Chunib

Finally starting to drive and care for the 8 I bought last year now that the snow is gone. I feel like I have had no issues with the car, and its been running beautifully (To the best of my rotary knowledge).

Thought it wouldnt hurt to check the CEL readings just incase theres something that I was missing. (Im basically brand new to rotaries, wouldnt be surprised). I got 2 codes, and im just curious how big (or little) of a deal they can mean. Only thing I could see as being potentially not normal with my car would be when its idling, usually after I just start the car, a decently loud fan sound (vacuum sound?) comes from somewhere in the engine for maybe 5 seconds or so, then repeats maybe 20 or 30 seconds later. I reckon this could be a fault and is causing the CEL codes.

OBDII READINGS:
P0171 system too lean, bank 1
P0410 secondary air injection (AIR) system -malfunction

My knowledge of cars is relatively slim, but I would assume checking the sensors for these would be a good place to start. Looking for diagnosing tips, but any help would go a long way.

edit: its a stock 04

Shaozhou Zhang

Just ignore P0410 if your state does not do emissions.
P0171, on the other hand, is a possible vacuum leak (the most common I see on forum) that can impact your drivebility. What's your Maf reading when the car is hot with all load off? should be 5-5.5 gram/second, anything lower than a 5 indicates a vacuum leak.
You can refer to the FSM here for diagnostic procedure if your MAF reading is normal.

Loki

iTrader: (1)

The howling noise is the secondary air pump which is what P0410 is about. The pump running and making some noise shortly after startup is normal. The P0410 isn't. You could just live with it, but it does serve a purpose and having it can help keep your catalytic converter alive longer. The pump feeds air into the exhaust to help warm up the cat faster... The sooner it warms up, the less it fowls with fuel. If it was my car I would figure out what's wrong and fix it.

P0171 is a lot more unusual, follow the advice above.

Chunib

Getting a reading of around 3.2-3.4 with a hot engine. Definetly a vacuum leak then?

Loki

iTrader: (1)

And a big one.

Shaozhou Zhang

That's a really really big one. In fact you don't seem to have any drivability issue is mind blowing. Fix it and you probably notice your car behaves a lot beter.

Chunib

I went looking around at all the lines. Tried a fog machine on it to see if I could find the leak myself. Lemme preface this with I am not a car guy, I do my own oil changes and thats about it. This is just speculation on my part but I assume this is where the "leak" is.




This is where all of the fog was coming out of. I couldnt see any other spots. I guess I could have tried plugging that spot up and checking elsewhere for any other leaks but like, I feel like there should be a hose here no? Am I the dumb one?

Loki

iTrader: (1)

That's the VFAD nipple. It should have a line going up to the front of the intake tray, connecting to a solenoid. If you don't have the stock intake, and no VFAD, you can just cap it.

Chunib

Just capped the VFAD nipple and cleaned the MAF sensor. One of the screws on the MAF sensor was a little stripped and didnt screw in nicely, so I replaced that. Checked inside the Air Filter and looked in relatively good condition. One of the clips holding the air filter together was inside the air filter bay. Last owner must have accidently dropped that in there. Cant tell if there is any performance benefits from all that, but at the very least, CEL code P0171 is now no longer coming up, even after a 60km drive. The MAF readings with a hot engine idle is around a 4.2g/s average, which is definetly an improvement over what it was initially.

I'll look more into P0410, but if its just an emissions thing, then it's not too big of a concern at the moment.

Loki

iTrader: (1)

Still a bit low, maybe you have multiple leaks. What the ltft and stft on the same warm idle, and is the idle near 800 rpm?

The airpump protects your $2000 cat, so while it is emissions, may still want to fix that P0410 if you still have a cat.

Chunib

Short term is wavering between 2% and --2% when warm idle. Long term is a very stagnant 11.72%. If I remember correctly, short term was way different before all the changes in my last reply, like 20%~

And id say it hovers around 800, it doesnt drop super low, maybe down to 750 or 700

Loki

iTrader: (1)

Ok that lines up. If you add another 12% to 4.2, you're around 4.7 g/sec which is reasonable. There's still a 0.5g/sec leak somewhere.

Chunib

Figured I'd go look at the fuses, Air Pump fuse was blown so I replaced it (Not sure why I didnt think of doing this beforehand, I'm dumb). Solved the P0410 code. No more CEL codes. I'll keep trying to figure out the rest of the vacuum leak, but for now everything seems to be in order.

StephZoom

Don't laugh but when I had the P0410 it was caused by a bad quality cold air intake pre-filter. I tried to save a buck by buying this instead of the genuine AEM:
I removed it, drove a few miles, and the CEL turned off!

So, if you have a pre-filter, try removing it and clean your filter while at it to make sure that's not what's starving the car of air.

Also, my OBD scanner reports the MAF value in lb/min, not g/sec. For me, it's 0.61 lb/min at idle. So, 4.6 g/sec seems like a decent value. I don't think you have another leak other than the old age of the car. :-)