Date: Fri, 18 May 2001 07:33:15 -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
Hi Mike,
Ok, I read through your response. It appears to me that the mechanic may
be trying to "adjust" or troubleshoot this problem in closed loop mode,
i.e. the O2 sensor is connected to the ECU. The adjustments or trouble
shooting needs to be done open loop, otherwise you can't observe the
base ECU output, since the O2 sensor gives feedback so the computer can
try an adjust the mixture. All readings are pre-cat that I gave you.
BTW even though you say your not a mechanic, you seem mechanically
inclined enough to do this. Having a digitool makes this just about a
one allen wrench/screwdriver job. Disconnect the O2 and drive, adjust,
drive, adjust. The high fuel pressure is just an idle thing in most
cases it's the AFM spring tension first that will kill you-- do it first.
Get the mechanic to give you a Idle 880 rpm vacuum reading. mine is 13"
I'd say 11 is minimum.
Then there are two screws to adjust. The big slotted one is really for
IDLE SPEED with the idle stabilizer connected. The other screw is the
AFM CO adjustment. This really just adjust the position of the AFM flap
at idle by allowing more or less air to "bypass". By adjusting the flaps
position your really adjusting the computers basic input to idle
mixture, since the flap is connected to the wiper arm.
As to you mechanic test results/ procedures. The Bentley states that the
engine must have cycled the cooling fan at least once before "checking
the basic gas output. Past that your idle hc, unburned fuel 1300+
appears to 8- 10 x too high. The other readings look way off to me. A
fuel injected car should be able to keep HC below 220 is limit, 100 is
probably a good benchmark. CO is 5%. The Bosch digifant can do this
easily without an O2 connected. As I said the O2 voltage correlates
with CO. so a .5 volt Digitool at idle is approx. 5% CO.
I think the cam is getting a bad rap from your mechanics. I'd ignore it
until every thing else has been done. But to be fair cam lope, is
somewhat similar to chugging from an over rich mixture.
If it were me, I'd ask the mechanics to try getting the #3 compression
up as in valve adjustment, get the vacuum question answered, if it's
low, have them verify the timing is right. A mechanic can tell if the
vacuum is low because of a hose leak, intake leak, etc. As for my
pressure regulator, I'd send it for shipping costs if all else fails,
but you have a few things to verify first.
r
Sincerely,
Mark Keller
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