Date: Sat, 23 Oct 2010 19:27:50 -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: WAS: OBD Reader.... NOW: High and Low Voltage Wires. Problem
Solved??
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hi
re
IF interference from high tension leads was affecting power to/from
the idle air control valve, would this affect it's behavior?
sure ..
but ...
we naturally route plug wires by themselves..
but with your engine ..
even in stock car ..
things are close to the distributor and plug wires ...
also ..if it's just uneven for 5 seconds..
I sure would not worry about that !
those codes 'BY THEMSELEVES' do not mean a lot to me..
like 'if that' s the only, or near only symptom...
throws a code, but it works well otherwise..
starts nicely, idles well, goes good, has good fuel economy ..
I wouldn't worry about it.
it could have a sticky idle control valve perhaps ..
and it would be fun to test about proximity to plug wires ..
and perhaps it could use some cleaning or a new (expensive ) one ..
but even still...
if The Only symptom is uneven idle for 5 seconds....
as you may know, after CEL's came out ..
people were forever going to dealers to get them checked out and cleared,
and half the time there wasn't really anything wrong ( when CEL on was THE
ONLY symptom of any kind on the whole car ) ..
the dealer would just shrug, reset it, and send the car back out.
That happened a LOT when CEL's first appeared.
btw ..OBD-I is about 25 times smarter about turning on the CEL than OBD1 is.
OBD2 can even turn it back off ..
it can store pending codes..
I'm sure part of making OBD2 more right was making it so it didn't turn on
the light so needlessly and easily.
Seriously.
get that haynes book on OBD-II..
at least for me, it made me understand OBDI a lot more. ..
and how Very Limited OBD-I really is. ..
at least for subtle things.
I'd not even have the CEL on the dash .
I often put them in the engine compartment.
I don't want to be distracted from my sense of how the engine is running by
some darn light.
when there is a 'real' problem ..
and OBD will point the direction ..fine.
but otherwise ....it's more bother than aid almost, I think.
really ..do not put so much faith in it ..
unless you are working on a Real problem, and a code matches the symptom .
Countless parts have been replaced just because OBD-I flagged it.
it's not that smart really.
read how smart OBD2 is .the Hayens book I suggested ......you might
appreciate it. OBD-I was an early
somewhat attempt to have on board diagnosis. ..and I dare say, it's not
really that smart.
or put it this way ..
to see some code ....like intermittant short in the ground side of something
..
I don't actually BELIEVE that ..
I just consider it.
I don't know the threshholds for OBD-I ...like if it has to see the out of
range thing just once or whatever..
but I can pretty much assure you that they went to a lot of effort with
OBD-II to make it way smarter. ..
it has to see a few drive cycles with Non-Critical things before it will
turn on the CEL.
and will even turn it back off after enough more drive cycles if the
thing being measured looks all right again. OBD-I be very dumb in
comparison.
I have just never heard of anything like electronic interference bothering
an IAC valve ....though it's probably possible.
it's usually sticky or bum control device or whatever I believe.
I'd work 10 times as much on air leaks .
and I would not get DISTRACTED by codes
unless there is a a REAL issue.
i'm sure you saw Don's take on that too.
Scott
e-4-cylinder-gas-engines
