Running rough, Please Help

[bixler]

Hey

I'm very new to VW and by no means an expert.. But I did have very similar issues recently on my 2.0l golf. Running rich, losing power randomly when accelerating, stalling at idle, terrible fuel economy. Very unsettling and no codes being spat whatsoever.

After a bit of reading and advice here I looked to the MAF. My understanding is that if the car runs better with the MAF unplugged, then its a good indicator the MAF is cooked. In my case the stalling, rough idle, loss of power all dissappeared when i unplugged the MAF. Ended up taking a punt and forking out a bit over $200 for a new Bosch unit. Can be had cheaper online but I couldnt wait. 5 Minute changeover and straight away running perfectly. Been a few months now without drama.

That's my story anyway.. I'm no mechanic and I agree you'll neverknow for sure without proper testing. In my case I was "lucky" and guessed right first time around.

Cheers

[neilbarrett]

this is what Im thinking. replace bypass valves. try to test the maf sensor.
Do you think it could be the ICM?

[h100vw]

It would be pretty gutless if the ICM had gone. If you disconnect the coilpacks one at a time and there's no change in the running. That could indicate a problem on the cylinder. Which given the bolt down coilpacks are better than the push on ones of the same era. Would point to the ICM for me.

You could remove the coilpacks and shove the plugs in, then crank the motor over and see if they are all sparking.

The easiest way to test the MAF is by replacement or log with VCDS if you have it.

Gavin

[neilbarrett]

It runs fine and then all of a sudden loses power splutters and jerks and then eventually stalls when I stop. wouldnt that make it impossible to check the ICM that way? is there any other way to check it?

[Manaz]

ECUs keep track of historical data too if the error is bad enough. An ICM fault will likely be logged and require clearing from the ECU.

If it's the MAF, a real-time scan of the MAF readings will show that up pretty quickly.

Not sure how many times this needs to be said to you - get the car scanned with a proper tool, by someone who knows what they're doing. Seriously. Otherwise you're at best guessing (and we've seen where that's gotten you so far). Diagnosis via the Internet is hardly proven troubleshooting technique...

[h100vw]

The ME3.8 is pretty dumb so MAF faults are hard to pick.

Neil, All I wanted to hear was that you get a spark off every Plug. If not, then you want to know why. You don't need the engine running, if fact it won't run with no plugs in it. You just crank it and look for sparks.

Gavin

EDIT amplifier test

https://www.google.com.au/search?q=vw+icm+test&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[neilbarrett]

Gavin

Cheers for clearing that up bud, I will get onto it tomorrow. Sorry for the lack of knowledge.

[neilbarrett]

Manaz,

It has been scanned by Eurotune Gc who specialize in vw, apr upgrades including ecu , and have their own mk6 that they have tweaked. All they could find was a air/fuel mix problem. Im thinking of investing in VC-DS. What do you think?

[Manaz]

Manaz,

It has been scanned by Eurotune Gc who specialize in vw, apr upgrades including ecu , and have their own mk6 that they have tweaked. All they could find was a air/fuel mix problem. Im thinking of investing in VC-DS. What do you think?

The AFR is the symptom. They should have been able to extract (mostly) real-time readings from the MAF (from which the engine determines how much fuel to inject, and thus the theoretical AFR - which apparently is different to the actual). If those seem right, then the MAF probably isn't the issue.

I know you can get a (mostly) real-time reading, because I did it myself as a before & after when I upgraded the air intake on my Bora to the Mk4 DSG R32 version from overseas.

[Jmac]

The ME3.8 is pretty dumb so MAF faults are hard to pick.

Neil, All I wanted to hear was that you get a spark off every Plug. If not, then you want to know why. You don't need the engine running, if fact it won't run with no plugs in it. You just crank it and look for sparks.

Gavin

EDIT amplifier test

https://www.google.com.au/search?q=v...ient=firefox-a

Its only dumb if you are only using a scanner, hardly needed to say that but the scanner isnt the be all and end all. Good baseline though, but i know and have seen guys scratch there heads with misfires and the scanner says nothing, remove all the intelligent stuff and there is an otto cycle going oin in there same as it did on a Model T. The basics need to be understood, serious dramas are going to happen on the new stuff and thats for sure, they dont tolerate just pulling off this and that to see it there is a spark or misfires etc, try it on a piezo injector and you will have a conrod firing out the side of the block. Just had to mention, i know we are talking about a basic engine here but really only trying to help, as ive seen it
Hope you have had luck with your problem
Cheers
Jmac

[neilbarrett]

changed the little bypass valve and pipe work on the evap system. Seems to be running a lot better, no sputtering, no stalling etc. hopefully this little valve was the culprit.

[neilbarrett]

BACK AGAIN!!!

She was running sweet again for a couple of days and then all of a sudden back again. splutter shuder run rough then stall on stoping. leave her over night next day running fine. WTF!!! back to the drawing board I guess. Any sugestions??? ($520 and counting)

[neilbarrett]

guess its back to the mechanics ??

[neilbarrett]

Back again,
took it in to the mechanics they had it for three days saying they need it for that long to do a proper diagnosis. They came back saying it was a faulty purge valve in the evap system.($340) Drove away problem still there!!! took it straight back. They couldn't find anything wrong. took it for a drive car was running fine (typical) they then told me it could be a faulty fuel cap WTF. Drove home with the car still running fine. Next day problem is back again (starts spluttering violently, nothing when I put my foot down on the accelerator then eventually stalls). This time I pulled over car still running (Just) and noticed alot of black smoke coming from the exhaust. Called the mechanic back and they said I can take it back next monday. Can someone please help me Ive had this problem for around 2 months now and its driving me crazy!!!

note, the mechanics are euro mechanics all bosch qualified and the claim their diag software is better than vag com and they cant find any thing wrong.

[jamesdavid]

Neil, when it happens, you put your foot down to the floor, do the revs continue to rise but the cars exhibits no acceleration whatsoever? Is there a point in the rev range where the car will drive normally but as soon as it hits say 2500rpm - 3000rpm the acceleration just dies?

Cheers,

James