Lean Running 01 D2 - Need Help

[StusRover]

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!

 

[ptschram]

You need a mass airflow sensor

I probably have one in stock

 

[StusRover]

In this process, I swapped in the air box back to the intake including the sensor even though it wasn't erroring before. I needed the duct after the sensor and this was already all together. I just swapped in my old sensor to see if it changes anything. I'll let you know if that doesn't have any impact.

Is there any way to test the sensor or is it just replace if you think its the issue kind of part?

 

[ptschram]

Based upon those DTCs, it's the MAF sensor.

 

[96discoI]

and don't ever put an oiled air filter in it again

 

[discostew]

You need a mass airflow sensor

I probably have one in stock

You can tell that from where your sitting? Pretty impressive.

 

[StusRover]

I have replaced the MAF Sensor and now I am getting the P0174 code. Is this more a vacuum leak or an o2 Sensor issue?

 

[riceybean]

I'd look for a vacuum leak too. I found a few on mine recently, intake tube was cracked, brake booster line at the intake was leaking and I missed a hose clamp on the valve cover breather. Cleared my codes and they haven't returned.. yet

I was throwing 4 codes, o2 sensor, MAF, misfire on 2, 5 and 8 and a lean code.

 

[seventyfive]

I have replaced the MAF Sensor and now I am getting the P0174 code. Is this more a vacuum leak or an o2 Sensor issue?

If you don't have access to a smoke machine your going to spend a lot of time chasing parts.

Personally I'd lean towards fuel injector seals or the breather hose on passenger side valve cover.

In the future when you get both banks lean and a trans fault it's usually the MAF. If you unplug the MAF then start the engine and the engine runs replace the MAF.

The oxygen sensor is reporting the lean condition, in other words doing its job. Can you watch the O2 signal? Does it change voltage? Watch both oxygen sensor voltages and remove the oil cap, do both go lean?

 

[discostew]

If everything else checks out and you do a smoke test like seventfive mentioned then you could have a fuel problem. When ethanol content gets above the 10% it should be the fuel trim goes lean.

 

[seventyfive]

If everything else checks out and you do a smoke test like seventfive mentioned then you could have a fuel problem. When ethanol content gets above the 10% it should be the fuel trim goes lean.

Combine ethanol and 89 octane from cut rate fueling stations! I think ethanol also reduces octane by 2-3 points especially when you factor in a poorly operating crank case ventilation system. The amount of oil entering the manifold factors in as well.
There has to be a Rube Goldberg smoke machine set up somewhere on the inter webs....unless you have deep lungs a couple packs of pall malls!

 

[StusRover]

Thanks guys I'm on the lookout for a smoke machine. I'm hoping a friends shop has one.

I put premium gas in it but it sat quite a bit for the previous owner. I'm assuming but fairly certain he didn't use premium. I have obviously worked through several tanks by now but is there a cleaner/additive I should consider adding?

 

[discostew]

Ethanol has less BTU's. In southern Illinois they used to sell 20% and call it super unleaded. It would always cause lean faults. Octane is an additive that slows the burn. High ethanol content also slows the burn and kind of does the same thing as octane by lowering the heat in the combustion chamber.

 

[seventyfive]

I use stabil in all my vehicles. If the vehicle sits, for even a week, make sure the tank is full and add stabil. Once you get into the habit and have a stock pile of stabil it becomes second nature.
There is an additive called http://www.biobor.com which you should be able to find at boating stores. My sailor friends swear by it.

 

[StusRover]

So my friend ran a smoke test at his shop today and didn't find a leak. Which most of the time would be a good sign, but now I am back to square one. He said his smoke machine isn't the $2k one that some shops have, but its always worked for him. He didn't check around the injectors though. So do I take it to a more "rover" shop I don't know to get them to retest it or is there something else I should look at?

 

[discostew]

You might want to do an injector balance test to see if they are restricted. Sometimes I go as far as taking the fuel rail off to see the spray pattern on each injector. I say that because you mention it may have sat for a while. Ethenol gums up really fast when it sits.

 

[StusRover]

hmmm thats an interesting idea discostew.

I ended up taking it to a LR/BMW local small shop and they ran diagnostics and a smoke test and it didn't throw any codes for them and didn't leak for them either. However after leaving the shop after putting another 30 miles on it (to get enough to clear emissions testing) it started throwing P1174. I cleared it and drove another 20-30 miles today and got it again. Does this still lean towards injectors? or should I be looking at something else?

 

[squirt]

This was mentioned earlier, but have you been able to observe O2 activity in real-time? Are the sensors switching like they should?

Chances are, the shop "running diagnostics" means they checked for codes and found none, then smoke-tested at your request and sent you on your way. I'd be skeptical about the O2 sensor on the bank that's related to your lean code. Even if it's not showing much abnormal activity, I'd try swapping to the other side and see if the issue follows.

 

[discostew]

Squirts right about what happened over at that shop you went to. You don't have any exhaust leak on that bank going lean do you? Its not a terrible idea to switch the o2 sensors side to side. But with no o2 sensor fault it might not be worth damaging a sensor or having one seized in the pipe. Sure sounds like a vacuum leak to me. You almost need to do some of this shit yourself, nobody but you really gives a shit about your old truck. What kind of fuel pressure do you have?

 

[StusRover]

I don't believe I have an exhaust leak. Sounds fine to me. Yesterday while driving it to try to watch the O2 activity, It threw P0150 a couple times. I looked in Rave, but don't understand if this is a fault with the actual sensor or what it's connected to? At this point I am thinking I need to replace the o2 sensor atleast the RH Sensor 1.

When watching the O2 activity, what should it look/read like? What are normal values, so I know if its out of range?