Date: Sun, 7 Sep 2003 17:21:22 -0700
Reply-To: Robert Keezer <warmerwagen@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Keezer <warmerwagen@HOTMAIL.COM>
Subject: Re: 87 AFM Cold wthr prblm (long)
Content-Type: text/plain; format=flowed
If there was a way possible to attach a crankshaft position sensor to a WBX
engine then you could do away with the AFM , enjoy driving more than
troubleshooting, by switching the fuel injection system to Motronic.
The WBX is being adapted to become a air-cooled engine- why not a better
fuel injection system?
Motronic is the FI system that controls the '93- and later VW's and uses a
hot-wire air mass sensor(MAF)
instead of a vane type. The MAF has no moving parts.
When you press the accellerator, the greater volume of air going thru the
MAF cools the wire .
The computer measures the changing resistance and sends the signal to the
ECU.
The AFM has moving parts and is now considered old technology. Modern gas
VW's all use hotwire MAF technology.
The main obstacle to switching is the crankshaft position sensor.(CPS)
A knock sensor is another ECU input that has to be accomodated .
It would not be difficult to tap the case for a knock sensor. It may even be
possible to mount the CPS on the flywheel or crank pulley.
On the '93 -later Motonic engines there is a ring on the crank inside the
block. This ring has cut-outs that pass and externally mounted pick-up.
A small electric current is developed and TDC signals sent to the ECU.
The distributor trigger wheel would have to be modified or replaced to have
only one cut-out.
The distributor then serves as another input to the ECU- a camshaft position
sensor.
Now Motronic is really a cool system- It "learns" your driving city or
highway driving habits and adjusts to them.
Motronic also stores fault codes that can be read by a indicator light or
with a laptop computer or shop equipment.
I think it will be much easier to just swapyour WBX out to a '93-later VW
inline four, the ABA 2.0 rated at 115 hp.
I have this engine in my Westfalia and I'm almost finished with my upgrade
to Motronic.
I have been using Golf-Jetta Digifant 2 since 1995 . In 1999, I replaced the
'91 1.8 with a '95 2 liter, but failed to recognize the virtue of the
Motronic FI at the time.
The 2 liter ABA has more power than a WBX and I think it's a happy medium ,
practical and economic.
It fits under the lid with the Diesel mounting system.
Having concluded that my 8 months of reoccuring drivability problems was the
AFM-I decided to upgrade to Motronic.
Troubleshooting has just got a lot easier. Motronic up to 1995 fault codes
can be read by inserting a special jumper plug itno the Data Link Connector
(DLC).
A chart with the codes is all you need to read them, which are displayed in
groups of four flashes.
If all is OK, the code 4-4-4-4 will display. This is only for Motronic up
to 1995. (96- 99 in software only ).
I was advised to use '93-'95 Motronic 2.9. It is simpler to install as the
later version also controls the emissions which can be tricky to work with.
Has anyone run a WBX with Motronic?
I know Motronic might sound un-interesting to you Digifant people. It is
however a refinement of Bosch fuel injection and has similarities to
Digifant.
A good source of reading is the Bosch Fuel injection book-it can give you a
good understanding of Digifant with a troubleshooting section also.
Motronic is interesting reading .
Ultimately changing to a Motronic engine such as my do-it yourself project
or the Ticco is the way to eliminate your AFM troubles forever.
Robert K
1982 Westfalia
----Original Message Follows----
My '91 exhibited "Vanagon Syndrome" only in cold weather. Typically
after about an hour at speed on a 300 mile trip during the winter
holiday season. I believe that the first record of this being a
recognized problem was by a Scandinavian tech who also encountered it in
cold weather and got VW to take note. This may be in a file on
Vanagon.com somewhere.
Everyone should do the "capacitor fix".
Larry A.
Stan Harrison wrote:
> I have a similar problem in cold weather, but mine is much colder in
>northern NH. There is a known Vanagon problem with the AFM, but I
>haven't heard anyone relate it to cold weater.
> But I believe in my case a frost film is developing on the resistance
>material, and insulating it from the wiper. (This is what I found in a
>test in my freezer.)
> When this happens parking with it idling always cures it.
>Stan
>87 Syncro
>
>K G Gilbert wrote:
>
>>Dear Volkans,
>>
>>1. My '84 Westy and I reside in the Mid-Atlantic. Once cold weather
>>starts
>>(<40 F is cold), the van experiences an occasional, intermittent
>>"miss", while
>>driving at highway speed. It usually goes away, but sometimes we lurch
>>off and
>>on for an hour. Tuneups and fuel and air filter replacements have been
>>performed. Is the Air Flow Meter a possible cause? Remember, this only
>>occurs in cold
>>weather, while the van is at warm temperature. Exactly what does the
>>AFM do?
>>If I need one, is a junkyard part ok? How much should I pay?
>>
>>2. Again, in cold weather, the AT is slow to engage until the van is
>>warm. Is
>>this indicative of another way I can part with money in the future? A
>>non-VW
>>mechanic has told me NOT to change the fluid in the transmission. Hmmm?
>>
>>3. I'll be making a NE trip in October. What spare parts/supplies do
>>you all
>>regularly carry?
>>I usually carry oil, 50/50 coolant, belts, AT fluid, brake fluid, duct
>>tape,
>>etc. I'd just like to know what essentials are inside your closets.
>>
>>4. Is there an event on Cape Cod early October?
>>
>>TIA,
>>KGG
>>
>>
>
Robert
1982 Westfalia 1987 Wolfsburg
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