2000 Infiniti I30 Failed emissions test Code po171
2000 Infiniti I30 Failed emissions test Code po171
Car runs rough just at cold start up. Had bank 1 o2 sensor replaced. FAM cleaned and all igntion coils replaced last year. Vacum leak, fuel system problem? Where do I turn next? Any idea on repair costs?
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Q45tech
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Re: 2000 Infiniti I30 Failed emissions test Code po171 (jcchait)
Start with new spark plugs and BG44k or a couple of Techrons in 1/2 tank of gasoline.
Could be the E10 [inherent leanness] with one or more other problems try a full tank of non E10 gasoline.
Could be the E10 [inherent leanness] with one or more other problems try a full tank of non E10 gasoline.
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mplomondon311
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Re: 2000 Infiniti I30 Failed emissions test Code po171 (jcchait)
I had the same issue yesterday. Now this isn't what anyone wants to hear, but the code read P0171 which came back as a Mass Airflow Sensor. This part for the 2000 I30 I had priced around $458.00 and then the Electronic Control Module has to be reprogrammed by the dealer for $130.00. Pain in the wallet but an easy fix. You can see the MAF sensor right on top of your intake tube with a wire harness sticking out of the top at a 90 degree angle. Good luck all!
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SteveTheTech
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Re: 2000 Infiniti I30 Failed emissions test Code po171 (jcchait)
Hey guys Welcome to NICO
I agree with the Mikes assessment of this situation.A MAF will cause all kinds of driveability issues, from a lean miss to dying on acceleration and possibly a rough idle depending on the output voltage signal. I would say have it looked at unless you have access to a scanner or have a multimeter and alot of free time. You can just start throwing parts at the car but that is not the right way to fix a car and it makes it difficult to make an accurate diagnosis later down the line.
If you need any advice or a second opinion on something there are tons of people here that can help.
I agree with the Mikes assessment of this situation.A MAF will cause all kinds of driveability issues, from a lean miss to dying on acceleration and possibly a rough idle depending on the output voltage signal. I would say have it looked at unless you have access to a scanner or have a multimeter and alot of free time. You can just start throwing parts at the car but that is not the right way to fix a car and it makes it difficult to make an accurate diagnosis later down the line.
If you need any advice or a second opinion on something there are tons of people here that can help.
Re: 2000 Infiniti I30 Failed emissions test Code po171 (jcchait)
IF YOU HAVE A PLASTIC INTAKE PLENUM, THE GASKET IS PROBABLY BROKEN IN SEVERAL PIECES. IF YOU HAVE AN ALUMINUM INTAKE PLENUM THAN PROBABLY RULE THAT OUT. i HAVE HAD A LOT OF INTAKE PLENUM GASKETS CAUSE ONLY COLD DRIVEABILITY AND RUNS FINE WARMED UP. SPRAY BRAKEKLEEN AROUND PLENUM WHEN IDLING AND SEE IF IDLE CHANGES.
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Unnatural1
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Re: 2000 Infiniti I30 Failed emissions test Code po171 (jcchait)
P0171 - Bank 1 - Fuel system lean
Without a scan tool diagnosis is tough. Basically, the bank 1 O2 sensor is reading an excessive amount of oxygen in the exhaust and in turn the PCM is trying to add fuel to the mixture to bring it back to stoichiometric. When the PCM can no longer bring the mixture back into check it sets a code.
An MAF sensor is only one of MANY possibilities. Please don't run out and buy an MAF sensor with out having some testing done. The most common cause of this DTC, that I see, is vacuum leaks. Other causes are: a dirty fuel filter, bad fuel pump, bad injectors, misfires (spark plugs, coils, etc...) and the list goes on.
Since the P0171 code is the only code set currently, we can assume the problem is something that will only affect bank 1. That generally rules out many causes, such as most of the fuel system related causes except for maybe a bad injector.
As mentioned previously, I find vacuum leaks are the most common cause of this code. Leaks are easy to check for especially if you have a scan tool that can read OBD II Generic datastream info and a can of carb/intake cleaner. But first try cleaning the MAF sensor with a can of MAF sensor cleaner or electrical cleaner; found at most auto part stores.
Next, simply inspect the top of the engine for loose, missing, or otherwise damaged vacuum hoses. Also check for cracks in the intake tube between the MAF sensor and the throttle body. Listen for a hissing noise as the engine is running while inspecting under the hood. If you hear a LOUD hissing noise you can usually trace down the vacuum leak.
Beyond these checks, you need specialized equipment to continue diagnosis typically. If you happen to have access to a generic OBD II code reader that can read the PCM datastream you can monitor the "Bank 1 HO2S" while spray a can of carb/intake cleaner around the intake manifold and vacuum lines. Watch for the O2 sensors readings to spike to nearly 1.00 volts. Continue spraying that area to confirm the voltage continues to stay around 1.00 volts. Simply listening for changes in idle usually doesn't work because generally it won't change that much due to the PCM's previously mentioned adaptive fuel strategy.
These codes can be hard to trace down sometimes due to the number of possible causes. But if you have or have access to a scan tool and the knowledge to use it you can try the above.
Modified by Unnatural1 at 9:07 PM 10/12/2008
Without a scan tool diagnosis is tough. Basically, the bank 1 O2 sensor is reading an excessive amount of oxygen in the exhaust and in turn the PCM is trying to add fuel to the mixture to bring it back to stoichiometric. When the PCM can no longer bring the mixture back into check it sets a code.
An MAF sensor is only one of MANY possibilities. Please don't run out and buy an MAF sensor with out having some testing done. The most common cause of this DTC, that I see, is vacuum leaks. Other causes are: a dirty fuel filter, bad fuel pump, bad injectors, misfires (spark plugs, coils, etc...) and the list goes on.
Since the P0171 code is the only code set currently, we can assume the problem is something that will only affect bank 1. That generally rules out many causes, such as most of the fuel system related causes except for maybe a bad injector.
As mentioned previously, I find vacuum leaks are the most common cause of this code. Leaks are easy to check for especially if you have a scan tool that can read OBD II Generic datastream info and a can of carb/intake cleaner. But first try cleaning the MAF sensor with a can of MAF sensor cleaner or electrical cleaner; found at most auto part stores.
Next, simply inspect the top of the engine for loose, missing, or otherwise damaged vacuum hoses. Also check for cracks in the intake tube between the MAF sensor and the throttle body. Listen for a hissing noise as the engine is running while inspecting under the hood. If you hear a LOUD hissing noise you can usually trace down the vacuum leak.
Beyond these checks, you need specialized equipment to continue diagnosis typically. If you happen to have access to a generic OBD II code reader that can read the PCM datastream you can monitor the "Bank 1 HO2S" while spray a can of carb/intake cleaner around the intake manifold and vacuum lines. Watch for the O2 sensors readings to spike to nearly 1.00 volts. Continue spraying that area to confirm the voltage continues to stay around 1.00 volts. Simply listening for changes in idle usually doesn't work because generally it won't change that much due to the PCM's previously mentioned adaptive fuel strategy.
These codes can be hard to trace down sometimes due to the number of possible causes. But if you have or have access to a scan tool and the knowledge to use it you can try the above.
Modified by Unnatural1 at 9:07 PM 10/12/2008
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mplomondon311
- Posts: 8
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- Car: 2000 Infiniti I30
Re: 2000 Infiniti I30 Failed emissions test Code po171 (Unnatural1)
Just to put in my situation on this. I have had the MAF replaced at far cheaper than I was told it would be. Also, I replaced the air filter (advised by the gurus at Infiniti) and sure enough the filter was naaasty! After this quick fix it was amusing to see how much power gain and driveability the car has gained since the replacement. Just as Unnatural1 said, DON'T JUST GO OUT AND PICK UP THE SENSOR! Ask a professional first, as it can be any array of sensors or leaks! Again good luck!