New car new problem! (Reposted)

[avguy]

Battery testing tools are normally capable of showing if a battery is good or bad. However, as I already said above, there are some uncommon situations where a cell is bad, and the tool can't pick that up. I would lean in that direction when the battery is losing static voltage, and load testing shows bad voltage recovery numbers, as your Aveo is doing.

Doing another battery load test is definitely a good idea. And if the results are the same as the first test, that would reinforce the theory that something is wrong with the charging system. I'm saying that (if it were mine) I would buy another battery in this situation based on the fact that the current one is of unknown age. The logic I'm using is that the battery will need to be replaced sometime fairly soon anyway, so it won't be a waste of $$ in the long run, even if it doesn't fix any of the current issues (assuming the intent is to keep the vehicle).

With a new battery installed, I'd be looking for the load test to show good, steady voltages, and that would confirm the existing battery is bad. But if the load test results don't change, then the problem in the charging system is somewhere else.

[Enjoyneering]

So you have a problem with o2 sensor and 5 more codes from day one, and you are still wondering why you are getting low mpg?

[Slow-But-Fast]

Hello! I'm sorry I haven't been able to get back to you. Frankly, there's hardly any time to retest the voltage again with someone, but now I've been getting more time. On 2/27/17, I tested the voltage by myself. The voltage did fluctuate. Here's what I got:

Voltage before engine start: 12.90-12.95volts
(Waited about 10 seconds)
Engine on(radio plays automatically): 14.65
Heat on Max; level fan speeds:
1: 14.55-14.60
2: 14.55
3: 14.52-14.55
4: 14.45-14.49
Recycle air on: 14.43-14.46
Ac on: 14.41-14.43
Rear window heater: 14.43-14.46
After about 20-30 seconds: 14.00
Another 20-30s: 13.85
Another 20-30s: 13.60-13.40
Front lights on: 12.90
30s later: 12.60
30s later: 12.57-12.60
Highbeams lights on: 12.50
30s later: 12.45
Hazard lights on w/ highbeams: 12.30
30s later: 12.46-12.48
Inside light on: 12.45
30s later: 12.40-12.43
Rev for a few seconds. Jumped to atleast 12.60 then fell quickly to 12.50
~30s later: 12.37-12.40

Turned everything off, except engine: 12.35-12.38



I noticed there isn't anymore rough driving, probably because I've been accelerating slower. Surprisingly, I get better mpg when I speed without accelerating. For example: when I drive 80mph for about an hour, I get about 27mpg rather than 22mpg at 65-70mph.

My dad thinks its the air-fuel ratio. I also think it has to deal with my tires, since the previous owner put on 3 tires that are 8% bigger than what is recommended. This could explain why I get improper mileage readings. I play on getting tires sometime this or next week.
These tires

On 2/18/17, I changed my oil using high mileage, synthetic oil and oil filter with a K&N filter. I changed my outer tie rods with a moog brand (to try them). Changed my brake rotors and ceramic pads at 142,930miles.

I have to check again, but on 2/27/17 I got codes:
P0134, P0133, P0131, P0138
Pending:
P0134, P0133


As for Enjoyeering, I already replaced my o2 sensors, I read other forums that replacing the o2 sensor temporarily solved the problem. I think something else is causing the o2 sensors to fail. Which could be the air-fuel ratio.

[2010AveoLT]

P0134 means the upstream O2 sensor isn't doing squat (the Voltage SHOULD be fluctuating in a sine wave type pattern) P0133 means the upstream O2 sensor is being slow to respond to changes in air/fuel ratio in the exhaust stream; P0131 means the Upstream O2 sensor isn't getting enough of the 5 volt reference signal from the ECM, and P0138 means the Downstream O2 is getting TOO MUCH voltage! from those codes I see, as well as the voltage measurements you have provided; I'm going to side with what everyone has said already, and say that Something isn't right with your charging system or there might be an intermittent connection between the cells in your battery. I would probably scrutinize the battery first; because a battery is cheaper than an alternator (MUCH Cheaper in my case, a 2009+ alternator costs $171; although for an 04-06, an Alternator is nearly $200!)

[Dixy]

[QUOTE= I already replaced my o2 sensors, I read other forums that replacing the o2 sensor temporarily solved the problem. I think something else is causing the o2 sensors to fail. Which could be the air-fuel ratio.[/QUOTE]

Did you replace with aftermarket sensors?
They are known for quick failure, if thy fit at all (got similar situation with camshaft position sensot that i got from aliexpress). Also, since exaust was replaced, check for switched connectors, if they are even possible to misplace. Check for good ground at the connectors for O2 sensors. Also, the conncetor harness is not supposed to be soldered, as sensors use wire continuety as a passive refference (also tried by me, on a Lanos 1,6sx oxy sensor). Instead of soldering, you could use metal crimp commectors, and only they will work. I hardly doubt that battery/alternator problem would be solely cause for O2 sensor failure, but it is worth to check and fix, so do start from there. Get a simple OBDII scanner (ELM type or so) and graphing software (as Torq for example), and check for oscillating voltsge at bank1 sensor 1 O2. If there is no oscllation of voltage, concider replacing O2 again after checking integrity of wiring and harnesses. Air/fuel mixture is determined of these sensors (along with baro, coolant temp sensor, IAT), so it is not the cause of problem, it is a symptom.

[Slow-But-Fast]

So I should:
1- Check for any loose wires that could provide unnecessary connections?
2- Replace the Battery
3- Check the O2 sensor's ground
4- Possibly replace O2 sensors


They were aftermarket O2 sensors. But shouldn't that not matter if there were issues before I replaced the o2 sensors? What would you recommended to replace them?

I have manually created a graph with a video of voltage over time awhile ago. (See attachment) The time interval is 0.3 of a second.

I will probably get the Torq app, because it would make things easier haha

[Dixy]

Do not change battery until you check grounds on your car. Look at the picture and find the grounding points and check wires, for maybe they are nicked or broken or simply loose... Clean connection points and tighten them well. Also put your battery on a charger, and see what will happen after charging - will it loose charge spontaneously or not. If it does not, then you have an electrical problem of grounding kind and you have to find it. I would check that wires for oxy sensors that go to ECU are clean and intact.

[Slow-But-Fast]

Are the ground points in the picture whereever there is a G? And some number? Should there be a certain reading/measurement?

[Dixy]

Yes, grounds are marked with G. Check with DVOM for zero resistance, or good continuity between battery ground and grounding points. It would be best to do this when circuits are loaded. Test for voltage drop between battery ground and ground points. Read this as a guide how to do it:
http://www.fme-cat.com/Docs/1519.pdf
Generally, you should see less then 100 mV of voltage drop...
Keep us posted what you found.

[Slow-But-Fast]

Ok I'll try it once this snow passes lol whenever that is!