Date: Wed, 16 May 2001 22:10:32 -0800
Reply-To: Mark Keller <kelphoto@islandnet.com>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Keller <kelphoto@islandnet.com>
Subject: Re: Fuel Injection
Content-Type: text/plain; charset=us-ascii
Mike,
Well, if your low on the #3 cylinder that may would have to be worked
out first. If you said 4 lbs high, as in 29 + 4 = 33 lbs at idle with
the vacuum hose connected and your getting around 12 inches of vacuum
you have a problem with the pressure regulator as that's over half of
the range. 29- 36 is operating range of high to low load or vacuum --
not a tolerance. If you have 36 + 4 =40 lbs at the above conditions you
have a bigger problem with the pressure regulator.
I don't mean to sound harsh, but I believe that 4 psi at idle is enough
to put your HC up. Mine run at 50 ppm HC on the lean side but ok. The
other thing is you don't mention attempting to adjust the idle air
bypass, aka CO adjustment. This could also be out of adjustment. Most
people myself include use the O2 sensor output voltage to set CO since
there is nearly a exact correlation i.e. .5 volts =5% CO etc.-- this tip
is in the Bosch Fuel injection Book by Probst. And it really matters
what vacuum your getting at idle. BTW I have a spare fuel pressure
regulator for what it's worth you can try it out.
Also while were here, the first thing that should be done is to set the
spring tension or verify it by looking for an O2 sensor output reading
in the .5 volts- .7 volts range while the engine is at 3000 rpm. This
is also covered recently, but its' mainly moving the geared wheel under
the afm cover. Once the spring tension is right, check the settings.
BTW, the O2 sensor is disconnect from the computer in these scenarios.
I've had the 4 gas analyzer done too, but using an O2 is probably is
just as good.
You didn't mention if you had read the posts I referred to. Lilley is
the one who stated that High HC at idle in his own van caused him to
fail emission as was due to high fuel pressure because of a cracked
vacuum line not the cam as you suggest.
If your engine is warm the idle stabilizer in not operation, it only for
cold engine warm up. The idle stabilizer in fact adjusted by
disconnecting it, and then adjusting the idle manually.
I wrote this kinda quick, so email me if something is unclear.
Sincerely,
Mark
Mike Finkbiner wrote:
>
> Mark -
>
> It's an interesting problem, and probably has several components. The
> engine is still tight, and #3 cylinder is reading only 110 psi, so we
> probably need to adjust the valves, but the rhythmic surging at steady
> speeds really puzzles me.
>
> The high HC at idle is probably from the longer duration cam that Bob put
> in. This engine has the ported and polished heads with the Lilly cam that
> is supposed to provide more grunt without sacrificing reliability. It will
> be nice if that turns out to be true!
>
> The mechanic who ran the emissions tests said they looked good other than
> that. There is currently no cat in the system.
>
> Another listee suggested disconnecting the idle stabilizer temporarily. I
> also have a new Temp II sensor. They will be a lot cheaper to check than
> ordering a new fuel pressure regulator.
>
> Current plan is to disconnect the idle stabilizer before I take a 100 mile
> drive on Saturday, then check the valves early next week, and replace the
> Temp II.
>
> In a situation like this, it would be so nice to have a collection of
> known-good used parts to plug in, and see what the result is!
>
> Any suggestions gratefully accepted!
>
> - Mike
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