Turbo car that's used regular!


I just bought an audi a4 quatro 3.0 turbo
found out it has a very slight ping, and the owner has been using 87 gas (manual says 91!)
the car has 55,000 miles
I can sell it back to the owner…suggestions for it’s future? I will of course wil only put in premium…
any feedback would be much appreciated especially if it’s decent! ha

If you can sell it back to them, do it; there’s no telling what else he might have skimped on. Could have been a champagne car that used a beer budget to get by.

Does the owner’s manual say that 91 octane is recommended or required? If recommended, you might try a tank or two of 91 and see what happens. If required, sell it back immediately. It seems strange that someone would not use the right octane fuel. It costs so little extra. If you drive 12,000 miles per year, premium only cost $4 more per week.

Pinging is possible in higher compression engines, which I expect is the case w/your car. One thing to check tho is the spark plugs. If they aren’t changed on the owner’s manual suggested schedule, the gap can widen and this can also cause pinging. It’s worth a shot.

Me, if reliability and moderate repair costs were what I was after in a car, I’d shy away from turbos. But if your budgets allows you some flexibility on reliability and repair costs and you don’t object to having to use 91 octane, then I bet your mechanic can easily solve the pinging problem.

I believe most cars since a specific date include a type of sensor which detects octane and adjusts to prevent knocking/pinging so running a car of this quality with lower octane may affect performance but may not be the cause of the pinging if the sensor is working properly. Googling knock sensor, etc. Should provide more details.

Turbo Audis pretty much require premium. Like others have said, if an owner of a premium car is routinely cheaping out on gas, what else has he cheaped out on? Audis take poorly to neglect.

And if you’re hearing pinging, the knock sensor is either inadequate to the task, or defective.

The use of regular gas would not concern me as much as the frequency of the oil changes and how heavy a foot the seller has.

If the price is right, have it checked out thoroughly, and put some 91 in it and see if it runs right. While it isn’t a great idea to use lower octane than recommended, the engine’s knock sensors and ECU likely have prevented damage from occurring. (but get it checked out)

More worrisome IMHO is if the owner has cheaped out on using full-synthetic oil and/or neglected oil changes.

If a car requires 91 octane fuel, as a turbocharged Audi surely does, to not use premium fuel is just crazy. I can’t think of a single reason a sensible person would use regular. Given that, I wonder what other required maintenance and repairs have been ignored. I wouldn’t buy that car.

The comment is hazy, but I read this as the buyer being a friend or acquaintance of the seller due to being able to return the car and apparently with no problem doing so.

The year and price was not stated but it’s possible the car could be a keeper; all depending.
It’s also possible that any pinging could be due to a sooted up EGR system and may not be related to the octane rating of the gasoline.

There’s also the issue of the timing belt and whether or not it’s due or past due. Some people get cold feet over the cost of something like this and choose to sell or trade the car rather than foot the tab for it.

Another question - it’s an Audi A4 3.0 turbo? I didn’t think there was such a beast, just the 2.0 turbo. If it is a 3.0 (v6) turbo, I’d think that would be the high performance version, even more need for premium.

what year is the car is it an a4 or s4?

The car is turbocharged and the owner has been driving it routinely using 87 octane and pinging. I’m with ASE that this is a dead givaway that the owner may not have been treating his car properly. That makes it a risky commodity. And prolonged pinging carries its own risks. Realize that the pinging you’re hearing is a shock wave out of synch with the power stroke, it’s the sound of a secondary explosion crashing against the one that’s supposed to be there. It’s a mild form of preignition, and pistons do not like to have explosions above them while they’re still finishing their ascent up the cylinder trying to compress the fuel.

As regards the antiknock sensor, that’s simply a piezpelectric accelerometer tuned to sense the aforementioned shock wave. It retards the ignition timing to try to compensate, but it is only compensating, not eliminating the problem.

The egr system could easily be a factor. It’s supposed to allow a bit of inert exhaust gas to be pulled in with the intake air to reduce the amount of oxygen a bit, keeping cylinder tems from gettting too high and preigniting as well as producing excessive NO2 (when the cylinder temps get high, nitrogen in the air gets bonded with oxygen and the Clean Air Act says that’s a no-no).

These cars are not noted for their low ownership costs even if not abused. Abused, they’re risky in my opinion.