Piston Slap: Breaking the Code: Opel Corsa Engine Troubles

Sajeev Mehta
by Sajeev Mehta

TTAC Commentator stingray writes:

My friend has a 2002-2003 Opel Corsa. In fact it’s “Made in Brazil.” I think it has GM’s family 1.6L 4 cyl engine. And here in Venezuela, this Opel is sold as the Chevrolet Corsa.

It’s throwing code 43: O2 sensor, lean mixture. Has a popping in the exhaust. I got the code using the MIL lamp and recommended that he change the air filter, fuel filter and clean the injectors. He did clean the injectors, also changed spark plugs, wires, coil and O2 sensor. Doesn’t know much about car fixing so got a bit PWNED on that. And the popping still continues . . . and the code too.

Sajeev replies:

I’m not sure which (American) OBD-II trouble code applies to the two-digit fault presented here.

So let’s speak in generalities, because “engine running lean” requires a loaded answer. Which makes me wish I was a mechanic by trade: a bad one that’s more than a little ignorant, too. Then, I’ll go buy a flat screen TV with my earnings. Because that’s how rich you can get by throwing parts at this problem.

But a fundamentally sound mechanic goes back to the basics, reading up on factory service information. Then he (or she, I don’t judge) checks these items, in this order: fuel pressure, TPS voltage, EGR position sensor voltage and proper operation of the EGR valve by using a vacuum pump.

Best and Brightest, did I miss anything in this diagnosis tree?

[Send your technical queries to mehta@ttac.com]

Sajeev Mehta
Sajeev Mehta

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4 of 16 comments
  • Anonymous Anonymous on Jul 31, 2009

    Before declaring it a leaky exhaust valve, I would ask if the popping is constant or intermittant? If it is constant a leak down test would confirm the valve issue. The popping/lean issue could also be the result of a simple vacuum leak.

  • Niky Niky on Aug 01, 2009

    See... if the O2 sensor was faulty, it could have thrown all the fule trims off... and the cheapest thing to diagnose would be to reset those. And the cheapest thing to fix would be a faulty MAF (a can of silicone-based contact cleaner works)... then you can work your way down to the more exotic possibilities... though a leakdown test isn't that expensive, there's no sense assuming the worst if the problem is occuring right after an O2-sensor throws a code.

  • Cnyguy Cnyguy on Aug 01, 2009
    @niky A) Randomly throwing parts at the problem based on cost is bad practice. You're never going to be sure you fixed the problem or just masked it. I cannot count the number of times a car came in on the hook with a lot of owner-replaced parts when the cause was something simple, like a corroded battery terminal. B) Silicone-base ANYTHING should not be used anywhere near an engine- the silicone will poison the O2 sensor in a heartbeat.
  • Niky Niky on Aug 02, 2009

    Granted... I didn't actually know that... thanks for the tip... although I do remove the MAF completely when I clean it and let the solution drip out... haven't had a blown O2 yet.