Date: Sat, 17 May 2008 01:47:55 -0400
Reply-To: pickle vanagon <greenvanagon@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: pickle vanagon <greenvanagon@GMAIL.COM>
Subject: hesitation/bucking (was: Re: tested Oxygen Sensor, and...)
Content-Type: text/plain; charset=ISO-8859-1
Thanks for all of the responses, guys.
I think maybe the first time I hadn't let the van heat up enough. (The
engine was already warm, but maybe I didn't actually let the sensor heat up
enough?)
When I measured again, I did get fluctuation, but the swing wasn't as large
as .5volts. I'd say ut swung between around .4 and .7. I guess its
possible that there was actually a greater swing than was showing up on my
digital voltmeter. I should mention: the oxygen sensor is only about 4000
miles old.
Anyways, the reason I was checking the oxygen sensor voltage in the first
place, is that I've noticed recently (since my head job...) that the van
occasionally exhibits some slight hesitation symptoms when driving at a
constant speed (usually low speed, so low load). The van surges slightly
forward and back, maybe at a rate of once per second or so, kind of like
very minor bucking. It only has happened occasionally, so I can't say for
sure when it seems to happen the most. But it has never happened when
accelerating or otherwise when under load, and it has never caused any
problems idling. It idles very smoothly, although it seems to me that it's
idling at lower rpms than before. Of course I don't have a tach so I can't
say for sure.
What should I look for with these symptoms? The only things I've done are:
looked around for any obvious vacuum leaks, checked the oxygen sensor as
above, rechecked my valve adjustment, checked my Temp 2 sensor, and replaced
the engine compartment ground strap (the one that goes to the head). I'm
guessing that with a problem like this, there's a list of 50 things to
check.
I guess I should really be checking the mixture properly in a situation like
this, but I don't have an co meter or anything for the exhaust.
Thanks for any pointers,
Wes
1.9l westy
On Fri, May 16, 2008 at 11:25 PM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:
> A steady reading of .5 to .6 volt is a sign of an open sensor or one that
> has not heated up enough to function. The voltage is due to the leakage at
> the ECU input. Measure the voltage at the sensor lead with it disconnected
> to see if you are really getting a signal.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> pickle vanagon
> Sent: Friday, May 16, 2008 5:53 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: tested Oxygen Sensor, and...
>
> Just for fun, I decided to go out and "test" my oxygen sensor today, by
> which I mean I warmed up the car, and then checked the voltage coming off
> the sensor wire with the van at idle. I got readings of around .52 volts,
> which maybe seems okay (?), but the voltage was steady, not oscillating
> (it
> stayed between .51 and .53 volts always). Does this mean my engine is
> never
> entering closed loop operation? If so, what are the standard things to
> check, since the O2 sensor seems okay?
>
> Thanks,
> Wes
>
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