2000 Saab 93 P0171 lean code

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Old 08-26-14, 04:46 PM
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2000 Saab 93 P0171 lean code

I haven't posted for quite a while but I am looking for some confirmation or other ideas to get rid of the fault code on my wife's car. the Saab only has 50,000 original miles on it. Kind of a survivor car I guess but we bought it new and kept it because it is a fun convertible to drive around. After the fault code happened I changed out the front O2 sensor. After 4 or 5 cycles the CEL went off. It stayed off for 2 days. I thought I had found the issue but now it is back on. The engine is running great and idles great. I did a quick check for any obvious vaccum leaks but didn't find one, and also because it idles so well I am thinking the lean condition is something else. My recent thought is to pull out the MAF and to spray clean the sensor with sensor cleaner. I can't think of anything else that would trigger a lean code on an engine with relatively low miles. I will change out a couple of vaccum hoses because visually at least they look in poor condition. Touch them and you end up with black all over your hands. Hey the car is 15 years old. Being a Saab turbo I wasn't sure if I missed anything else to consider to get rid of the code.
 
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Old 08-27-14, 04:15 AM
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First thing I thought of was fuel pressure, so get a gauge on it and see what the pump is producing. Here's some additional items:

- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection

Pretty good article here, too:

https://repairpal.com/OBD-II-Code-P0171-and-P0174
 
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Old 08-27-14, 08:14 PM
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Thanks Tow_Guy. I checked out the link you sent and it did have alot of good information. Fuel pressure was the last thing I would have thought only because the engine starts and runs and idles so well. I am guessing you have seen many with issue behind your truck. I did pour a can of injector cleaner into it yesterday so I will see what that will do. It won't hurt regardless of whether the injectors are the issue. I also always thought that bad fuel pumps went basically bad as in on and off and that they would not drop a very minor level of pressure without driving performance failure. I will check the pressure however, and change out the fuel and air filter along with cleaning the MAP sensor as a next step. The MAP has never been cleaned and though there is only 50K on the car, 15 years of airflow could easily have left it's mark. I have never dealt with a lean code before so hope I can find what needs to be done sooner and not later.
 
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Old 09-03-14, 11:58 AM
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Update

Just to update, I put a pint of Seafoam in the tank, replaced a couple of vaccum hoses that were deteriorated from age, and replaced the fuel filter. I checked the pump fuel pressure and it is where it should be. When I changed the filter I disconnected the battery for safety and this cancelled out the CEL. So far it has not come back on, so I am thinking that it may have been a dirty fuel injector issue that the Seafoam addressed, or a partially clogged filter, or both, but as I know of it, the P0171 code only comes on based on a long term mixture condition, so time will tell I guess. The car idles and runs as it should including when the turbo kicks on and it did before the fault code showed up so whatever the issue it must not be anything major I guess.
 
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Old 10-07-14, 05:40 PM
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It has now been over 2 weeks since I cleared the lean code, and cleaned the MAF, replaced the fuel filter, air filter, changed out a vaccum line, and put Seafoam in the tank. Prior to this I had replaced the 02 sensor but that had only cleared the code for a couple of days. So far the CEL is staying off now. Does anyone know how long it could take for the code to come back if the problem was not corrected considering that the P0171 lean code is a code that is activated over what has been described as a 'long term' lean condition. How many warm up cycles is considered a 'long term'? I am hoping that one or more of the actions I have taken has solved the issue permanently.
 
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Old 10-08-14, 04:03 AM
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Not more than a couple of days, I would think. In a lot of instances stuff that's NOT fixed lights the light up the very next cycle.
 
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Old 10-08-14, 07:17 PM
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Thanks, Vic. If this is the case then I nailed it. At this point I am guessing it was a dirty MAF sensor as the primary reason for the code as the car ran well with the light on the same as it would have run with a simple gas cap evap code.
 
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