2003 New Beetle 1.6L running rough

[jarredking]

Hi Guys,

First timer on here. Partner has a 1.6L 2003 Icon Beetle.

Lately on first start up its running rough, idle going up and down aggressively almost like it has a lumpy cam. After a quick rev it goes away.

Its had plugs just done, service, fuel injector cleaner, airfilter is ok. O2 sensor was replaced a month ago as it had a fault code for that.

No engine lights coming up for this issue. im thinking maybe MAF sensor? Ive checked the engine breather hose as i was told they crack or break and its fine.

Symptoms:
Rough idle
Smells really fuelly
Idle can run on with a small amount of throttle applied, doesnt return back to idle straight away.
Fuel milage is worse than when first bought.

any help?

[h100vw]

Hi Guys,

First timer on here. Partner has a 1.6L 2003 Icon Beetle.

Lately on first start up its running rough, idle going up and down aggressively almost like it has a lumpy cam. After a quick rev it goes away.

Its had plugs just done, service, fuel injector cleaner, airfilter is ok. O2 sensor was replaced a month ago as it had a fault code for that.

No engine lights coming up for this issue. im thinking maybe MAF sensor? Ive checked the engine breather hose as i was told they crack or break and its fine.

Symptoms:
Rough idle
Smells really fuelly
Idle can run on with a small amount of throttle applied, doesnt return back to idle straight away.
Fuel milage is worse than when first bought.

any help?

Welcome to the forum.

I'd try a water temp sensor, just a speculative change though to be fair. The best and only correct approach with any defect like this is to scan it with a real scanner, that can see live data.

VCDS being my scanner of choice.

Then you can see if there's an output from all the sensors and what it is telling the ECU. You could see the MAF g/s and determine if it's a credible value, before throwing money into a new one.

Likewise, you could see if the ECU is being told about the engine temp.

Gavin

[jarredking]

Hi Guys,

First timer on here. Partner has a 1.6L 2003 Icon Beetle.

Lately on first start up its running rough, idle going up and down aggressively almost like it has a lumpy cam. After a quick rev it goes away.

Its had plugs just done, service, fuel injector cleaner, airfilter is ok. O2 sensor was replaced a month ago as it had a fault code for that.

No engine lights coming up for this issue. im thinking maybe MAF sensor? Ive checked the engine breather hose as i was told they crack or break and its fine.

Symptoms:
Rough idle
Smells really fuelly
Idle can run on with a small amount of throttle applied, doesnt return back to idle straight away.
Fuel milage is worse than when first bought.

any help?

Welcome to the forum.

I'd try a water temp sensor, just a speculative change though to be fair. The best and only correct approach with any defect like this is to scan it with a real scanner, that can see live data.

VCDS being my scanner of choice.

Then you can see if there's an output from all the sensors and what it is telling the ECU. You could see the MAF g/s and determine if it's a credible value, before throwing money into a new one.

Likewise, you could see if the ECU is being told about the engine temp.

Gavin

UPDATE:

Just went to the garage to run the car, started it and unplugged MAF sensor while running and no change in engine RPM or sound, i assume MAF is dead?

If a working MAF is unplugged car should run very rough right?

How much is one of those scanners and where from

[tigger73]

Car will just revert to "default" values when the MAF sensor is disconnected.

Have a look over here for VCDS info: VCDS Technical Resources

[h100vw]

Putting your location will help. Australia is pretty big and there's plenty of people on the forum like myself that would do a scan for beer money.

VCDS is about $400, there's others but you'll have to google that, I have VCDS and don't know about any of the others.

It's good indication but you be pretty upset if you blow a couple of hundred on a MAF and that's not it. Do the diagnosis properly and save money in the long run

Gavin

[jarredking]

darn, so i was onto nothing there. Are these vag-coms worth it? there only $50 on ebay

[jarredking]

Thanks Gavin, didnt realise they actually diagnosed, just thought they were only a rough guide. Im in newcastle NSW

[h100vw]

darn, so i was onto nothing there. Are these vag-coms worth it? there only $50 on ebay

The ebay cables are not VCDS. I have a real one and can't say whether the ebay ones work like, even if you use VCDS lite and pay for it?

There would have to be someone in Newcastle that can help you.

I did create a thread with names and locations. Let me find it for you.

http://www.vwwatercooled.org.au/forums/f20/vag-com-scanning-who-can-help-27504.html

Rip through here and PM someone.

[jarredking]

thanks

[jarredking]

anyone?

[Lucas_R]

anyone?

I have VCDS and am in Newcastle but not sure if my version of VCDS (as their are several types) will work on a 2003 Beetle. The oldest VW ive used it on is my friends 2007/08 Golf GTI.

Its worth a try though if you want. Providing it communicates with your car, i will be able to run a scan of the ECU to read the error codes its stored which will give you a pretty clear indication of what the issue could be.

[tigger73]

You'll need a Hex-can not a micro-can cable to talk to the new beetle.


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[Lucas_R]

You'll need a Hex-can not a micro-can cable to talk to the new beetle.

^ yeh that's what i thought. I cant remember which version i have - will have to check tonight.

[jarredking]

thanks let me know because i am booking in tomorrow with VW and they are charging me $80 just to plug scanner in!

[Lucas_R]

thanks let me know because i am booking in tomorrow with VW and they are charging me $80 just to plug scanner in!

And to think i was only going to charge you $75......i need to put my prices up

$80 for a diagnosis isnt bad, at least they will have the right tool for the job, im not sure if the one i have will work on cars older than the Mk5 era which was 2005 or so. Anyway, ill have a look tonight at which version i have and ill let you know.