Date:         Wed, 14 May 2003 03:04:59 -0700
Reply-To:     zampano <matthias.k@ATTBI.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         zampano <matthias.k@ATTBI.COM>
Subject:      Fwd: Vgon syndrome on 1.9 WBX
Content-Type: text/plain; charset=US-ASCII; format=flowed

> From: zampano <matthias.k@attbi.com>
> Date: Wed May 14, 2003  3:03:06 am US/Pacific
> To: "John McMahon" <jfm@nts-online.net>
> Subject: Re: Vgon syndrome on 1.9 WBX
>
> Hi John, evrybody
>
> Anything like tire pressure and brakes binding etc can be ruled out.
>
> I know that on CIS injectioned engines there's a separate injector
> just for warm up. The Digijet just has an auxiliary air valve which
> pumps air into the intake. Or might I be wrong?? Is it an actuall
> injector?? But there's no fuel line going to it.
> If I squeeze that hose from past the AFM to this valve at idle, the
> idle drops. Since she idles really poorly, I don't know for sure
> though.
> That aux air valve is really hard to get to. I'll try and disconnect
> it and see what happens.
>
> Cheers
>
> m
> On Tuesday, May 13, 2003, at 11:33  PM, John McMahon wrote:
>
>> Matthias,
>> Thanks for the rapid reply.  What about the Cold Start Valve?  Does
>> the
>> Digijet system have a Thermo-Time Switch?  In my 1975 VW Beetle with
>> L-Jetronic (AFC),
>> I once had a injector stick wide open dumping raw fuel out of the
>> tail pipe.
>> Since I believe that the orifice on the Cold Start is likely to be
>> smaller
>> than on an injector, it could be that you have a Cold Start Valve
>> that isn't
>> shutting off, or the needle can't/won't seat properly and you are
>> leaking
>> fuel continuously.  That might explain the
>> rough idle when warm.  The Thermo-Time switch could be faulty or the
>> wiring
>> harness shorted/crimped/pinched telling the Cold Start Valve to spray
>> constantly.
>> I am leaning away from ignition, and toward fuel system.
>> My other thought: a combination of "problems", maybe?
>> Front-end misalignment, low tire pressure, wrong tire/wheel size,
>> overloading, a/c usage, dragging brakes, clutch? slippage, all
>> contributing
>> for the increase in fuel consumption.
>> Good luck...you'll find it!
>> John M
>> ----- Original Message -----
>> From: "zampano" <matthias.k@attbi.com>
>> To: "John McMahon" <jfm@nts-online.net>
>> Cc: <vanagon@GERRY.VANAGON.COM>
>> Sent: Wednesday, May 14, 2003 12:18 AM
>> Subject: Re: Vgon syndrome on 1.9 WBX
>>
>>
>>> ok you guys,
>>>
>>> The spark plugs I just changed as well. They were beyond fouled, no
>>> surprise at 8 mpg. There is no fuel leaking anywhere visible. The
>>> possibility of the exhaust being blocked seems ruled out, since I
>>> removed the cat altogether, and the muffler seems fine, as in: I can
>>> blow air thru it if I blow real hard. . Easy now. Seriously, I got
>>> the
>>> muzzie to prove it. It's maybe 2 years old as well.  I had the
>>> J-exhaust pipe replaced at a shop, and the trip home (80+ miles) went
>>> fine. Although I only got 15 mpg.
>>> I did all the resistance/continuity checks in the Bentley, in the
>>> fuel
>>> injection group, they all checked out fine. Even did all the checks
>>> involving the throttle valve/full throttle enrichment valve. Check.
>>> My
>>> air filter is rather clean. Fresh spark plugs now. New OXSensor from
>>> ShmAutozone. Resistance is fine on my spark plug / ignition wires.
>>> Coil
>>> checks out ok. My injectors spray in nice cone fashion. Checked
>>> resistance on Hall sender, fine. Only things I can think of is the
>>> AFM
>>> and the ignition distributor, or maybe the ignition distributor.
>>> Have
>>> not checked fuel pressure regulator reliably, but it is maybe 2 years
>>> old, as is fuel pump. Fuel filter is 3 years old. Fuel delivery is
>>> according to spec (Bentley). Timing seemed fine, although maybe a bit
>>> jumpy, to the tune of 1-2 degrees maybe. All vacuum hoses are
>>> connected
>>> and tight, heck, they have mostly been replaced when they put my
>>> motor
>>> back together under warranty.
>>> Maybe my cold start auxiliary valve is shot, but all the test per
>>> Bentley worked out, though she idles real poorly.
>>> Have not done a compression test yet. Have not been able to really
>>> check AFM, though I did all the checks in the Bentley, and the
>>> results
>>> are spot on. (But what is the tolerance when I move the flap, Bentley
>>> and Haynes are rather unspecific...). All my grounds are wired
>>> afresh,
>>> and they contact the motor (rebuilt 2 months ago) outstandingly, I
>>> should think. It seems insane that I should be getting 8 mpg.
>>>
>>> I bet the farm it's got to be my AFM. It;s been my daily driver for
>>> the
>>> last three months, and the bad fuel economy only started 1 month ago
>>> (15-16 mpg city/mixed).
>>>
>>> If anybody knows of an accurate way to test the AFM while moving the
>>> flap, let me know, please.
>>> It idles poorly once it's warm, and dies at times, stays around
>>> 400-600
>>> rpms when warm, normal (900 rpms) when cold.
>>> I can smell that the exhaust is too rich.
>>>
>>> Why am I doing this to myself???
>>>
>>>
>>> Cheers
>>>
>>> m
>>> On Tuesday, May 13, 2003, at 09:30  PM, John McMahon wrote:
>>>
>>>> Matthias,
>>>> Has there been a noticeable change in the idle speed, or idle
>>>> smoothness?
>>>> Do the spark plugs appear black, sooty, fouled, wet?  Accelerator
>>>> pedal seem
>>>> to be in the same position per mph?
>>>> I am supposing that you've checked the cleanliness of the air
>>>> filter.
>>>> I am guessing here, but it seems that it has to be enrichment
>>>> related.
>>>> However, without other symptoms
>>>> showing themselves, that doesn't make complete sense.
>>>> If your calculations are correct, and you are not leaking it
>>>> somewhere, the
>>>> spent fuel has to be going out the tail pipe one way or another.
>>>> An interesting problem.  I will be watching for the answer.
>>>> Good luck!
>>>> John McMahon
>>>> Abilene, Texas
>>>>
>>>> ----- Original Message -----
>>>> From: "zampano" <matthias.k@ATTBI.COM>
>>>> To: <vanagon@GERRY.VANAGON.COM>
>>>> Sent: Tuesday, May 13, 2003 10:07 PM
>>>> Subject: Vgon syndrome on 1.9 WBX
>>>>
>>>>
>>>>> Hi all,
>>>>>
>>>>> So,
>>>>>
>>>>> I checked all the FI sensors and other peripherals. The idle valve,
>>>>> full throttle enrichment
>>>>>                                                         switch,
>>>>> checked
>>>>> all the voltages and resistance per Bentley. All checked out good.
>>>>> Checked the ignition timing. Swapped out the ECU, removed the
>>>>> catalytic
>>>>> converter.
>>>>> All didn't make a difference. I just filled her up and calculated
>>>>> I'm
>>>>> getting 8 mpg. This NEVER happened. Seems insane. Maybe she's
>>>>> starting
>>>>> to behave like her possible Detroit replacement.
>>>>>
>>>>> I am going to order a new AFM from Busdepot. Seems like a  very
>>>>> good
>>>>> deal actually.
>>>>>
>>>>> It's the only thing I can see being bad, though I can't tell for
>>>>> sure
>>>>> that my AFM is bad. The spec in both Bentley and Haynes don't
>>>>> specify
>>>>> exactly whereabouts the resistance would be if you move the flap.
>>>>> It
>>>>> just says" varying voltage", but no more. As I move it around I get
>>>>> fluctuations between 1100 and 1600 ohms, but it doesn't steadily
>>>>> increase in either one direction. While it idles, the potentiometer
>>>>> arm
>>>>> vibrates, when I open the throttle, it gets steady again.
>>>>>
>>>>> I'll keep you all posted on what happens, hopefully the new AFM
>>>>> will
>>>>> make a difference.
>>>>>
>>>>> Happy Trails
>>>>>
>>>>> matthias
>>>>>
>>>>
>>>
>>>
>>
>