UK-POLOS.NET - THE VW Polo Forum

My tale of woe - on Friday night i was driving home from work, ragging it a bit and the engine management light comes on, with a noticable drop in performance... oh dear - better slow down and start sweating... 10 miles later and the car misfires after about 4.5 grand... oh dear oh dear...

As my car was booked in for a service today, I decided to leave it till today to get the problem fixed, started her up and she doesn't want rev past 3 grand, and is doing a good impression of something from scrapheap challange (brown trouser time). Took it in this morning at 8 and at 3 o'clock after working on the car, phoned them and they still haven't worked out the problem...

They'd put it on the VW diagnostic machine (it isn't a main dealer but a specialist) and it came up with 6 engine management faults, 2 of which they solved quickly, the rest of which all point to a timing issue which they're guessing is a cam positioning sensor problem.. Problem is, if the timing was well off (which it was by the sound of the engine note this morning), at least 1 cam might be dead, and i may be looking at bent valves...

Something tells me this ain't gonna be cheap, and that this may well be the last VW I ever buy...

Watch this space

Let us know how you get on mate...

The bloke who bought my GTi sent me an email last night telling me that his won't rev over 5k and it takes ages to get there... He said it feels like there's no power...

Sounds like a similar problem doesn't it...

He mentioned that it feels like there's something limiting it revving over 5k... Dunno about missfiring though.

Anyway, let me know so I can pass on the details to him.

Fuel starvation to me... If the engine was broke you'd hear it clattering around.

There's a few things I recall that caused this on my last car.

Firstly, the fuel filter could be blocked.

Second, the throttle position sensor has either worn out or developed a contact fault - these often have a carbonised contact and if you spray any solvent like WD 40 in the air intake, then this is immediately destroyed.

Third, the ECU is faulty.

If the timing is out, then it's more likely cos of the air to fuel mix and not usually cos of the timing actually changing. The ECU reads these sensors and adjusts the engine accordingly.

That's my experience of this kind of fault. Hope this helps.

I had an intermitting fault with the car not reving above 5K it was like hitting the rev limiter, it was usually around 20 mins after being started from cold. If you turned the engine off and restarted it was fine. I think it may have been the engine still being in choke mode and not sensing it had warmed up. No fault was ever found at service time.

That would have been the Thermo-sensor (green one) on the water pipe going into the engine.

Cheers for the advice guys, unfortunately the garage have already covered those points - hence the confusion over what it actually is...

Fuel Filter has been replaced, throttle body taken off and cleaned out, they've looked at the position sensor and ruled that out... I'm, not sure if the ecu has been checked but i'd assume that they've covered it...

We'll find out soon because it's gonna be looked at all day tomorrow to find out what it is....

Oh, and the engine was making some funny noises as well, not quite a clattering, but not good... Kind of a ticking noise on overrun, it sounded like the noise injectors make, but louder..

The only thing that i find points agains internal damage is that the car idled fine, with absolutely no odd noises at all

Oh well - all will become clear tomorrow - I can hardly wait!!!

Oh, that reminds me - anyone want to buy a polo !!!

If it's running on, then it is likely to be the throttle position sensor giving false info to the ECU and making it throttle back above 5K or run on when switching off. That would be my take on it. The tapping noise is the mixture of air to fuel being out - it's pinking and the ECU is advancing the engine too much.

..removed the spark plugs? Are they damaged?

I once had a spark plug drop some electrode enamel into the piston pot and that made a real loud clatter cos it doesn't go out of the outlet valves.

If the engine gets hot, then the enamel gets hot and then it misfires all the time as the fuel mix in the pot is being continuously ignited by the hot enamel!

That was a real experience trying to get the broken enamel out of the spark plug hole!!!!

Spark plugs have just been changed so who knows - unfortunately i'm at the mercy of the garage now, as it's stuck there till it gets fixed.. I'm gonna ring them in a minute to see when it's actualy getting the work done..

I may have mislead you morrismen, it's not running on, it's making a rattling noise just after I lift off.. Also, thinking about it now, it was making a slight noise on application of the throttle..

Progress - or lack there of

Just phoned the garage - More bad news.... It looks like the cambelt has slipped!?!? So they're going to take that out and investigate further...

Methinks a re-build is on the cards somehow!

They can't tell me a price because they still don't know what 's really wrong - i asked for a best situation worst situation and the answer was...


£390 for a cambelt and waterpump if the waterpumps gone...

£3000 for a brand new engine...


She said it was probably going to be somewhere in between!

Looks like my next can is going to be an L reg micra at this rate, rather than the 200sx i'd been planning!

Can anyone recall the part that goes that makes the Cambelt slip/brake and damage the engine... some have said they get it replaced before it goes... is it the cam tensioner or something like that?

ttaw2 wrote:Progress - or lack there of

Just phoned the garage - More bad news.... It looks like the cambelt has slipped!?!? So they're going to take that out and investigate further...

Methinks a re-build is on the cards somehow!

They can't tell me a price because they still don't know what 's really wrong - i asked for a best situation worst situation and the answer was...


£390 for a cambelt and waterpump if the waterpumps gone...

£3000 for a brand new engine...


She said it was probably going to be somewhere in between!

Looks like my next can is going to be an L reg micra at this rate, rather than the 200sx i'd been planning!

Ouch - when was it last replaced......

New engine option isn't funny if the tapping noises were valves clipping the pistons then

Head gasket, bolts, seals, gaskets are the minimum you'll get away with.....

Not nice at all - I know Vauxhall tensioners are notorious for seizing and wrecking belts I wonder if VW's have a similar issue?

morrismen wrote:Can anyone recall the part that goes that makes the Cambelt slip/brake and damage the engine... some have said they get it replaced beforem it goes... is it the cam tensioner or something like that?

Yeah, thats the cambelt tensioner. I've had that go on my GTi, under warranty. Although in my case the car still drove normally, just sounded terrible when coming on or off the throttle due the belt's movement I presume - tightening and slackening? Anyway, thankfully the only damage was to the cambelt assembly which has been fully replaced under warranty. Its a costly job outside of warranty - I think it might even be an engine out job?

Cambelt replacement is supposed to be at 60,000 miles. Mine went *pop* at a little over 51000.

HTH?

Cheers again guys - i'll ring the garage and see what they say...

Just for info, the car's only done 44,500 miles.....


"If only everything in life was as reliable as a volkswagen"... Ironic!