VW Golf MKVI Woes

[umkay]

Hey guys,

Long time lurker here, but I see a lot of people here are quite informed about cars so I thought I'd ask for a second opinion.

I have a beautiful MKVI Golf 1.4 TSI (122PS) SE, manual, 09 plate with 77K on the clock. It has always been my trusty steed and we have owned it for almost five years now with no major problems. A few weeks ago during a road trip, the EPC light came on and the engine started running rough. I had to limp home at around 40-50mph on the M4 as accelerating or gradients induced vibrations.

I could tell from my limited knowledge that it was most likely an issue with one cylinder not firing properly. When I got my destination the engine cut itself out (it didn't like being in low revs) whilst parked. I restarted and it fired up with no issues. I restarted a few times and nothing, no EPC light. Everything seem to be running well. I thought this was a little odd, but let it be. A few days later the EPC light comes on again this time with an engine management light too whilst in stop start traffic. Again getting to my destination and restarting caused the problem to disappear. I was away from home on business and my Dad (who knows his way around cars a lot better than me) told me to see if I could get it home the end of the following week. I had no problems after that, no warning lights, no rough running for almost two weeks. Fast forward to last weekend, I managed to get it 200 miles from London to Manchester with no issues.

My Dad hooked up his VAG device to get the read outs and we got the following (can provide codes if necessary):
- Missfire detected in Cylinder 4

As well as this we hooked up the VAG to run some parameters. The idle revs were jumping between 640rpm and 680rpm. Missfires on cylinder 4 were being detected at idle, but increasing power caused the missfire to disappear as the missfire count did not go up. Returning to idle revs again the missfire count would start to increase.

We changed the spark plug and coil pack on that cylinder and didn't see any improvement. We thought it might be the fuel injector so my Dad took it into an authorised VW garage (but not VW themselves) who charged £60 to take a look. They told us that there was a low compression detected on cylinder four which was causing the missfire. They recommended the cylinder head would have to come off to see if there are damaged valves or to see what else could be broken. The price for just this investigation would be £550 and the repairs to either the head or piston rings were well into the thousands.

At this point it doesn't seem economically viable to put thousands into a nine year old car which is only worth around £5500 (according to similar spec, age and milage on Autotrader). However we paid close to £10K for this car just over four years ago, so it seems unusual to experience a mechanical issue at a relatively young age for a well cared for and maintained car with low milage. We've always had Golfs in our family and this was my first, so naturally I'm quite attached to my car (as I'm sure some of you are too!) so hoping not to have to scrap it. According to the specialist, this is not unusual for these engines, but I'm not sure how much I'm buying that.

Anyhow, apologies for any mechanical ignorance here - any input would be highly valued. Many thanks!

Kind regards,

 

[marcus_667]

Has timing chain guides been inspected or changed in any of the services while in your possession

EDIT: there is also piston ring issues with that engine

 

[Rroff]

Some quick google suggests it might simply be down to the fuel being used and that it can be fussy with fuel (EDIT: though if the result is valve damage then that is kind of moot at this point). Dunno if those engines have any of the turbo related issues that happen on some VWs which can also cause you to limp home sometimes with errors that aren't directly related to the turbo - don't really know much about the TSI engines.

 

[nas]

possibly the high pressure fuel pump

 

[Dis86]

HP fuel pump could be an option. Could be a knackered injector.

Did they actually try a compression test or just a code reader?

 

[MarkeR]

Check all your tubing. I had a similar problem turned out some of my rubber tubing was rotten and it couldn't keep the airflow or compression which caused he misfire. The symptoms were exactly as you describe.
£150 for tubing and 2 hours later all fixed.

 

[hominid]

The fuel pump would most likely give problems with more than one cylinder, plus it should throw a code if too low, so I'd take a guess at injector. You could do a leak down test to check the cylinder/rings, if you definitely have low compression with no leak down, rings/cylinder ok, then I'd check the valves for carbon build up as it's a problem with the direct injection engines.

All relatively easy/cheap things to check.

 

[Orionaut]

Do you have the actual engine code? Some of these engines have issues with the hydraulic lifters becoming "Sticky" which produces symptoms similar to that resulting from tight valve clearances on older adjustable engines. (Compression issues and High HC/O2 emissions at idle. It would be interesting to see what a 4 gas analysis looked like)

The fix is easy enough but does involve an element of striping down.

Hydraulic lifter treatment (EG Wynns) sometimes helps, but like many "Mechanic in a can" solutions. cant be guaranteed to do so.

 

[sovietspybob]

Be interesting to know if they did a proper compression test or was it just a code in the ECU?

Don't know anything about VAG stuff but are the valves clearances adjustable on these?

 

[Marv12]

I have an identical problem to what is described. What was the outcome OP ?

 

[Duke]

If you decide to let it go, speak to these guys - https://www.youtube.com/c/salvagerebuildsuk - as they're in the SE and fix up stuff like this and sell on. They won't fix customers cars though, you'd have to sell it to them. Good guys and worth watching if interested in that sort of thing

 

[Marv12]

Wanted to update on the outcome of my car (to date) as it might be useful information for someone else. I had an identical problem to the OP.

After reading a bit more about possible problems, I came to the conclusion that the low compression was likely caused by a valve sticking open due to carbon build up in the engine. I tested for an open valve using a piece of paper near the exhaust which show it was blowing and sucking.

I treated this with a couple of shots of redex to clean the fuel system and also Wynn's Hydraulic Valve Lifter Treatment which seems to have done the trick. It's been almost a month and I am still unable to reproduce the error which was easy to do before.
Fingers crossed this has done the trick.

 

[Doobedoo]

That’s why I run Millers Ecomax in every other tank.

Petrol Power ECOMAX - Multi-Shot

A Petrol fuel treatment to increases power, reduces emissions, improve fuel economy, and clean injectors. Add to your fuel tank prior to fill.

www.millersoils.co.uk

 

[red eye]

Valve, piston ring damage can be identified with a compression test, the tool is not expensive about £5 from machine mart when I got mine.

You remove all plugs and attach the tester to where the plugs go, turn the engine over and it’ll read the compression should be no lower than 90psi and should be equal on all cylinders