my Infiniti is currently at about 205K and I developed a leak in the front Y-Pipe that I had a shop replace with a Walker Y-pipe to save on the part as I only plan to have the car for another year maybe two at most before going the EV route.
After about 100 miles of driving after replacing the pipe, I got a service engine light with the code P2A00. I need some assistance reading the live data before I take it back to the shop and spend on additional diagnostics.
what are the reference voltages for my car? That info is a bit elusive.
my current live data shows:
B1S1 at about 1.9 - 2.1 volts (if I speed up and let go of the gas pedal it goes to 5.1v)
B2S1 at about 1.9 - 2.1 volts (if I speed up and let go of the gas pedal it goes to 5.1v)
B1S2 is moving between 0.3 - 0.8 (this seems correct from what I was reading)
B2S2 is moving between 0.3 - 0.8 (this seems correct from what I was reading)
Could this be related to that Y-pipe or potential MTBF for the exhaust components? Think of getting an OEM pipe from a salvage yard and replacing them again. (In retrospect probably should have done it in the first place)
2008 G35x AWD Infiniti
Could this be related to that Y-pipe
could be, if it's leaking.
Lambda sensors can have anywhere from 0 to 5 V.
There's some basic troubleshooting here: https://www.obd-codes.com/p2a00
but in this case you need a live graph to understand what's going on.
You still want an EV knowing all the problems they have?
Thanks when I have some time tomorrow after work will try to take a look at the live graphs now that I understand a bit better what I'm looking for.
this will be a bit of a long story apologize but if I shorten it will lose context:
Regarding EVs from my first personal trial experience renting the Model Y on an about 2.5k Trip a few months back from Chicago to Montreal Canada, it was one of the best car experiences I've ever had. After getting used to the instant torque of the EV and one-pedal driving my G35 now feels so lethargic and unrefined in my new outlook comparison. The autopilot feature worked flawlessly for the majority of the trip which made the cruise quite enjoyable, but I did turn it off when I was going through the construction area just for an extra safety precaution. I know other than the tesla charging network still has a long way to go on reliability and seamless operation, but the tesla superchargers were flawless with auto redirect if the charging stations filled up while I was going to one adding little to no additional time. I was also able to save quite a bit on fuel costs. when I mapped out my trip with a comparable gas SUV at the time gas was going to cost me a little over $800. With the Tesla supercharger network and hotel complementary L2 charging where I was able to find it, I only spent $180 for electricity. Note: the EV rental only was about $70 more than the Gas SUV with Hertz at the time.
from indirect experience, I have 3 coworkers with a 2015 model S 90D, a 2018 Model 3 Long Range, and a 2020 Model 3 Long Range. Those cars are now at over 160K, 90K, and about 50K. Outside of a few cosmetic issues that had been fixed when they first received their cars under warranty, they had no other issues with electronics, batteries, or motors in the midwest region. Note: the model S at 150K has some suspension parts replaced as part of regular wear but that's to be expected in my view regardless of EV or ICE car. the Model S when he got it new got on average 260-240mi. now gets between 220-240mi depending on how he drives so about 20 miles less in about 7 years which to me is respectable. Both model 3s when they got them new averaged about 320mi and from what they told me 2020 model 3 shows no noticeable drop in milage after about 50K. The 2018 90K model 3 has a slight average loss from new of about 5mi from what my friend said at 90K when he takes longer trips.
regarding electricity cost of ownership compared to gas, the saving is astronomical if you do it right. all three of my coworkers have 40A L2 chargers that cost them $500 to install and they set their electric billing to hourly pricing. They set their cars to always start charging between 1:00 AM and 5:00 AM in their area that's the cheapest hourly pricing for them and on average two days out of the week the price even goes down close to 0 per Kw and even negative albeit for a few min on the negative number :-). On average they drive about 17K-25K a year almost exclusively charging at home with the exceptions of long trips. when they checked their hourly statistics each year during the night their cars on average cost them $140 - $220 to keep charged through the whole year. To me that's amazing I go through 160-300 for fuel per month and their cars leave mine in the dust.
now I do need to point out that my coworkers might not be the average consumer that drives a car and only might do maintenance if something breaks. they did their research and as with any vehicle if you want longevity proper maintenance is key:
* switching to hourly pricing and timing their charging when electricity is cheap during the night saved them a lot of $$$ offsetting extra car costs in no time.
* They usually don't drive below 20% and don't charge above 80% except for long trips which they do maybe once or twice a year to help with battery life.
* Cars are usually in the garage and not exposed to severe cold in winter for too long.
* Change the active battery cooling coolant at intervals of about 4 years per their dealer's instruction.
I'm also getting solar panels next year which will further help to offset car charging. based on the above for me an EV makes sense for my use case.
On your 2008 G35 the A/F sensor voltage @ 14.7:1 air:fuel ratio is 2.2 volts.
When you forced a lean condition by speeding up and releasing the accelerator pedal the voltage readings on both of your A/F sensors respond correctly by spiking up to 5 volts, so the sensors are working right.
On yours the P2A00 dtc is set when the A/F sensor voltage is shifted to the lean side for too long.
But your Live Data doesn't show that happening. Maybe look at the Freeze Frame data from when that P2A00 was set to see what both of the B1S1 and B2S1 A/F voltages were. You're likely chasing down either an intake vacuum leak or an exhaust leak so look at stuff like Fuel Trims, ECT temp, MAF g/s, RPMs, for a clue.
Less likely an intermittent fuel pressure issue or a lazy fuel injector on bank 1.
That's why it will be useful to see what the B2S1 voltage was too in the Freeze Frame data. Was it maybe shifted lean but not quite lean enough to set a code? Or not?
Thank you for the graph and explanation that helps a lot. I'll take a look at the freeze frames after work today. but from what you mentioned sounds like my sensors might be fine. maybe the new front Y pipe and flanges don't quite create a good seal. That's what I get for trying to go cheap. The first time I place something other than OE thinking it was just a metal pipe and I get an issue 🙁
@jack62 below is the print out of the freeze frame as well as live data graphs at idle
enView Freeze Frame
Number of DTCs stored in this ECU 1
DTC that caused required freeze frame data storageP2A00
Fuel system 1 statusCL
Calculated Load Value(%)27.5
Engine Coolant Temperature(¡£C)95
Short Term Fuel Trim -Bank 1(%)4.7
Long Term Fuel Trim - Bank 1(%)9.4
Short Term Fuel Trim -Bank 2(%)-6.3
Long Term Fuel Trim - Bank 2(%)9.4
Engine RPM(rpm) 625
Vehicle Speed Sensor(km/h)0
Ignition Timing Advance for #1 Cylinder(¡£)15.0
Intake Air Temperature(¡£C)15
Air Flow Rate from Mass Air Flow Sensor(g/s)4.86
Absolute Throttle Position(%)2.0
Oxygen Sensor Output Voltage Bank 1-Sensor 2(V)0.100
Short Term Fuel Trim Bank 1-Sensor 2(%)99.2
Oxygen Sensor Output Voltage Bank 2-Sensor 2(V)0.830
Short Term Fuel Trim Bank 2-Sensor 2(%)99.2
Time Since Engine Start(sec)1006
Distance Travelled While MIL is Activated(Km)0
Equivalence Ratio (lambda)(Bank 1-Sensor 1)1.004
Oxygen Sensor Voltage (Bank 1-Sensor 1)(V)1.990
Equivalence Ratio (lambda)(Bank 2-Sensor 1)0.993
Oxygen Sensor Voltage (Bank 2-Sensor 1)(V)2.135
Commanded Evaporative Purge(%)0.0
Fuel Level Input(%)87.1
Number of warm-ups since diagnostic trouble codes cleared3
Distance since diagnostic trouble codes cleared(Km)142
Evap System Vapor Pressure(Pa)0.00
Barometric Pressure(kPa)99
Catalyst Temperature Bank 1,Sensor 1(¡£C)416.0
Catalyst Temperature Bank 2,Sensor 1(¡£C)416.0
Control module voltage(V)12.960
Absolute Load Value(%)19.6
Commanded Equivalence Ratio0.979
Relative Throttle Position(%)0.8
Absolute Throttle Position B(%)2.0
Accelerator Pedal Position D(%)0.0
Accelerator Pedal Position E(%)0.0
Commanded Throttle Actuator Control(%)2.0
Time run by the engine while MIL activated0 hrs,0 min
Engine Run Time since diagnostic trouble codes cleared3 hrs,53 min
A few things catch my attention in the P2A00 Freeze Frame
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When the code was set the engine had been running for 16 minutes so it was warmed up
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The MAF was reporting airflow of 4.86 g/s @ 625 rpm (idle). On your 3.5L engine you'd expect that to be around 3.5 g/s so 4.86 g/s is a little high
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The combined STFT +4.7 and LTFT +9.4 ((fuel trims)) on bank 1 are +14.1%. (confirms the lean condition on bank 1 when the code was set).
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The combined STFT -6.3 and LTFT +9.4 ((fuel trims)) on bank 2 are +3.1%. (at 16 minutes running time the STFT is pulling down the bank 2 fuel trims to a reasonable +3.1%) ((intake manifold or exhaust manifold or exhaust leak? As an engine heats up and parts expand leaks tend to become smaller)
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Maybe the most interesting thing in the Freeze Frame is that the bank 1 sensor 2 voltage is pegged lean at 0.1 Volts (too much O2)
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That makes me suspect an exhaust leak so I did a little research on your G35 Infiniti because I wanted to see how close that Y pipe you had replaced was to the cats. I stumbled across some common issues with its exhaust system which are causes for setting the P2A00 or P2A03 codes
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One common place is where the cats are connected to the cross hanger which supports them
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There's a hanger bracket welded to the cats to allow it to be bolted to the cross hanger
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((close up pic))
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They seem to be prone to developing cracks in the cat around the weld area and notice it's right next to the downstream O2 sensor location
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The easiest thing to do may be to have both the intake and the exhaust smoke tested for leaks
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Also, when you determine the cause and make the repair you have to clear the Mixture Ratio Self Learning Control. Here's the drill for that:
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((click to enlarge))
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live idle graphs:
I will give you my non expert interpretation
O2S11 graph (I assume upstream bank 1):
the up and down fluctuations are good. Sensor is working.
value seems to hover around 2.0V
If you look at Jack's graph, that corresponds to a ratio of about 14:1
That's less than 14.7 indicating a rich mixture. (not enough air).
Fuel trim is strongly positive indicating computer is trying to add fuel.
O2S21 (upstream bank 2?):
Looks high indicating lean mixture. Fuel trim again positive so computer is trying to compensate, which seems to agree. If there is an exhaust leak on this bank, then the mixture will always look lean despite the computer trying to compensate.
downstream sensors (O2S12 & O2S22 I assume given they look like narrowband values):
fluctuating wildly. It is my understanding that values should not fluctuate so much, because the catalytic converter uses up oxygen in the catalytic reactions. Either the catalytic converter is worn out (which can happen from running rich too long), or an exhaust leak is throwing it off.
I know this isn't an answer, but maybe it'll add something to your understanding, and hopefully bring you closer to the solution.
Thank you for the analysis hopefully my catalytic converters weren't damaged by the rich mixture. I had the Y-pipe and flanges replaced about a week ago and haven't driven too much. but I noticed the running rich my average gas mileage dropped from 21mpg to about 17mpg.
I'll try to see if I can find any leaks otherwise I'll probably bring the car back to the shop after the New Year.
Thank you again happy new year
Got the diagnosis on my car looks like my catalytic converters are shot they have multiple microfractures around the welds letting air in and need new ones. I wasn't able to find salvage ones. I don't want to spend an arm and a leg on Infiniti OE parts do you know if the below parts would be decent to last a year or two?
considering one of the three brands below:
Catalytic Converter Davico Mfg 17115
Catalytic Converter Davico Mfg 17116
Evan Fischer
Part Number: REPI960312
DIY Solutions Catalytic Converter Set
Part Number: 29132-02998286
I'll also replace the O2s with the OE NTK sensors since these sensors have 205K+ to avoid damaging the new catalytic converters
Why not take it to a muffler shop and get the cracks properly welded up?
It was a shop that gave me the recommendation. They said there were leaks coming from welds on the external side of the welded shields as well as under the shields which would require cutting them off and checking which parts rusted away and if it's possible to fix them. They recommended replacement based on labor hours and were not able to guarantee that they can fix these.