I am not a mechanic, but fairly handy. I bought a D2 as a project and have done quite a bit to get it running, but am still battling some codes that are preventing me from passing emissions here in Atlanta.

Current codes are as follows
P0171 Bank 1 too Lean
P0174 Bank 2 too lean

I have gotten the following other codes as I have tried to track this down (maybe they will help shed light)
P1174 Unknown Diagnostic Code
P1172 Unknown Diagnostic Code
P0733 Gear 3 Incorrect Ratio

I have a wifi obd connector and use DashCommand app on my iPhone. I think I can read values for most everything with it if someone can help me know what to test/look for.

Thanks!

 

Maf sensor!

 

Use a genuine bosch. Your symptoms are classic MAF related.

 

Maf - BUT they didn't tell you why. If you look at the left rear corner of the airbox lid, you will find a tab bent over letting unfiltered air into the engine, this will ruin your MAF and may mess up your IAC.

 

Have you checked for vacuum/intake leaks?

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I did look up the codes and saw they were just saying it's lean. Not sure how to check for vacuum leaks or where they would be?

 

One quick way to determine if the lean codes are caused by vacuum leaks is to watch your fuel trims. Start the engine and check your readings at idle. Then rev it up a few times. If the lean condition is caused by a vacuum leak, the fuel trims will start to correct when the throttle plate opens.
If it's caused by something like low fuel pressure, the fuel trims will go more positive, or farther from zero.

 

If does point to a vacuum leak. how can i locate it?

 

MAF. It could be Vaccum leaks but my money is on the MAF sensor. The fact that both sides are lean and the incorrect gear ratio code. You could try cleaning with some CRC MAF cleaner.

 

Sometimes you can hear the leak, if you're lucky. Try opening the hood and listening for a hissing sound with the engine idling. If that doesn't work, you can watch the fuel trims while spraying some brake cleaner or propane, or anything flammable around the vacuum lines, intake gaskets, etc. When you find it, you'll see the fuel trims change.
Or, if you have access to a smoke machine, that's the best way to find leaks. You can also make one. There's plenty of info on that around the internet, just search for it.


Shaggy makes a valid point here too. The MAF is notorious for throwing the "wrong gear ratio" codes. I would start by cleaning that. Put a little cleaner on a Q-tip and gently wipe off the hot wires. I would avoid dousing it with cleaner. It doesn't clean them very well and it takes forever to dry.