Rattle under load when engine is hot

[jmystaki]

Heard back from the VW specialist... said the car was pinging.... don't know what to believe.....

[gtimk5]

The motors arent designed for 91 octane. Its a false economy not using 95.
Your car will go better and get a lot greater consumption using 95 octane.
The extra cost of 95 is a saving in the long run.
Pinging causes major damage to the head and pistons in virtually no time so I guess you have been lucky Biggles.
Andrew

[jmystaki]

I have booked the car in to have it professionally decarbonised with a PetroJect machine in the next 2 days

Will attempt to put a clamp on the exhaust tonight

I will update on the progress.

Cheers

[Jmac]

Andy thats right mate, 98 ron for sure and like i say most engines ping from time to time that you dont hear and the stuff you do hear is the worry. Drain the tank and fill with 98ron and fit a new filter and start a fresh. Crap fuel does them no good either.
Cheers
Jmac

[Pullstarter]

Good point on the crap fuel Jmac, copping a ****ty tank full is more common than most people think.

[Valver.]

I get a heap of Mk3 golfs in my workshop and none of them ping

Probably because you care enough to tell people what fuel to run, whereas most dud workshops couldn't care less

[gtimk5]

Thanks Stewie and maybe true mate.
I laugh out loud at the servos when I see all these people with new cars putting the cheapest available fuel in the $20000 ++++ investments.
I can understand it in XD Falcons or whatever but never in a later car.
Andrew

[Bora Sport]

My money is still on the heat shield. As an aside our Vento pinged on very light throttle at around 65-70 kph in fifth for years. If you put your foot down more (ie more load) the ping would go away which is the opposite to what I thought should happen. We have always used 98RON.

Anyway I changed the oxygen sensor it has never pinged since.

[jmystaki]

Ok, put a clamp on the exhaust down pipe, approx 100mm up from the joint where the cat connects (well the expansion chamber with the o2 sensor)... hope that's the right spot.

The drive to work tomorrow will put enough heat in the car to test if the outcome was positive.

Also ordered the VAG-COM usb cable (Ross Tech software) to run on a lappy to see if the sensors can show the knock sensor retard the timing...

[Biggles]

What's involved in connecting a PC up to the computer? Is there a port under the dash?
Ta

[gtimk5]

To connect, you remove the ashtray and slide the small panel above the lighter to the right. The diagnostic port is there.
Andrew

[jmystaki]

Still knocking/pinging after clamp.....

I noticed that the shield pressed onto the car around the exhaust down pipe was missing a locking washer which secure this onto the body...

I tried fitting an M5 and M6 nut in place, neither worked... I will try something else tonight.

Fingers crossed for the professional decarbonising process tomorrow.

[Biggles]

Thanks for the prompt reply gtimk5.

[Golf Loon]

Heard back from the VW specialist... said the car was pinging.... don't know what to believe.....

Get a second opinion from someone knowledgeable. I`d be happy to look at it if you wanna drive to the workshop at Campbelltown.

I dont see any Mk3s that suffer from pinging. If the petrol is right and there is no issues.

[sydVR6]

If it is pinging, 98 Octane fuel would cure it. This is the best way to diagnose.

Pinging is caused by the fuel in the combustion chamber being detonated by compression, before the piston has had a chance to reach top dead centre (TDC). 91 Octane fuel has a shorter carbon chain and therefore is more prone to detonation (pinging).

98 Octane fuel has a longer carbon chain and is therefore less prone to detonation. This is why Euro cars with high compression ratios need 95 fuel or better. If it still 'rattles' on 98, then you have eliminated pinging and can move onto something else.

The 'specialist' who wants to charge $1000 could have told you that before quoting you so exhorbitantly, so, save your cash!