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Failed 3 E-Tests Volkswagen MK 2 Eratic Idling



 
 
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  #1  
Old May 7th 05, 03:22 AM
Spar
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Default Failed 3 E-Tests Volkswagen MK 2 Eratic Idling

I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
the third 3rd time it failed.
Have installed new oxygen sensor, new catalytic convertor, new plugs and
changed the oil. The vehicle does have eratic idling at certain times and
not all the time.
One mechanic today suggested I change the Idle Stabilizer Valve.
Would appreciate hearing from anyone who has experienced eratic idling and
have them advise me
what repair was necessary to fix it.
Thanks
Spar


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  #2  
Old May 7th 05, 04:27 AM
Randolph
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Spar wrote:
>
> I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
> the third 3rd time it failed.
> Have installed new oxygen sensor, new catalytic convertor, new plugs and
> changed the oil. The vehicle does have eratic idling at certain times and
> not all the time.
> One mechanic today suggested I change the Idle Stabilizer Valve.
> Would appreciate hearing from anyone who has experienced eratic idling and
> have them advise me
> what repair was necessary to fix it.
> Thanks
> Spar


Please post the results of the E-test (CO, HC, NOx, O2 etc.) as it is
immensely useful in diagnosing an emissions problem. What type of fuel
injection do you have? Digifant I, Digifant II? something else entirely?

A new ISV is expensive, don't change it unless you /know/ it is the
problem. One common problem on A2 cars is that the idle switch on the
throttle body fails (the one at the bottom that you can barely see, the
one in plain view on top is the wide open throttle switch). This will
cause erratic idle. Depending on what type of FI you have, you may or
may not have an idle switch.
  #3  
Old May 7th 05, 10:54 AM
Woodchuck
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Why did it fail? Let's see the test results!

"Spar" > wrote in message
...
>I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
> the third 3rd time it failed.
> Have installed new oxygen sensor, new catalytic convertor, new plugs and
> changed the oil. The vehicle does have eratic idling at certain times and
> not all the time.
> One mechanic today suggested I change the Idle Stabilizer Valve.
> Would appreciate hearing from anyone who has experienced eratic idling and
> have them advise me
> what repair was necessary to fix it.
> Thanks
> Spar
>
>



  #4  
Old May 7th 05, 03:07 PM
Bernd Felsche
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"Spar" > writes:

>I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and
>this is the third 3rd time it failed.


How? What doesn't measure up?

>Have installed new oxygen sensor, new catalytic convertor, new
>plugs and changed the oil. The vehicle does have eratic idling at
>certain times and not all the time.


>One mechanic today suggested I change the Idle Stabilizer Valve.


Oh yeah... there are lots of cheaper things to fix like the grommet
between the head and the PCV valve; the probably-perished rubber
vacuum tube joiners and lines around the throttle body.

Also check the dipstick tube; especially the plastic end where the
dipstick is supposed to seat "air-tight".

And then making sure that the electrical connections to the cylinder
head are good; both at the corner of the cam cover and at the side
coolant flange.

Then there are other bits to check; like the coolant temperature
sensor.

>Would appreciate hearing from anyone who has experienced eratic
>idling and have them advise me what repair was necessary to fix it.


Mostly; a few drops of Stabilant 22A inside the air-flow meter; at
the connector and on the carbon track.

You can also clean the ISV.
--
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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/ \ and postings | to help me spread!
  #5  
Old May 7th 05, 04:16 PM
Matt B.
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"Spar" > wrote in message
...
>I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
> the third 3rd time it failed.
> Have installed new oxygen sensor, new catalytic convertor, new plugs and
> changed the oil. The vehicle does have eratic idling at certain times and
> not all the time.
> One mechanic today suggested I change the Idle Stabilizer Valve.
> Would appreciate hearing from anyone who has experienced eratic idling and
> have them advise me
> what repair was necessary to fix it.


Judging from your email you're in Canada and probably have a Digifant II
system.

The ISV can be cleaned out with carburetor cleaning solvent. Remove it from
the car and spray the solvent into ever hole really good. This sometimes
helps.

Also make sure that any and all vacuum lines are good and no leaks. Also
check the PCV valve grommet on top of the valve cover and that the oil
dipstick is seated properly. Any of those things, if leaking, will cause a
vacuum leak and possible erratic idling. The coolant temperature sensor for
the ECU also often goes bad (although usually the symptom of that is a rich
high idle and not an erratic one) but it's a cheap thing to replace. As
others have noted, the ISV is expensive and I've never heard of them going
bad very often. There are other cheaper things to check first.


  #6  
Old May 9th 05, 06:31 PM
dan
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Spar > wrote:
> I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
> the third 3rd time it failed.
> Have installed new oxygen sensor, new catalytic convertor, new plugs and
> changed the oil. The vehicle does have eratic idling at certain times and
> not all the time.
> One mechanic today suggested I change the Idle Stabilizer Valve.
> Would appreciate hearing from anyone who has experienced eratic idling and
> have them advise me
> what repair was necessary to fix it.


As others have noted, it would help a lot if you posted what fuel injection
your car is equipped with and what your emissions numbers are. They tell
you all that stuff for a reason.

High NOx is usually an indication that the engine is running hot. This
can be caused by a variety of things, including incorrect ignition timing,
low octane fuel (lower than you need), faulty EGR valve (if equipped), or
bad cat.

High CO is virtually always an indicator you are running rich.

High HC is an indicator you are burning something, either fuel or oil. If
your CO levels are low, it probably means you are burning oil, if your CO
levels are high its probably running rich.

A faulty catalytic converter can affect all three readings, however
catalytic converters generally speaking are only effective if the car is
running relatively cleanly to begin with, so if you have a high CO
reading, the cat would be the last thing I'd check and the O2 sensor and
the coolant temperature sensors would be the first. The coolant
temperature sensor is just a thermistor and can be checked easily with a
multimeter.

I hear a lot of people complaining of erratic idle and the first thing
they want to do is replace the idle stabalizer valve. I personally have
rarely seen one fail. They can be cleaned with carburetor or fuel
injection cleaner as others have mentioned, but I'm not even convinced
thats that much help. The first thing to do is to simply unplug the
idle stabalizer valve and see what happens. One thing that most people
don't realize is that a PROPERLY functioning idle stabalizer valve can
turn what seems like a minor idle problem into a major one because of its
nature as an active feedback system.

An erratic idle (and nothing else) is usually caused by an air leak.
Common places are in anything rubber, around hose clamps (make sure they
are tight), vacuum lines, particularly rubber ones or the rubber joints,
and around the fuel injectors. If you have CIS based injection it might
behoove you to pull out the injectors and injector inserts and replace the
lower insert and all the seals (2 on the injector one on the lower
insert). As someone else suggested, it's probably a good idea to check
the WOT and idle switches. One generally good thing to try is to start
the car, and then push/squeeze/twist/pump anything that is flexible. This
should have virtually no impact on the idle quality. If it does you found
a problem, look for rips, tears, or loose connections.

dan
  #7  
Old May 11th 05, 03:14 AM
dave AKA vwdoc1
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Default

Like others have said..............check the idle and WOT switches.
I will assume that you have the Digifant II system, but I am not sure on
this.
If you do you might find a wiring problem at the intake manifold or cylinder
head (ground wire breaks)
Or maybe a defective Fuel Pressure Regulator.

IF CIS-x, it might be a wiring issue (again ground) at the cold start valve.

Just to give you more things to check.
DON'T JUST THROW PARTS AT IT!!! Check it out with a digital Volt Ohm Meter
and a good book (Bentley). ;-)

--

later,
dave
(One out of many daves)


"dan" > wrote in message
...
> Spar > wrote:
>> I took my 1990 Volkswagen Golf Mk2 into get it E-tested today and this is
>> the third 3rd time it failed.
>> Have installed new oxygen sensor, new catalytic convertor, new plugs and
>> changed the oil. The vehicle does have eratic idling at certain times
>> and
>> not all the time.
>> One mechanic today suggested I change the Idle Stabilizer Valve.
>> Would appreciate hearing from anyone who has experienced eratic idling
>> and
>> have them advise me
>> what repair was necessary to fix it.



 




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