V6 Pinging right between coasting and acceleration

Are you that sure it's valves? Because your symptoms sound suspiciously "on-boost" - and if the turbo is knackered maybe you're just hearing it's death rattle...

Some of the V6s had problems with the timing belt tensioners. Not sure if yours is one of them but this causes rattling sounds.

T> I have 1995 Audi 90 with the 12V V6. I bought the car used 4 years

Err... what turbo?

Yea. Trust me, there's no turbo. :-(

'bellfamily')

Sorry, totally missed it...

Make sure you're using high-Octane gas.

JP "Gene" escribió en el mensaje news:Xd0kb.863$ snipped-for-privacy@newsread1.news.atl.earthlink.net...

Or alternatively, retard the timing a degree or two. Though that will have performance consequences.

Cheers,

JP Roberts wrote:

Yup. You're hearing something else. The earliest Audis to actually have any *power* (and yours is in this vintage - the late '80s turbos,

It *starts out* sounding exactly like detonation (pinging), but if you think about it, it occurs at precisely the wrong times. Detonation occurs under engine *load* and this doesn't.

It is definitely not the valves because it comes and goes so quickly. Valve clatter is constant over a wide rpm range (although it can go away when the engine warms up if the clearances are small) because the clearances don't change that quickly nor, in the case of hydraulic lifters, do they pump up and empty that quickly.

You're left with this looseness in the driveline as your only probable cause, and the symptomatic sounds match the theory exactly - when the driveline is vascillating slightly between acceleration and deceleration. It gets progressively worse, depending on how much stress is put on the joint, but it does so fairly slowly and even when it's making quite alarming noises, it doesn't really keep the car from being driven. It's mostly embarassment. Contact Jim at Blaufergnügen

-- C.R. Krieger (Been there; done that)

Something grates everytime I see this - surely it should be Blauvergnügen?

Sorry; he spells it this way. As a born-&-raised Wisconsin boy, his German spelling and grammar isn't very good; but it *is* a made-up word, after all.

-- C.R. Krieger "Ignore 'em, m'dear; they're beneath our dignity." - W.C. Fields

I am using 92 or 93 octane, nothing but.

Adjust the valve timing? There's no way to retard the ignition timing that I know of.

Gene

Wow this thread is still on a server?! Anyway I fixed the pinging....and yes, it really was pinging, not drive-train noise.

I pulled the heads and replaced valve guides and all the gaskets. The pinging I detailed in this thread is now completely gone, replaced by much better highway accelleration. I'm guessing that oil being sucked past the valve guides was fooling the O2 sensors into thinking the mixture was rich. Also, the valves may have been clattering around a little in loose guides.

Gene