Date: Thu, 15 Apr 2010 14:41:59 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Now Preventative Maintenance, Was Do U carry spare ECU?
Content-Type: text/plain; format=flowed; charset="utf-8"; reply-type=original
re
would think the same logic would apply to the vanagon ECU? But instead of
replacing you would take a peek to see how far the carbon was worn? Then
repair if necessary?
I've been waiting to see if someone is going to catch this.
the poster talks like the ECU has a sweeper arm in it.
It doesn't of course ...the Air Flow Meter has a sweeper arm,
and checking that once in a while can't hurt I suppose.
probably just a slip of the word in the mind. I'm sure the difference
between ECU and AFM is well understood on this list !
< I got a gorgeous light blue Diesel Mercedes Benz that way once. Chain
got too long, guy put in a new vacuum pump, it ate that right away, cam
timing jumped on the loose chain. Still turned over too, just wouldn't run.
But ...
unlike a diesel Vanagon it didn't eat the head. Sure valves hit pistons.
The 3 cam towers ( 4 cylinder 240D) just snapped off...
a clever intentional weak link by MBZ ? .....maybe, maybe.
when I took the head ( cast iron ) to the machine ship they said 'oh, just a
valve job' and it'll be fine. ( had to get cam towers of course )
The same failure in a VW is terminal to the head at least .
re
Would you wait until your oil failed before replacing it? Or would you wait
until all of the corrosion inhibitors were used up in your coolant before
replacing it?
:"I wouldn't but this seems to be how we maintain vehicles in this country."
many people do for sure, but not anyone that follows this list I don't think
!
left over from the old days ...when you COULD tell a car needed attention
because it didn't run as nicely as usual -That's not the case anymore with
self-tuning modern cars. So thinking 'she's running as nicely as ever' means
that it's not due for anything is.............well 'not advised.'
----- Original Message -----
From: "Tom Hargrave" <thargrav@HIWAAY.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, April 15, 2010 9:48 AM
Subject: Re: Now Preventative Maintenance, Was Do U carry spare ECU?
The study is absolutely correct. But my "generic" PM list includes service
items and vehicle specific items with known failure rates. For example, the
vacuum pump on a late 80's Mercedes diesel engine is known to disintegrate
somewhere after 160,000 miles, taking the IP timer & sometimes the rest of
the engine with it. The problem is a roller bearing fails suddenly and you
know only when it's too late, sending hard metal parts into the engine. So I
replaced it at 150K miles even though the one I took off "looked fine".
I would think the same logic would apply to the vanagon ECU? But instead of
replacing you would take a peek to see how far the carbon was worn? Then
repair if necessary?
Would you wait until your oil failed before replacing it? Or would you wait
until all of the corrosion inhibitors were used up in your coolant before
replacing it?
I wouldn't but this seems to be how we maintain vehicles in this country.
Tom
www.kegkits.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Loren Busch
Sent: Thursday, April 15, 2010 10:28 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Now Preventative Maintenance, Was Do U carry spare ECU?
On Thu, Apr 15, 2010 at 7:47 AM, mark drillock <mdrillock@cox.net> wrote:
> It is a fine theory to say replace things in advance of their failure
> but experience shows that the replacement parts are often what fails
> these days. Whether that is due to declining parts quality or lack of
> workmanship in the replacing, I'd say some of both.
>
Mark has a good point here. In the 1950's the US Navy did a study on the
value of 'preventative maintenance' on electrical and electronic devices.
This was back before printed circuits and solid state electronics. Most
control and switching circuits were relays and many of the relays were open,
not encased, like in cross bar switches. And regs at the time called for
periodic cleaning of the relay contacts. They found that their down time
and failure rate dropped dramatically when they quit doing the cleaning,
only cleaned (reads 'messed with') things when there was a failure or
malfunction. The process of doing the preventive maintenance was causing
more problems than it was preventing. Later studies confirmed this for
other electrical and electronic devices. They also arrived at the
conclusion that 80% or better of failures in electronics (especially after
the introduction of solid state devices) was mechanical in nature, bad
connectors, corroded connectors, broken pins, poor contact, etc.
Now, how many times on this list have we read about problems arising right
after work has been done or parts replaced? And how often have various
problems been diagnosed as loose connections, corroded wires and plugs and
connectors, corroded gronds, etc? The mechanical part of the equation.