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Date:         Sat, 24 Aug 2002 23:23:37 -0700
Reply-To:     Steven Dodson <steven@EPOCHDESIGN.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Steven Dodson <steven@EPOCHDESIGN.COM>
Subject:      Re: Not passing smog, still... Need help!
In-Reply-To:  <5.1.0.14.0.20020824190724.03aa8d90@pop3.rockisland.com>
Content-Type: text/plain; charset="us-ascii"

I am greatly appreciative of all of you, for your help!

It is difficult sometimes to decipher between conflicting views or diagnosis. One thing stands for certain, my (ex)mechanic isn't interested and/or skilled enough to do a good job. I also think that he may have checked one cylinder (if any) and blown the rest off.

Tim, I am able to get and even keep the open loop voltage below .5V (or .01V for that matter), it just floats around too much when I try to set it in the zone. I do agree that #4 is trouble and may be the cause of my problems. I checked under and around and I couldn't find ANY hoses going into any fitting on or near the top of my air filter. Are there any systems that may be different? I'll look again.

Dennis, I have pressurized #4 for 15 minutes with only 1-2psi of loss at ~100psi to start. Doesn't seem like much loss. Wouldn't the ECU's attempt to compensate just run the value up to the closest reading and not fluctuate wildly? I ask because I don't know. You are right about an extension being my best bet. I just find it hard to put the issue to bed without fight.

Matt, After careful examination of maintenance invoices of the DPO, I did find out that this sensor was installed roughly 60K miles ago. It should be replaced. However, when I talked to the kind folks at VolksCafe, they said the readings I was getting off the sensor were similar to one nearly new.

Mark, I will try your valve adjustment test and see what happens.

In the mean-time, I'm running MMO to see if that does anything. If I can't get any improved results in the next 48 hours and unless I can just get an extension for a year, will be spending lots of time on hold with BAR to discuss the problem and get a referee appointment.

Thanks again everyone for your help and endurance! Any final words of wisdom are welcome.

-Steven Dodson Kneeland, CA "Inga" the 87 Syncro

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf Of Doktor Tim Sent: Saturday, August 24, 2002 7:27 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Not passing smog, still... Need help!

I strongly suspect that weak cylinder is putting off enough unburned hydrocarbons that the mean effect is you are out of the range of adjustment for the system. What is the min spec for compression?? About 102 if memory serves. You certainly are out of spec for total difference between cylinders. This creates a situation where the oxy is reading an average of 3 lean cylinders and 1 rich, resulting in the oxy sending false data to the ECU. The fact that you cannot get open loop below 0.5v verifies the weakness is beyond the operating parameters of the system.

Now, if your mechanic was aware of the compression imbalance and didn't recognize that as an issue of high concern, he has not the knowledge to be servicing Bosch systems. Moreover, if he didn't do a compression test very early in his analysis, he is incompetent to do diagnostic work. I don't care if his wall is full of certifications, his actions are definitive in this regard.

This is why proper procedure requires you verify mechanicals first. If that's out of spec and you don't know it, you can futz with it till hell freezes over and never get spec tune. Mechanics who don't follow proper procedures are a bane to society.

The charcoal hose should be a clear (yellow with age) vinyl hose entering the motor compartment at the right upper front and running directly to the upper air filter cover. It fits on a round fitting, about 12mm diameter, and originally was clamped with a permanent squeeze ear type clamp.

At 06:41 PM 08/24/2002, you wrote:

>Doktor Tim, > >The compression is (in cyl order) 130, 128, 132, 98-100 (most likely rings). >Fuel pressure is good per test I watched the mechanic perform. > I couldn't find the Charcoal hose going to my air filter.


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