Date: Sun, 16 Sep 2007 12:51:05 -0700
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: Rich on side, lean the other?
In-Reply-To: <46ED7A94.2040302@verizon.net>
Content-Type: text/plain; charset="US-ASCII"
The injectors are down at the end of 11 inch long intake runners,
So unless fuel is going to go backwards upstream against flowing air, fuel
will not get to all 4 cylinders if one injector is disabled.
In general, I think TBI ( throttle body injection ) is less efficient, like
fuel can puddle or drop out of its atomomized state mixed in with air before
it gets to the cylinders.
For sure you can swap injector wires on one side and it will make no
difference. They are not sequential, the operate together, all 4 injectors.
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mike Collum
Sent: Sunday, September 16, 2007 11:49 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Rich on side, lean the other?
I don't know why they didn't use throttle body injection.
If you unplug one injector it will run on 3 cylinders. I had a broken
wire on my #3 not long ago so I know that to be true.
You can swap the injector plugs and notice no difference in the running.
Mike
Raymond Paquette wrote:
> Mike
>
> I don't doubt that you know what you're talking about, but that seems
> bizarre. Why then is there an injector at each cylinder, instead of one
big
> one in the throttle body? Faster response? Why not more than one per
> cylinder, or one on each bank?
>
> So, if I were to disconnect one injector, the engine would continue to run
> on all 4 cylinders, but will simply run lean? slower? with less power?
>
> Ray
>
> On 9/16/07, Mike Collum <collum@verizon.net> wrote:
>> 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
>>>>
>
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