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Topic
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:stick: Hello, My STAY DIRTY FRIENDS:
I have an 04 NISSAN ALTIMA 2.5L engine that is stalling intermittently. I found the battery cables loose and tighten them, the oil was just change, i’m not sure when the last time it was tuned up. It’s starts up fine,so it is not a no-start, but after my niece a has driven the car for a while she says that car would just stall. I turned the car on at my home and snap throttled the car with the gas pedal and it stalled on me, but I started it again and gunned it a couple of times again and it didn’t stalled. These intermittent issues are the mother of all evils. Also, trans fluid ok, and the car from my point has a slight shake,but not a terrible one. Please give me some feedback so maybe I can remedy this problem for her. I took the liberty of putting my scanner on the car and got a PO420 code that has been there for awhile, but I went to pending codes and got a 171 system too lean Bank 1.
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Replies
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Causes
A code P0420 may mean that one or more of the following has happened:
Leaded fuel was used where unleaded was called for
A damaged or failed oxygen sensor (HO2S)
Downstream oxygen sensor (HO2S) wiring damaged or connected improperly
The engine coolant temperature sensor is not working properly
Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe
Retarded spark timing
The oxygen sensors in front and behind the converter are reporting too similar of readings Leaking fuel injector or high fuel pressure
Cylinder misfire
Oil contamination
Possible Solutions
Some suggested steps for troubleshooting a P0420 error code include: Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required. Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady). Inspect the downstream heated oxygen sensor (HO2S), replace if necessary Replace the catalytic converter
Overall probably the biggest mistake vehicles owners make when they have a P0420 code is to simply replace an oxygen sensor (H02S). It is important to do proper diagnosis so you’re not wasting money replacing parts unnecessarily.Read more at: http://www.obd-codes.com/p0420
Lean bank 1 is clogged injectors
Collegeman or Eric this one is for you two dwell upon. She begins to drive the car then all of sudden the car get a hesitation then stalls,but if turn off the ignition and start it again, it will run again until she acts up again with the symptoms I mentioned before. banana:
Bank 1 lean code, DOES NOT mean clogged injectors. A lean code is to much air or not enough fuel. Make sure your fuel pressure is good and look for a vacuum leak. If you don’t find one then and only then can you start to assume fuel injectors, or an exhaust leak. Does this happen when the car is hot? cold? or all temps?
Good question? My niece told me today for instance; the car started fine in the morning at 9am,so the crank no start was ruled out. They ran errands for about 2 hrs then returned home. It was not until 1pm that she started the car and got a short distance then the car hestitated then stalled out. I’m was dwelling on a hot engine, but it did have time to cool when they returned; that is why I feel intermittens are the mother of ailments. I put the scanner on the car because if she stalled it would set a DTC, but the PO420 code has been there for awhile. The PO171 was pending and probably in a another drive cycle it will set a code. I was thinking a vacuum leak or MAF as possibilities.
If you’re leaning towards a hot engine. Ask her if it stalls out when hot, and if it does, does it start right back up or does it only start back up once cooled down. If it stalls only when hot, and crank no starts right afterwords, and then starts after the car has been sitting, we need to suspect a Crank Position Sensor. If this is the case i’ll go on to explain how we can diagnose this later on. Let’s see what information we can get out of her first. Also yes your right, what your dealing with is called drive-ability diagnosis which is one of the hardest situation to be in, because it can be so many different things, and you have no direction to point in. Get as much information from her as you can, keep us posted.
P.S. Tap on the MAF with the butt of a screw driver, and see if it tries to stall.
Today when she arrived at my so I could put my scanner was about a 25 minute drive for her. I pulled the codes mentioned, but that was when I stepped on the gas (snap throttle simulation)and it stalled out on me. It started right away and stayed running up until she got home about 7pm and no stall. Crank sensor was a thought of especially in this Florida heat then the stalling should get progressively worse. I will put together a more detailed symptom list by tomorrow. I need to get some rest. Thanks for all the help.
Stay dirty, stay well
greasemanThe p0171 can be a few things. fuel pressure, MAF (try cleaning it with MAF cleaner)
vacuum leaks. Does your scanner read live data? would like to see what fuel trims are
doing. These cars also had cam and crank sensor problems. If you have a fuel pressure
gauge to read fuel pressure that would eliminate fuel. Should be 52 psi.For now I agree that ignoring the P0420 is OK. I think focusing on the lean code is a good place to start for the stalling/performance issue. Nissans have also been known to have injector problems as well as intake manifold gasket leaks. Crank sensors are also known issues but they usually set codes. You might start with the basics which I cover here.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
Try that to start with and keep us posted on what you find.
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