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/foru...elp-27504.html

Rip through here and PM someone.

[jarredking]

thanks

[jarredking]

anyone?