Hesitant acceleration on 1.2 6-valve

[hafsol]

Hello everyone,

 

My Fabia is at it again, this time with really annoying power losses.

Today I did 200 miles with two or so 1 hour stops on motorways at around 75mph.

While on the road, I noticed that on an incline it couldn't get past 35mph in 3rd even with my foot glued. This is all very strange to me as I've driven there before and managed 45mph with moderate effort.

Like 20 miles before getting home, I noticed that on heavy acceleration or when under 2000RPM on high gears, the car would lose power, shake violently (like a misfire) and the exhaust would also pop. This did not happen if I gave it only a dab of throttle. Turning on the AC obviously made this worse.

No lights came on before, after or during the trip and the temperature gauge was always on the middle.

However, when I got home, I looked at the engine and noticed a faint light purple/red hue by the left of the block, where the alternator is.

 

Any AWY/AZQ wizard had a similar experience? Is this just the Furby not being able to cope with long motorway journeys?

If not what do you guys think it is?

 

Thanks in advance!

 

[TMB]

 Is this just the Furby not being able to cope with long motorway journeys?

 

 

 

 

Not at all.

 

You need to get it scanned for fault codes.

[Dave89]

I've come across this before.

 

Verdict seems to be the way the valves are seated (i'm not technical) and is a problem with the AWY/AZQ across the VAG range that use it (polo etc...)

 

Undoubtedly they'll be a fault code but usually an opened ended one "fuel system too rich".  

 

Hopefully that isn't the case for you but as the above poster says, buy a cheap fault code reader or OBD cable and the free lite version of VCDS to check the codes first.

[hafsol]

Thanks for the feedback! Got the codes checked and only one showed up:

 - Catalyst System Efficiency Below Threshold Bank 1

 

I'm not sure, but this could be unburnt fuel in the cat from yesterday. It also picked up as an intermittent fault. The CEL still didn't light up. Mechanic suggests replacing all spark plugs first to see if the problem goes away.

Having cooled from yesterday, I took it for a little drive and gave it a few pushes to 4500 once it was warm. There was some hesitation but far less noticeable than yesterday.

One thing I noticed was the cooling fan being triggered every 3 or so minutes when driving slowly. Might be the summer but triggering it used to be quite hard last year.

 

Really hope it's not the dreaded exhaust valve problem...

[Breezy_Pete]

It wouldn't take your mechanic much longer at all to do a compression test while he's changing the spark-plugs. 

[hafsol]

Thanks Wino, I'll be sure to ask him that!

 

A bit of an update on this: another 200mi journey.

The slight misfiring continues, although not as harsh.

The cooling fan still triggers at low speeds and I've noticed there's an odd burning smell coming from the engine bay. I can't really describe this smell except it's a bit nauseating like burnt rubber or plastic. Burnt clutch maybe? It seems like it's coming from the radiator (or close) and with the cooling fan on I can smell it on the driver's side.

[hafsol]

Another update on this if anyone is curious:

 

Compression is fine (don't know the actual values), I was told.

It began acting up really bad and a fault code came up: Cylinder 1 misfire.

Coil #1 was replaced with #3 and the problem suddenly went away. Bad contacts maybe?

Going to have a few more miles with it and see if the codes come up again (hopefully on #3 this time...).

[hafsol]

Final update on this if anyone is interested in the outcome:

 

The car started running really rough up to a point where every hill would mean coping with a misfiring cylinder.

Engine light would pop up when misfiring but didn't stay on.

 

The codes were checked and revealed a misfire on cylinder 3, pointing at coil failure.

#3 coil was replaced with a new one and no codes appeared but the engine kept going a bit rough. 3 new spark plugs did the job!

Total cost was 100€ (60€ for 1 coil, 10€ per spark plug + service).

I managed to avoid the dreaded burnt valve problem for now I guess.

 

TL;DR: Change spark plugs if you're changing your coils