O2 sensor trouble ( I think it's solved )

[Momohenri]

Hi, I just replaced the O2 sensor, I have code 42 rich system, if I reverse the two sensor wires I have 41 lean system, any ideas?
In addition I have code 13 idle too high but I can't adjust it, I have a new IAC and when I put the old one back the idle is a little lower but still too high, I don't know if it's because of the IAC or the tps.
I also have the oil warning light that comes on at idle, it goes off if I give a little gas, the level is good; oil pump problem?

 

[franklin2]

Code 42 means the voltage from the O2 is stuck high(too rich). If you swap the wires the voltage will go low and give the lean code. Put the wires back like they are supposed to be, but that tells you your computer is working ok.

Pull the PCV valve and see if the code goes away. Also see how much blowby you have out of the hole where the PCV goes. Sounds like the engine may be wore out.

 

[rusty ol ranger]

The high idle is likely caused by a vacuum leak...which is allowing the motor to run lean, which makes the O2 notice to much oxygen in the exhaust, which in turn the oxygen sensor is telling the ECM to dump more fuel, which is why its throwing a rich code.

 

[SenorNoob]

Either something worn severely or the wrong/old oil for the idle to be too high and have to rev it some to get the pressure light to go out. Unless you have a light hooked up to a gauge sender or something. Can you put a mechanical gauge on just to see what the oil pressure is?

 

[Momohenri]

Thanks for the advice, I'll look into it on Sunday, I'm not at home until then, can we remove the oil level sensor without emptying it? That way I'll put a pressure gauge in to see the pressure.

 

[SenorNoob]

Level sensor is in the pan. (If you have one.) It wouldn't do any good for measuring pressure. The pressure switch/sender is higher up in the side of the block. IIRC it's like 1/8 NPT already. Technically the switch is supposed to have a special socket. It's not quite regular hex. Like this: Lisle 13200

 

[franklin2]

Look for the oil pressure sending unit on the front driver's side corner of the block down low. It will probably be hidden behind the power steering pump screwed into the engine.

If it's just a small sensor, that is the oil switch style that turns on a light in the dash. If it is the large can looking thing, that is a sending unit that runs a pressure gauge. Usually the pressure switch illuminates the light when the pressure is 5lbs or less.

Along with the light coming on, you should have a noisy engine, and if you have run it, it will usually use some oil. It all goes together. It will have a lot of miles on it also. All or some of these together paint a picture.

If the engine has been rebuilt, has low miles, doesn't use any oil, you may just have a bad sending unit, or check the single wire going to it. If that wire rubs against metal anywhere along the way to the firewall, it will turn the light on as soon as it touches metal(grounded).

 

[rusty ol ranger]

Wait...

Do you have an idiot light for oil pressure? Or the idiot gauge?

If youre talking about the "check oil" light on the dash light cluster that is only for oil level. Chances are its the wireing or sensor.

I have never seen a first gen with an idiot light for oil pressure...and certainly not a 2nd gen.

 

[SenorNoob]

I have a low level and low pressure light. The pressure light is in the tach. The level is the bottom right conder of the center light panel.

I don't know if both were functional before the 4.0 swap or not. But the 2.9 did have both switches.

 

[rusty ol ranger]

I have a low level and low pressure light. The pressure light is in the tach. The level is the bottom right conder of the center light panel.

I don't know if both were functional before the 4.0 swap or not. But the 2.9 did have both switches.

My bad....i forgot about the tach cluster.

 

[Momohenri]

It's the indicator lamp as in the photo above the battery lamp which lights up in slow motion if I give a little gas the light goes out.I rechecked the oil level and it is good.
For the O2 sensor there is no longer a socket, the new sensor has three wires, 2 red and one black, I tested the different possible connections, I connected the black to the black of course and I tested the other two by reversing them, this is where I got the codes 41 or 42

 

[rusty ol ranger]

It's the indicator lamp as in the photo above the battery lamp which lights up in slow motion if I give a little gas the light goes out.I rechecked the oil level and it is good.
For the O2 sensor there is no longer a socket, the new sensor has three wires, 2 red and one black, I tested the different possible connections, I connected the black to the black of course and I tested the other two by reversing them, this is where I got the codes 41 or 42

The battery light is lighting up too? Or instead of the oil?

If the battery light is also on then you probably have a bad ground or your alternator is getting weak and possibly throwing everything off.

 

[19Walt93]

Address the oil light first, if it's running rich the oil could be diluted with gasoline.
Some parts stores- like Autozone for example- like to sell O2 sensors to fix rich or lean codes because their cheap tester says "O2 out of range." O2 out of range isn't a diagnosis, it's a symptom. I'd make sure the O2 ground is good then look for the cause of the rich code. Please switch the wires back to their original positions, clear the memory and drive it until the light comes on again.

 

[franklin2]

Yes, it's diffcult to know if the O2 sensor is lying or telling the truth. If it's the problem or just a clue to the real problem.

 

[Momohenri]

Good news, after many things that I tried, I had the idea to put the old tps back and miracle the idle is perfect but strange thing, the rich code has disappeared and the oil light no longer comes on, all that remains is to find where the clicking comes from and it will be perfect