Quick question about VW Golf

[DirtyHarry]

hey guys, my brother bought a vw golf mk4 2004 2.0l -104,000km
anyway it was fine for couple of days, however now, after its warmed up, when you rev the tits out of it, it spills alot of black smoke/dust particles. (not blue...black, oil and coolant looks fine)
And the exhaust fumes smell really puttrid. Now it doesnt smell like its running rich, it just smells like rotten egg.

There is no error codes in the ecu, no dash lights either.
Everything seems to be running ok, however im stumped to figure out what it is.
COuld it be the petrol? Or could it be the charcoal canister stuffing up or could it be the Catalytic converter.

Your thoughts would be greatly appreciated. And do any of you know of any australia VW/Golf Forums?

[bornwild]

Rotten egg usually indicates a problem with the clutch/gearbox assembly.

As for the smoke, what fuel are you on? You realise that the Golf should be run on 98RON and only if you have to on 95RON? Try some injector head cleaners or something.

[DirtyHarry]

yeah, its definetly not the clutch, because it comes out of the exhaust and you can smell it, plus the black smoke.

Im not sure what petrol is in there now, as we picked it up 3 days ago and the ower filled it up with petrol before we picked it up. however even if he put say 91RON petrol, it still shouldnt be blowing heaps of black smoke.

[bornwild]

Well, I think that legally you have something like 7 days to return the vehicle to it's previous owner in case of dishonesty. Go to a mechanic you trust and tell them to check it out. It's probably worth paying for to have the piece of mind.

[DirtyHarry]

where did you hear that born?

[bornwild]

where did you hear that born?

A mate of mine had returned his car but his was involved in an accident where the complete front end was destroyed and rebuilt.

I don't know if the same law applies for NSW though....:confused:

[bornwild]

http://www.fairtrading.nsw.gov.au/corporate/publications/ftc07buyingausedcar.html

I just googled it....seems like there is no such law for neither VIC nor NSW nor any other state......Ok, don't take my word for it.

But yeah, that sounds like either there is knocking occuring or somethings wrong perhaps with the timing of the ECU...wait for some of the more experienced veterans here. :)

[blueraven]

the catalytic converter is screwed. i put money on it.

the rotten egg smell is almost always from the cat, and if its spitting crap out th eback its probably really ****ed.

[DirtyHarry]

thats what im thinking too....that its the cat. however if thats the case, shouldnt the engine emissions light show up? since the car has two oxygen sensors 1 before the cat and 1 after.

[bornwild]

thats what im thinking too....that its the cat. however if thats the case, shouldnt the engine emissions light show up? since the car has two oxygen sensors 1 before the cat and 1 after.

Exactly why I didn't even mention the cat...maybe the sensors are screwed too?

[digifish]

Rotten egg usually indicates a problem with the clutch/gearbox assembly.

That's a joke right? :confused:

Black smoke indicates running rich. A busted cat CANT cause black smoke...only bad smells...well it might if it was blocked/clogged I suppose.

I'd suggest

1. Sticky injector.
2. Sticky cold-start injector
3. ECU input sensor bung (oxygen, temp, air-flow)

digifish

[JohnBu]

Well, I think that legally you have something like 7 days to return the vehicle to it's previous owner in case of dishonesty.

A mate of mine had returned his car but his was involved in an accident where the complete front end was destroyed and rebuilt.

no such thing- its a case of caveat emptor

thats what pre-purchase inspections are for.

[rjastra]

The old MK4 2L will happily run on 95RON. It may even potter along ok on 91RON.

Get him to run the tank down then go fill it up with some nice fresh PULP. Then take it for a bit of a thrash somewhere.

[DirtyHarry]

yeah im planning to do that. run the petrol down. fill up with 98RON and put some fuel cleaner into the car while im at it.
and see what happens

[USC]

yeah im planning to do that. run the petrol down. fill up with 98RON and put some fuel cleaner into the car while im at it.
and see what happens


I have noticed the exhaust of my sri also smells slightly like rotten egg when I havent driven it for a while! my previous car--a nissan (which was also bought brand new) did the same thing. i think it must have something to do with the crap petrol we get over here. did ECU check, went to dealer for service, etc...everything was ok!

[1OPL2C]

www.vwwatercooled.org.au

all the info you need inside or you can ask another duber

[Calibrated]

dare i state the obvious?

Golf = Flog

[bornwild]

That's a joke right? :confused:


Rev n dump and see what the smell coming from the clutch is. No joke.

[USC]

Rev n dump and see what the smell coming from the clutch is. No joke.

yep...done it b4..smells like rotten egg poo...haha

use shell v power only...makes a huge difference!!

[DirtyHarry]

well so far i think it might be the pre cat oxygen sensor.
upon closer examination with the laptop i managed to observer that the sensor voltage value most of the time sits around 0.040v to 0.100v. which going by from what i understand and comparing to my astra the value should be fluctuation around 0.600-0.800v
so ill have to try and get my hands on a 2nd hand oxy sensor as VW wants $436+gst for a new one.

[USC]

well so far i think it might be the pre cat oxygen sensor.
upon closer examination with the laptop i managed to observer that the sensor voltage value most of the time sits around 0.040v to 0.100v. which going by from what i understand and comparing to my astra the value should be fluctuation around 0.600-0.800v
so ill have to try and get my hands on a 2nd hand oxy sensor as VW wants $436+gst for a new one.

OMG! that much for an O2 sensor!! try source it from europe....it will be a lot cheaper! 2nd hand one might be as bad...

[DirtyHarry]

2nd hand i got quoted around $100.
which isnt too bad i guess

[RudeOne]

you can get generic - goto repco or autobarn

[USC]

you can get generic - goto repco or autobarn

I would rather get low km second than generic....
things like sensors etc have to be genuine for best performance! oil filter etc can be generic...

[DirtyHarry]

well the generic one i can buy cheaper would be bosch. which i suppose is what the oem one would be anyway.
but anyhow, taking the car to the mechanic tomorrow have it checked out.

im just bit confused, cause if the sensor is contantly reading rich mixture then why doesnt it light up the emissions light on the dash. and the other thing is, ive been trying to find where the 2nd sensor is and i cant locate it anywhere.

[digifish]

im just bit confused, cause if the sensor is contantly reading rich mixture then why doesnt it light up the emissions light on the dash. and the other thing is, ive been trying to find where the 2nd sensor is and i cant locate it anywhere.

If it's over-fueling then it's constantly reading a lean mixture. The Bosch would be identical to the OEM BTW, VW use Bosch electrics.

There is probably only 1 sensor.

digifish

[rjastra]

Why would it be a faulty O2 sensor at WOT? Usually they are only used at partial load.

A faulty O2 sensor would throw a code and you'd get the engine check light illuminated on the dash.

[DirtyHarry]

yeah thats what im thinking aswell rjastra. and if its constantly reading a lean mixture then wouldnt that throw a code as well.

from what i could tell, the MAF sensor is working ok (i get correct temperature and air flow read outs) i cant seem to notice any air leaks.

Can VW service actually recalibrate the o2 sensor?

[USC]

yeah thats what im thinking aswell rjastra. and if its constantly reading a lean mixture then wouldnt that throw a code as well.

from what i could tell, the MAF sensor is working ok (i get correct temperature and air flow read outs) i cant seem to notice any air leaks.

Can VW service actually recalibrate the o2 sensor?


when sensors start playing up, I found that it s very hard to know which one is bad until it finally dies...

[DirtyHarry]

i managed to do some more reading and there iis a good way of diagnosing if the o2 sensor is stuffing up.

basically you need a pc with the software connected to the car and follow this. taken from the web site http://www.picotech.com/auto/lambda_sensor.html

"To check the sensor's response to changing oxygen levels in the exhaust, first create an artificially lean condition by pulling a large vacuum line. When extra air is introduced into the engine, the sensor's voltage output should drop to 0.2 V.

To check the sensor's rich response artificially richen the mixture by, if possible, clamping the return fuel line momentarily. This will force more fuel through the injectors and should cause the O2 sensor's voltage to increase to 0.8 V.

If the sensor's output fails to respond to the changes you've created in the oxygen level in the exhaust, it's time for a new sensor."

[digifish]

when sensors start playing up, I found that it s very hard to know which one is bad until it finally dies...

That's been my experience too. I once had a air-temp sensor go south on me, it wasn't until I replaced it I proved it was the problem. Careful logging of values didn't discover a fault for me.

If a sensor is open circuit or something then you can tell, but before that it can be tricky. I am sure a dealer with the appropriate ECU analysis SW and system would be able to hook it all up and see in a moment what is wrong. You can go in and ask for an analysis only, they will probably charge you for 1 hour.

digifish

[DirtyHarry]

yes they charge for 1 hour at about $130 p/h

seems like a very expensive diagnosis to me especially if it only takes them 5 minutes to diagnose it.

[digifish]

yes they charge for 1 hour at about $130 p/h

seems like a very expensive diagnosis to me especially if it only takes them 5 minutes to diagnose it.

Fair enough.

In my experience, it can save a lot of time...and is almost always worth the $$$. The fault will probably turn out to be something else...that 5 minutes will turn into 5 hours...or 5 days...it always does :)

digifish

[DirtyHarry]

haha yeah true. im still taking to the dealer on thursday, however in the mean time i would like to diagnose it my self and see what happens.
you know, its more of a hobby

[1OPL2C]

buy yourself a vag-com cable.. and the software is free from ross-tech website

[DirtyHarry]

well got word from my local mechanic, that the problem is the Throttle position sensor. His going to price it tomorrow, but going by what they sell from genuine VW (integrated with the throttle body) turns out to be about $1100. haha what a joke, i tell you, if you wanted to build a car from spare parts it would cost you a million bucks.

Apparently 2nd hand ones cost abotu $400 with 2 year warranty