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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 18692
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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Sentra: I have a 04 Nissan 1.8l. Short term is at 25% long

Customer Question

I have a 04 Nissan 1.8l. Short term is at 25% long term is at 9%. O2v at .23. This is in idle and in open loop at 190 degrees. In idle the stft sometimes fluctuates to 0. This causes idle to drop. However it stays that way for a few seconds then goes back to 25. I do also notice at 2000 rpms my stft also drops but my O2 voltage does go higher only when I release throttle. When it returns to idle everything goes back to original readings. Any thoughts on what's causing high stft and being in open loop?
Submitted: 1 year ago.
Category: Nissan
Expert:  Jay replied 1 year ago.
Hi, My name is*****'m happy to help you. During our conversation, I may be presenting you with different things to try, and ask you some Questions to get a better understand of the issue so I can answer your question properly. So stick with me to the end, and I am sure we should be able to get this issue resolved for you! This is most of the time caused by dirt on the MAF sensor, or if the MAF fallen out of spec and is not metering air properly. I would recommend you get a can of CRC MAF sensor cleaner and remove and clean the MAF sensor and see if that helps. The 25% is a lean condition. If you have a cold air intake or K&N air filter that can cause damage to the maf sensor. If you can unplug you should see the fuel trim readings drop to -25% If it does, then you have no air leaks, you have a bad MAF sensor. It will want to auto correct which is when it will drop to Zero. Once it auto corrects, it then works off the sensor readings and that is when the fuel trim climbs again. If you do need a MAF sensor. Do not get one from your local auto parts store. They never work right. If you do get one from a auto parts store they never meter the fuel trim right, and if you do get one that meters the fuel trim properly it will flat line the front 02 sensor and start causing all sorts of other codes which will have you really chasing your tail. So when it comes to electrical parts, stick with the dealer. If you have any more questions on this, please feel free to ask.If not, and you're satisfied with my help, please Rate me. I hope I have provided you with Excellent Service.Thanks Jay!
Customer: replied 1 year ago.
Will this bring trims to normal? Would bad maf keep it in open loop? I do not have a cold air intake. I will check to see when I unplug maf if this drops trim.
Expert:  Jay replied 1 year ago.
Bad MAF could make it loop depending on how bad it is. Did you unplug it and start the car and see if the readings dropped to -25%?
Customer: replied 1 year ago.
Yes unplugged maf fuel trim dropped to -25%. What would be my next step. I know you said it's a bad maf however they cost about $200 @ the dealer for oem. I just want to be sure that the problem
Expert:  Jay replied 1 year ago.
You just verified it. If the fuel trim can drop to the default -25% that means you have no air leaks. If you did it would drop to -18% or something cause of the air leak it can't drop to -25% So you verified it if it drops to -25% If you have any more questions on this, please feel free to ask. If not, and you're satisfied with my help, please Rate me. I hope I have provided you with Excellent Service. Thanks Jay!
Customer: replied 1 year ago.
Ok will change maf sensor. Will that solve rough idle and hard starting also?
Expert:  Jay replied 1 year ago.
You never mentioned a hard start issue. That maybe something totally different and may require a new question as we are limited to one topic per question. Let me guess, it's only hard to start after the car has been sitting for a fairly long period of time after it has been driven. Once you start it, it runs ruff for a little but eventually clears up and runs better as it warms up? Is that correct?
Customer: replied 1 year ago.
Well I do notice a rough idle at higher rpms it seems to run fine. Goes into closed loop and have no problems accelerating. However in idle there is a vibration in gear D or R. It's not as bad in park or neutral.could this be a fuel problem
Expert:  Jay replied 1 year ago.
Maybe... Hard to tell exactly. But I would certainly correct the fuel trim issue first, then move on to this issue. The fuel trim could certainly affect how it runs. If you have any more questions on this, please feel free to ask. If not, and you're satisfied with my help, please Rate me. I hope I have provided you with Excellent Service. Thanks Jay!
Customer: replied 1 year ago.
Right now pricing maf sensor will leave rating/ feedback when parts is replaced pending outcome. Not sure if it will fix the problem however I have no problems with service I received.
Expert:  Jay replied 1 year ago.
ok.. Let me know how you make out
Customer: replied 1 year ago.
Replaced mass airflow sensor. Idle seems a little better. Here is my fuel trims now. Lt 0 st 17 at idle. O2 v .305. Did the ecm relearn and idle relearn. Fuel trims still don't seem right any ideas?
Expert:  Jay replied 1 year ago.
What is the Short Term fuel trim at idle after it's all warmed up?
Expert:  Jay replied 1 year ago.
You don't have a K&N air filter do you?
Customer: replied 1 year ago.
No stock air filter short term ft fluctuates 18 -20 long term fuel trim is 0
Expert:  Jay replied 1 year ago.
That is still lean. Did you get gas recently? I have seen bad gas do this as well. Let me know..
Customer: replied 1 year ago.
Well I do put 92 grade gas and my other vehicle seems to run fine on that gas
Expert:  Jay replied 1 year ago.
How long ago did you get gas? does it still have the same tank of gas from when you asked this question back on the 11th? What state are you in?
Customer: replied 1 year ago.
I live in Hawaii and no this is a different tank of gas from first problem. I really don't believe it's the fuel. I have another vehicle that has the same fuel with no problems. I don't know why short term fuel trim is so high while long term is at 0 any ideas
Expert:  Jay replied 1 year ago.
long term does not read live. Short term does. Long term is a over all reading after a certain period of time. This could be a bad 02 sensor maybe causing this. Does it run better with the new MAF sensor?
Customer: replied 1 year ago.
A little better
Expert:  Jay replied 1 year ago.
Have you driven it since putting it in? How far did you drive?
Customer: replied 1 year ago.
I did also change cam sensor car seems to start up alot quicker also . Idle still a bit rough but better. Will change crank sensor when I have more time.
Customer: replied 1 year ago.
Didn't drive it just let it idle and put it in gear D and r while stepping g brake.
Expert:  Jay replied 1 year ago.
You need to drive the car.. it will learn as you drive. You always need to take cars for at least a 5 to 10 mile test drive. Did you change the Cam Sensor with one from the dealer?
Customer: replied 1 year ago.
O2 sensor. I do notice o2 voltage stays at .305 and doesn't fluctuate rich lean is that normal for sentras
Expert:  Jay replied 1 year ago.
Take the car for a good test drive.. like 5 to 10 miles. Then recheck your readings at idle.
Customer: replied 1 year ago.
Ok will do let you know how it goes
Expert:  Jay replied 1 year ago.
ok