Date: Wed, 25 Jun 2014 20:25:16 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: Inconsistent stumbling on resume throttle..Was "vanagon
syndrome?"
In-Reply-To: <A4EEC7BB-D861-4203-B868-F2670A90DA73@comcast.net>
Content-Type: text/plain; charset=UTF-8
You are right, yes I do need to fix my exhaust system leak.
If it were a giant big crack, it would be more critical. It's a tiny
leak that you can just hear, sort of, and hear better if you stick a
listening tube up near the flange where the downpipes connect to the dual
outlet exhaust manifold...It just happens to be a small crack in the flex
joint of the primary exhaust tube that does NOT have the O2 sensor in
it...but I don't think that matters much..... And yes, the O2 sensor would
do better if it got a reading from all four cylinders rather than just two,
like it does. But there is no room for it anywhere else in the system.
The primaries are 'best performance' at 32" before they merge, according to
testing by Techtonic's Tuning....so mine go around, individual primary
tubes, to the rear bumper and across toward the passenger side, then they
merge and enter the muffler and then...done...end of system...
I could put two O2 sensors in there, but then I'd have to figure out how
to integrate the readings into the computer....This is a Vanagon...probably
around 135hp in a 4000lb vehicle...it works good enough for me like it
is...
I doubt that the O2 sensor is reading a lean mixture from this tiny
leak...maybe it's a tiny insignificant amount off... but when it was all
wire-connected I was getting ~23+mpg so it was not running " flooded "
You are right...I have some 'issues' that could/should be rectified... In
a perfect world I'd just send the Vanagon over to the shop and say "Fix
it right and bring it back when you are done"... But this isn't a perfect
world...and I want to go windsurfing tomorrow.... because it's supposed to
blow into the 50mph range and I don't have another vehicle that works as
well as my Vanagon for that...so the exhaust leak and the poorly-placed O2
sensor will just have to wait.....again... grin!
Thanks, I'll get around to it sometime pretty soon, I am sure....the
leak, for certain... If you want a look at what I am talking about you may
be able to follow this link (paste it maybe) to my google pics of when I
was doing the revision for the ABA block.
https://plus.google.com/photos/112899774170781374478/albums/5527276583316353665?authkey=CP7hiandmfaB-wE
Don Hanson
On Wed, Jun 25, 2014 at 6:37 PM, OlRivrRat <OlRivrRat@comcast.net> wrote:
> Don
>
> So just to be ReallyClear on this ~ "upstream of the O2 sensor" ~
> So the crack is
>
> between the Eng' & The O2Snsr ~ If this is indeed the Case it is NOT a
> good thing for
>
> your Eng's Performance or your O2Snsr ~ RawAir is MostLikely being pulled
> through the
>
> crack into the Pipe & Causing the O2Snsr to think it is being exposed to
> LeanExhaust so
>
> the ECU would then dump gas into the Mix to compensate & when you back off
> the Gas
>
> it is conceivable that an ExtraShot of RawAir might get sucked in through
> the Crack &So
>
> when you get back on the Gas a very Rich, maybe even FloodedCondition, is
> occurring @
>
> which point the ECU just says ~ OK this is Goofy, I need a short break ~
>
> The Iffy Wires may indeed be contributing to the Issue but
>
> ~~~~~~~ YouReally NeedToFix ThatCrack ~~~~~~~
>
> & ~ Your O2Snsr should not be in 1 of your HeaderTubes ~ It should
> be located after
>
> the Collector so that It "Sees" the Exhaust from All4 Cyl's ~
>
>
> ORR ~ DeanB
>
>
>
| 
