Re: O/T slightly VW Maintenance Reality Check


halatos@xxxxxxxxx wrote:
By periodically interrogating the OBD system and creating an archive of
the results you can see various components slowly degrade over time,
allowing you to schedule their replacement well before any failure can
occur. Of course, to do that you need to be able to connect to the
on-board computer with a PC or lap-top running suitable software, which
is commonly available. Some software facilitates this by linking parts
procurement to the diagnostics, allowing you to place an order by
simply right-clicking the mouse.


Bob,

This is a project I have been dabbling in for some time with my 1997
Kia. The Davis Instrument "Car Chip E/X" can retreive all four types of
OBD-II diagnostic codes and monitor up to 4 sensors at a time. The nice
part is that the car chip is about the size of a box of matches and can
remain attached to the OBD-II connector, logging data in 5 second
intervals that can be pulled out into a desktop or laptop when it is
convenient, rather than lugging around a laptop for constant
monitoring.

Ideally to get the best results one would start with a new car, take
readings from day one of all the sensors, and repeat as necessary to
see over time what sensors are drifting out of tolerance. The other
thing to consider is the replacement interval that is specified for
things like O2 sensors and MAF sensors, which from what I've researched
are usually spec'd out at 100,000 miles MTBF.

Getting back on topic, I still like driving my VW because of simplicity
and the number of "Point and stare" people you see now that the
aircooled VW is an antique. However, fuel injection, air conditioning,
heat, cruise control and all those other features of 'modern cars' do
make life a hell of a lot more comfortable on a long trip or the daily
commute ;-)

Regards,

Chris

Yup, that CarChip is a nice tool -- I maintain all my own cars so have
one out of necessity.
It is presently in my in-laws Altima.

Their Altima had been stalling for some reason at random. It would
become hard to start and then drive fine again -- all without rhyme or
reason. It would turn the light on the dash on from time to time.

The Nissan tool (both the actual scan tool and the guy working on that
car - I use the word interchangeable in this discussion) diagnosed the
problem and felt it was necessary to replace the crank sensor, some
secondary o2 sensor and some other sensor. This was in two dealer
visits, neither fixing the intermittent problem -- all because a
particular random code was thrown.

After the third time of visiting the dealership, the manager mentioned
that they'll need a new computer ($1100 + installation). He mentioned
that the ECM must be the cause of all the problems because none of the
stuff they've been replacing makes any sense. He suggested it might be
related to a stopped up AC drain hose. Mind you, he did not suggest
giving them their money back ($900) for the other randomly performed
service.

$1100 is a lot for retirees so they drove it back home, not getting it
serviced.
I just found it hard to believe it was the ECM. After some probing
around with a DVM, found a bad ground connection to the battery and one
to the ECM. Fixed the connections and the car has been running fine
since (but still have the carchip recording stuff, just in case).

So Bob's absolutely right. I like technology, but learned to never
trust it implicitly. There's no better computer than the one between
your ears. Too bad the Nissan tools don't know that..

Remco

.

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