side and see if the problem follows
>> the
>> injectors, or stays in the same place.
>> You could observe the spray pattern in accordance with the Bentley manual
>> too.
>> Scott
>> www.turbovans.com
>>
>>
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
>> Michael Elliott
>> Sent: Saturday, September 15, 2007 4:59 PM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: Rich on side, lean the other?
>>
>> I'm hunting for the reason that Mellow Yellow gets about 15% poorer
>> mileage than other similar vans. See
>>
>> http://camping.elliott.googlepages.com/poormileage
>>
>> to see what I've learned so far about this 1.9L 1984 auto transmission
>> with only 75,000 miles on it.
>>
>> One oddness I've found is that both plugs on the passenger side indicate
>> lean condition, while the plugs on driver's side indicate rich condition.
>> Where could such an asymmetry come from?
>>
>> There are NO visible signs of air leaks. The intake runners don't have any
>> cracks, are tightened well against heads; the plenum/runner sleeves are
>> clean and intact; and there are NO cracks in the exhaust bits that might
>> cause a false-lean reading at the O2 sensor -- this is a southern
>> California car and we outlawed snow and salt in 1932.
>>
>> This lateral mixture imbalance has me quite puzzled. I am getting little
>> fret marks between my eyebrows! I'm dumping in a buttload of Techron
>> injector cleaner in case the injectors on the lean side are packed up and
>> the ECU is overcompensating by running #3 and #4 rich.
>>
>> But . . . and but, the overall mix at the O2 sensor indicates /lean/ on
>> the highway, oddly (see http://camping.elliott.googlepages.com/poormileage
>> ).
>>
>> I am replacing the O2 sensor on Monday. Because.
>>
>> --
>> Mike "Rocket J Squirrel" Elliott
>> 71 Type 2: the Wonderbus
>> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
>> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
>> KG6RCR
>>
>
|