[steven bora]

Can anyone help?? I have had owned my 1.6s Bora for 7 weeks now and i`ve had it back to Verve (dealership)in Glasgow 7 times.I told them there was a rattle from the engine after i had changed gear or when i was going up hill,they changed the gearbox oil ,then they found a problem with the gear linkage,then they found a flat spot and cleaned the throttle something?? Now they have told me it`s something called "Pinking" and the only way to get rid of this is to use Premium Unleaded.Can anyone give any advise on what this could be or what to do next ...Thanks

 

[darthmal86]

yep dude ive got that problem too. i told them about it when my car went in for its first service and they told me to use premium unleaded too. but still hasnt changed.

and ive still got the flat spot []

 

[Stevie P]

The problem is not unheard of on 170bhp V5s, either. I don't think it's any coincidence that both the 1.6 16v and 170bhp V5 came out around the same time (late 2000/early 2001).

I reckon it's down to ECU software. It's quite simple, the knock sensors should stop the engine knocking. If they don't, then either they're not working properly or the ECU is processing their inputs correctly.

This business of having to run the car on "premium unleaded" (which is the normal stuff, anyway) is complete rubbish. Strictly speaking, you should be using Optimax which is 98 octane. However, the Australians get the same engines and can run them on 91 octane, so you should certainly be able to run them on 95 octane with no pinking whatsoever.

There may be a software update available for the ECU, which the dealer should be able to load for you. There's no harm in asking, though it might be wise to check with VW customer services first, in case the dealer denies all knowledge.

 

[pope1]

I've got that too on an AGU 1.8T. Started doing it when I went to pick up the car from the last service. Definitely was not doing it before. Recently I thought that it might not actually be pinking but was a problem with the dump valve. Fixed the dump valve problem but the noise remains. In my case the noise is quite subtle at times (and I'm not always sure that it is pinking) so I'm also going to check out the turbo nut/bolts and the downpipe nuts just to make sure that the problem is not due to a slight leak there.

It's a bit of a long shot but you could also try checking out the condition of your dogbone mount - it's the lower rear gearbox mount. Now I can't imagine why a worn one of those should produce a noise like pinking but I'm trying to cover all the possibilities and I believe that mine is worn as well.

 

[darthmal86]

how much do VW charge for a ecu software upgrade?

also are there any upgrades after 2002(52 reg)?

cos i really wanna get rid of this pinking

 

[pope1]

My car NEVER did it before so I don't reckon it's software in my case. Vag-com does not pick up any faults but I reckon that something much be wrong other than the software.

 

[steven bora]

Thaks for your advise .Does anyone know if a new ecu would solve the problem??

 

[bungle]

Think you'll find the 'pinking' is actually detonation due to the very high compression ratio of the 1.6 16v (I think the V5 has a high compression ratio also). It's all in the cause of a cleaner emmisions I'm afraid and is a 'feature' of this engine. A higher octane fuel such as Optimax will help as the fuel/air mix is less volatile and therefore less prone to pre-ignition under compression.

 

[pope1]

Although I don't know anything specific about the VW 1.6 engine I have a major problem accepting that pinking is a "feature" of any modern processor controlled engine. Pinking is not good and left unchecked will do damage to an engine in the long term. In the days before knock sensors and electronic engine management some cars (notably the Italian ones) had high compression ratios in order to produce more power and pinking was not the order of the day providing that the timing was adjusted properly and the fuel was of reasonable quality. Modern engines have knock sensors and variable timing that is controlled electronically so that they can operate close to the limit. That's why we can run turbos with the kind of boost pressures that we have now without detonation occuring. Sorry, in my humble opinion if a modern car is pinking something is wrong and, once again without knowing any of the specifics of the VW engine, I'd have to wonder whether the knock sensor(s) is/are working properly. The 1.6 has one sensor, the 1.8T has two. In my case I believe that the noise I am hearing IS pinking rather than any of the other things I suggested earlier and I'm going to be talking to my local VW dealer about the sensors in the next day or two.

On the question of fuel, using higher quality fuel or an cat-friendly octane booster should help but my question is why should you have to do that if the car is running properly? Once pinking starts to occur, the knock sensors should pick it up and the ECU should retard the ignition sufficiently to eliminate it.

Final comment and then I WILL shut up. I'd only change the ECU as a last resort and then I would need some convincing that changing it would really cure the problem. I know that some of the 1.6 Boras over here had engine management issues and had to have a software upgrade but I think that applied to the automatics only and the manual ones were OK. In any case I don't think that had their ECUs replaced.

 

[bungle]

As I said it's a 'feature' of this engine, I'm not talking about the 1.8T. That doesn't mean I'm saying it's right! I spent ages trying to get VW to address the issue with my previous car (including ECU firmware) but after many visits to the dealers and trying many other similar cars had to accept that all 1.6 16v's do it to varying degrees.

The issue seems that modern small engines are tuned for minimal emisions rather than performance and therefore run very lean mixtures in order to get a very hot burn. Couple this with the high compression of the 1.6 and they will be more prone to detonation. Knock control can't do anything about detonation as it's not a timing issue.

I got shot of my 1.6 in the end as aside from the pinking it was shockingly noisy and rough. My current 1.8T 180 is in a different league...

 

[Stevie P]

I'm sorry Bungle, but I have to disagree with you there. Detonation is a timing issue, and is precisely what the knock control system is supposed to be addressing. Pre-ignition should not occur in a naturally aspirated petrol engine unless something's seriously wrong. It is more likely to happen on a turbo engine, but again, only if something's seriously up the spout.

Detonation, while not as serious as pre-ignition, will gradually cause physical damage to the cylinder head. If you want to tell whether it's doing any damage to the engine, checking the condition of the spark plugs will give you some clues. If they look fine and the electrodes are intact, then there's probably not much to worry about.

The furthest I've got with looking at the problem is by using a diagnostics tool, I've noticed that the knock control system is retarding the timing on two cylinders more than the others. Now, I've done a compression test, and the (minimal) differences in compression between all the cylinders do not explain the differences in retardation of the ignition timing. I think the knock sensors are OK, because they were picking up excessive knocking on a particular cylinder and that went away when I replaced that cylinder's ignition coil.

I've tried swapping coils between other cylinders, but it's still the same two cylinders having their timing retarded by 5 or 6 degrees more than the others. The spark plugs are fine after 27000 miles, so nothing's seriously wrong, but something isn't quite working as it should.

 

[pope1]

I think that Bungle is correct in saying that the combination of a lean mixture and high compression is MORE LIKELY to cause detonation. However, I would still believe that if the engine is operating correctly you should not be getting detonation or pre-ignition.

Stevie P - thanks for mentioning spark plugs. I'd completely overlooked those in the scheme of things and will have a look at mine.

 

[Stevie P]

Quote: posted by pope1 on 27/08/2004 11:00:07

I think that Bungle is correct in saying that the combination of a lean mixture and high compression is MORE LIKELY to cause detonation.

Yes. It may have looked like I was disagreeing with Bungle's whole post, and I apologise for that, as I agree with everything else he said. The 16v 1.6s are notorious for pinking (i.e. detonation). It may be that VW haven't come up with a solution yet, or simply that they don't consider it to be a problem. A cynic might argue that they don't consider it to be a problem as long as no obvious engine damage occurs within the warranty period, but I couldn't comment on that.

Perhaps you should ask if anyone has a 16v 1.6 that doesn't pink.

 

[pope1]

Shocking that it should be like that in this day and age[:O]

 

[bungle]

I stand corrected on the knock control. Getting myself confused between pre-ignition and detonation it seems.

Incidentally, the knock sensor(s) on my car were replaced as part of the work VW carried out in trying to fix my car but to no avail.

I think my car suffered bad enough that sometimes it dropped into what I think was 'limp' mode. Although it had about half the normal performance, the pinking did at least stop!

 

[steven bora]

Bungle.. You seem to have had had the same problem as me .Is there any advice you can give me on how to confront my dealer? Is there any solution? or do i ask them to exchange the car for another model?.

 

[bungle]

If your car 'pinks' as badly as mine did then I don't think you'll have a problem convincing the dealer that there is an issue.

My dealer was reasonably helpful (especially given that my car was a personal import) and went through a process of elimination replacing the ECU, updating the firmware on the ECU, knock sensors etc. but all to no avail. It was only when I continued to nag at them that they started using the old chestnut 'they all do it'. Unfortunately after testing several others it appeared that the dealer was right and it seems that most 1.6 16v's pink to some degree.

As my car suffered from numerous other problems such as intermittent power loss (does yours do this?) and was very noisy I decided to get rid of it. My next step would have been to raise the issue with VW UK and demand a VAG engineer inspected my car and justified the problem.

Best of luck.

 

[iaincondliffe]

I've had exactly the same problem on mine. Had the car from new and its always been there in varying amounts. It had a new ECU at 12 months, for what reason it was never explained to me, a new lambda probe and also a new EGR valve at Easter. The EGR valve has reduced pinking by a considerable amount and its rare that it does it now. The cars done 47,000 by the way. Oh and its always been VW assist who have been most helpful (maybe its because theyve not got a big desk and fancy coffee machine to hide behind.....)

 

[bungle]

I forgot, they also replaced the EGR valve on my car (several times!)...

 

[steven bora]

Cheers Bungle ,and everyone else ,for your advice ,I`m going to try premium unleaded for a couple of weeks to see if it help`s... but for now i`m going to send a letter into the dealer M.D explaining what advice i`ve had (including printouts ). Hopefully they will take notice and come with a solution or advice what to do next .If anyone else has any suggestions i would love to here from you --thanks