Date: Wed, 12 Jul 2017 12:40:44 -0700
Reply-To: Neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Neil N <musomuso@GMAIL.COM>
Subject: Re: Anyone Tested a 2.1 AFM on 1.9 Digijet?
In-Reply-To: <CAB2Rwfgd_M8tK_TierTwbhPqFmyin5MDzSmgH1-nTGiWJqahuA@mail.gmail.com>
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So foolish and overly confident me, I chose to attempt a circuit board
"shift" on this persons' AFM while at a VW campout. Of course in the
process, one screw on the board snapped off. This was after I ***
barely *** turned the other 2 screws. (I carry a cordless drill etc.)
After breaking that one screw I stopped of course and added a little
Goop to the corner of board now missing the screw head and at the
remaining screw heads to board. On a spare 2.1 AFM (Jetta RV code
engine) those screws came out without issue.
FWIW, I measured for voltage drop out using a "just above super cheap"
Radio Shack volt meter. There wasn't a suitable voltage scale on that
meter (10 VDC, 1.5 and 9 VDC "batteries") so I couldn't really check
for voltage drop out. I did, however, set meter to 1K Ohm scale and
could see an obvious non linear change (meter dip) in resistance which
directly coincided with a small area on the resistive strip that
showed more wear than the rest of the strip. In hindsight, I should've
watched the AFM wiper while the engine was running to see if that wear
was at "cruising" RPM's or for sure not at idle. Interestingly, the
AFM looked like it had been opened up before; there was excess sealant
at edge of the plastic cover. Owner said a mechanic had adjusted the
AFM to help his bus pass emissions testing. Maybe the AFM spring was
adjusted to do so?
The bucking and engine cut out issue that has been happening to this
van (after being driven for several to many hours), happened to this
van even when it had much much lower miles on it. More and more it
seems to me that the issue really isn't wear at the resistive strip
but has to do more with the wiper not remaining dead steady causing
slightly varied voltage values inputted to the ECU. But this has been
written about before by far more educated folks than I.
Neil.
On 6/21/17, Neil N <musomuso@gmail.com> wrote:
> Thanks Ken and David. Very helpful. Will be helping a friend with a
> (or two) long time running issue on his '85. Since I'd be carrying
> parts and tools from home to this Vanagon, adapting my spare 2.1 AFM
> to his Digijet engine may be more trouble than its worth. First I'll
> measure for voltage drop out then if need be, clean the resistive
> strip on the existing AFM or move the AFM PCB forward or rearward a
> little. I know the screws holding that PCB in place can be hard to
> break loose.
--
Neil n
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