#1
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Idle air volume learning problem
Attempted the above procedure step by step according to the factory service manual.
Start engine and warm it up to normal operating temperature. 4. Turn ignition switch OFF and wait at least 10 seconds. 5. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds. 6. Repeat the following procedure quickly five times within 5 seconds. - Fully depress the accelerator pedal. - Fully release the accelerator pedal. 7. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops blinking and turned ON. 8. Fully release the accelerator pedal within 3 seconds after the MIL turned ON. 9. Start engine and let it idle. 10. Wait 20 seconds. #1. At step #7, the MIL never blinks. It is always a steady on no matter how long I fully depress the pedal. Could it be a bad throttle position sensor or accelerator pedal position sensor? #2. The engine hesitates sometimes from low speed (10-20 mph) and low rpm (1000 - 1100 rpm) acceleration after warming up. Dirty fuel injectors? There are no DTC's pending or otherwise. Any thoughts or suggestions would be appreciated. 2011 Altima 2.5s 75000 miles. |
#2
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Why are you performing the Idle air volume learning procedure?
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#3
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I removed the throttle body and cleaned it with throttle body cleaner. The side which connects to the intake plenum was a mess with dried oil. I got it looking new again.
A Nissan mechanic advised me to do the idle air volume learning procedure afterwords even though the manual says otherwise. |
#4
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I did the easy stuff pulled the plugs they look good. Checked for vacuum leaks no problem there. Idle is very smooth and quite.
700 RPM |
#5
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trust me when I tell you it can take several attempts.
When I made the mistake of cleaning the TB on my 2005 (with only a rag) It messed it all up and would not idle. I had to perform the procedure. Took me like a half hour to finally get the light to do its thing and the procedure to be successful. Pay very close attention as you follow the procedure |
#6
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Engine hesitation
Thx for your input Soap, but right now more concerned with the engine hesitation as it is gradually getting worse. Any load on engine causes hesitation now e.g. sitting at red light in drive, foot on brake and air conditioner running.
Still no DTC's but my latest scan shows some misfires on cylinder #1 when observing mode 6. Should I look at the fuel injector first or the coil or something else? It is not a desperate situation but would love to here other opinions and suggestions. Don't be shy. Jack |
#7
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coil.
had multiple coil issues with my Altima, Until that is I replaced the ground wire that goes to the passenger side of the engine, right by the oil cap actually. That is the ground for the coils. Once I did that Misfire problems were gone. Before that it seemed to eat coils. If you can help it I would replace all 4. NGK plugs also. |
#8
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grounds are good
scanned. Mode 6 says I have a missfire on #1 cylinder. I swapped #1 and #3 coil packs. Drove the car for 25 minutes. scanned again ..... still misfire on #1 cylinder. Put in new NGK spark plugs ... no difference. Put in different MAF sensor, No difference. Cleaned out throttle body ... no help. Checked for air leaks in intake system.
Drove the car to Chicago from Philadelphia and back doing 70 - 80 miles per hour and no problems at steady speeds. Only hesitates under load. Fuel pressure must be ok. I scanned and graphed the accelerator pedal position sensor and the throttle position sensor. Both seem to be working ok but not ruling them out. Last but not least is the fuel injectors .... no way to test them. Misfires are getting worst but still no MIL Any wizards out there with any suggestions? |
#9
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Check the main ground wire from the battery to the transmission case. It is very common for it to corrode off at the transmission. The wire goes from the negative post on the battery to the inner fender area under the battery tray and then to the transmission case. Grab the wire at the transmission side and pull on it to make sure it is connected.
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#10
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did you check your grounds?
Grounds are very important. The main ground is from the battery to the transmission, meets the fenderwell in the middle, Also the grounds by the oil cap. |
#11
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grounds
if the ground from the battery to the transmission case was bad, would not there be more problems with the car then just a misfire?
Just asking ... Recently I got a P0300 random misfire. Misfires on # 1, 2, and 3. Then the next day a P0302 code. Checked my scan tool and showed multiple misfires on cylinder #2 and no codes for 2 and 3. Still clean on #4. Swapped # 4 and # 2 coil packs. Now the misfires are on #4 cylinder. Thought I had it figured out ... nope. Put a new coil pack on #4 and no help. Now missfiring on #4 with the new coil pack. The mystery continues. Have not rulled out many things : bad gasoline, bad throttle body, corroded electrical connections, disfunctional PCM, bad Intake air temperature sensor. All brand new NGK spark plugs. New air cleaner. Throttle body has been cleaned. STFT and LTFT are + or - 2 3 % . Well within good a/f mixture tolerance. No sign of too lean or rich mixture. Lambda = .9 to 1.1 on average. More updates later Jack |
#12
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you may have a faulty PCM.
Ohm your wires from the coil to the pcm. If all pass then you may have a bad one. IIRC coil problems could take out the drivers in the PCM. thus why It is not resolving the problem. As for the grounds, not necessarily. I have seen many cars act in different ways with bad grounds. |
#13
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update
took the car to the local mechanic .... they gave up after 3 hours and told me to take it to Nissan .....
Take it to a dealership eeeeeeek !! |
#14
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computer
looks like the worst is going to happen ,,,, PCM might be bad
going to cost big bucks :(( |
#15
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Hopefully not so bad,
as I stated before it is possible. Not sure if the drivers can be repaired but I have not heard of it. Just replacement and reprogramming Best of luck to you |
Tags |
air, idle, learning, problem, volume |
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