Audi S6, pinging/detonation

[KTM-Mike]

Hello!
I have an Audi AAN S6 1996 with some issues...

I hear pinging between 2700-3000 rpm when I accelerate on little or no boost (0.8-1.2 abs. pressure).
No ping over 3000 rpm and high boost.

100% stock engine. I have changed to 1,8t-coils and new Bosch F5DPOR, still pinging.
Compressiontest showed these values; 9,75-10-9,25-10-10,25.
IAT is fine(cold). Water/oil temp ok.Lambda is ok. Low EGT.
Only 98 high-octane in fueltank. New fuel filter also.

I have tested an aftermarket ECU (MaxxECU) with very retarded ignition and very
low lambda-values and it stills detonate!

Have anybody EXPERIENCED pinging from bad PCV-system or a bad turbo resulting
in oil in the intake air ???

Also, haven't checked fuelpressure/injectors, but the idle seems perfect...?

Is this normal for these cars to ping at these loads/rpm ??

/Mike

[UrS6 - IamS6]

I would change the spark plugs to NGK promptly to avoid any plug issues, as mentioned on this Forum.

[KTM-Mike]

Thought the plugs was only an issue at high boost.

And this is not an misfiring. I hear ping not misfire.

/M

[UrS6 - IamS6]

My suggestion is more to prevent you losing the engine to a broken spark plug, where the ceramic tip can break off.

As mentioned do a search.

Can't help re the pinging, but when I saw that you'd fitted new Bosch plugs, I felt obliged to post a comment.

We can both see what others suggest re the pinging.

Best wishes.

[KTM-Mike]

Ok. Thanks for the help.

/M

[mike74]

I had this issue on a previous motor...turned out the MAF wasn't working correctly. In that case very light throttle & WOT was ok but if you gave it some throttle in a higher gear at around 2-3000 rpm it would ping quite badly. Could be worth a look

[KTM-Mike]

/mike74

Thanks. I will look into that.

But I have also ping/det. with aftermarket ECU that is "speed density"-based system. MAF-signal is not used in this case.

If the MAF is defect, when on stock ECU lambda shouldn't be ok I think....

/M

[popdemonic]

if you're not sure your PCV is working correctly.you might try to pull off the X-pipe and check if there's some motor oil left in there and yes motor oil will defo effect your A/F but i don't think you should have any problems on stock engine ,turbo.Are you sure what you heard is detonation.i have had a couple sets of F5DP0R and broken the insulator.it caused the tick tick noise from the engine.IMO,i would check the spark plugs first.if they're still good,i will be throwing them in the trash though.that's my personal preventive plans.i'm not happy with stock spark plugs.Maybe i have most Bosch spark plugs failures than anyone in the world lol.

[KTM-Mike]

/popdemonic

Spent an hour reading about Bosch-plugs......jesus, I will replace those plugs ASAP!!
NGK BCPR7ES work fine?

Will check the PCV. Maybe it's not breathing right.

I've just put new Bosch-plugs in there. Maybe 20km with new plugs & coils.
Had the same noise before I replaced the plugs & coils.
Did you hear the tick-tick only at certain rpm's also ??

/M

[UrS4boy]

OE 3B, AAN, ABY and ADU Exhaust Components

Would you consider the possibility that what you are hearing is a metallic rattle from the heat shields on the "Y" pipe that tend to rust off?

Exhaust info: http://forums.quattroworld.com/s4s6/msgs/196904.phtml



This one shows the very last of the shield that originally covered both branches of the "Y" pipe going to the catalytic converters:

[KTM-Mike]

There is no heatshields left on the car.

[KTM-Mike]

Today I replaced the spark plugs to NGK BCPR7ES.

Didn't stop the pinging...

/M

[UrS6 - IamS6]

No, but at least your engine is not in danger any longer, best wishes with the pinging though.

[popdemonic]

if you are sure what you heard is detonation why don't you try to fuel up with higher ron fuel and running?
if you re having stock car i don't think it 's pinging mate.my country has E10 and been running that fuel for years.
my country weather is mid 30c all year though.my intake temp is 60-70c.it's more prone to be pinging than any of you in states or europe.

[newsh]

If it still did it with the timing retarded then it's unlikely to be detonation. Unless you've got massive carbon build up which is glow plugging..

Could be a small end, or piston slap or maybe a sticky lifter.

Proper pinking always happens at lo rpm lots of throttle, or midrange and lots of boost.