2010 Audi A4 Quattro, 2.0L TFSI engine, automatic transmission, 180,000 km.
Friend bought this car used 2 months ago from a private party. The check engine light comes on with a "bad smell." I had another friend's Jeep stuck in my garage, so I went to their location to take a quick look, and found the following:
- check engine light is for "catalytic converter efficiency too low"
- tail pipe is filthy black
- one of the fuel injectors has wax crayon squiggle on it, suggesting it came from Pick-n-Pull (self-service junkyard)
- I turned the check engine light off (erased the code), they went for a moderate drive, it did not come back on
- the car drives normally, sounds normal, has good power
I got my other friend's Jeep out of the garage, so this friend brought their Audi over for a more in-depth look. I found the following:
- check engine light is on again, found no codes, so cleared it again
- spark plugs were oil-fouled
- spark plugs were the wrong gap for the factory spec (0.023" instead of 0.032")
- coolant is clean
- found an ignition coil in the glove box ("Wait, that's not where this goes"), as well as "some sensor part"
- replaced spark plugs with new ones of the factory spec with the factory gap, the car shook violently at idle and the check engine light was blinking ("That light looks angry")
- turned the car off, checked all electrical connections, turned the car back on, it was still angry
- removed the new plugs, re-installed the old ones, turned the car on, it seemed happy now
- tried checking the oil, couldn't find a dipstick anywhere. There's a tube that looks like a dipstick tube, but there's a removable cap on it and no dipstick. Went out on the street, stole a dipstick from another car, shoved it in, no motor oil to be found. Googled why this Audi doesn't have a dipstick, learned about the electronic oil level indicator, turned it on, it was blank and yelled "Add engine oil immediately!" Looked at the oil cap, it doesn't say what grade of oil to use. Back to Google, it says 5w40. Bought a big jug, poured half of it in, the oil level started registering. Topped it up, this thing drank the entire 5 qt jug. ("Where are you putting all of this?")
- Called my friend, told them to pickup the car (they need it for work, and I need time to figure a few things out)
- friend says the car got an oil change "2 or 3 weeks ago." I suggested that the oil may not have been topped up, they said they went back a few days after the oil change because the oil warning indicator came on and the oil was topped up.
- The lack of motor oil is likely related to the known oil-burning issue with this generation of the 2.0 L TFSI engine, and probably why the tail pipe is black and probably why the catalytic converter runs below efficiency. I was planning to do a compression test, but this thing doesn't have a key, it's a "jam your transponder in here and press the brake if you wanna start". After disabling the fuel pump, I tried starting the engine to bleed whatever fuel pressure was left, and this thing kept cranking and cranking and cranking. I yelled at it to stop, but that didn't work. It eventually got bored of this and stopped cranking. I ain't doing that again unless somebody tells me I can yank the transponder back out and it will stop this thing from cranking when I no longer want it to.
New out of the box factory-spec spark plugs make the engine angry, but oil-fooled wrong-gapped spark plugs make the engine happy. The "wrong gap" is what I found listed on Google "if you are chipped," so here's the question:
How do I find out if this car has been chipped?
Research into this suggests that there are 2 ways to "chip" this engine: piggy-back systems and plug-and-flash systems. I didn't find an obvious piggy-back system under the hood, but the cowling near the wiper blades doesn't look happily attached, like someone's been in there. I believe that's where you access the ECU? Are there piggy-back systems that would attach near there? If it was a plug-and-flash operation, those are typically done through the OBD2 connector and leave no physical trace. The OBD2 connector is free, that's how I read and cleared the catalytic converter code. How would I find out if the ECU has been reflashed? I have since learned how to access a "hidden configuration menu" on this car (press "Car" and "Setup" together), I haven't tried it on this vehicle yet, but is there something in there that could tell me if the ECU has been reflashed? A firmware version number maybe?