Oxygen sensor broken?

scan for codes if none found check fuel pressure with a gauge auto parts rent it.

ARE YOU HOOKED ONLY TO THE O2 SENSOR WIRE W/ MR. VOLTMETER?

OR

ARE YOU "TAPPED INTO" THE "STILL PLUGGED IN" O2 SENSOR?

WHAT GAVE YOU THIS "BROKEN ASSUMPTION"?

THE MEDIC

sorry, I meant if the sensor is or not damaged, not broken (wire).

Anyway, to make reading a pin was placed tip and insert the sensor cable, hence the positive signal multimeter (red wire) and mass of the battery was taken.

I did check the fuel pressure. Vacuum hose connected to the pressure regulator have 37 psi. And with the hose disconnected, 47 psi.

ok pressure is good then what is the code you are having. it may be just eh heater circuit for O2 and will need to be replaced also check for a fuse

the oxygen sensor is a single cable, no heater. It does not show me any code

then replace the O2 sensor I have no further comments.

I performed the following test, assuming that I have low readings from the sensor. I sprayed wd40 in the mouth of the acceleration body, simulating rich mixing, then the readings immediately rose to over 900mV. This results in thinking of damaged sensor yet? Or what should I try?
The car did not lose power, can the sensor be the cause?
The scanner does not give me errors is OBD1

Good morning

Lets back up to the beginning.

Why are you measuring the voltage at the sensor? What issue do you have that makes you think there is a problem?

Roy

Leak power.

Got it.

The sensor will not cause a low power issue. It monitors fuel in the exhaust for fuel mapping.

https://www.2carpros.com/articles/engine-has-low-power-output

Roy

Hi. I disconnected the IAC valve, then I saw that the oxygen sensor readings started to work (random readings), I no longer had a static reading of 75 or 76 mV.

If you have a lack of power, I would check both the fuel pressure and the cat converter for being clogged.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Roy

How to check catalytic converter is clog?

You need a back pressure gauge. You remove the O2 sensor and install the gauge. Run the engine and see how much pressure. Anything greater than 1.5 lbs is a clogged converter.

Roy

engine idling or accelerating (up to how many rpm)?

Idling at 1500 rpm.

Roy

The problem with the low voltage reading of the oxygen sensor, could it be due to leakage problems in the intake or exhaust valves? Perform the test by putting a piece of paper in the exhaust, it sucks on the paper. Could you do a compression leak test?

Yes, if you have vacuum, then you may have a compression issue.

Pull all the plugs and do a compression test.

https://www.2carpros.com/articles/how-to-test-engine-compression

Roy

Engine compression test results:
Cylinder 1: 210 psi
Cylinder 2: 200 psi
Cylinder 3: 205 psi
Cylinder 4: 200 psi.
Note: The test was carried out 5 minutes after the engine had warmed up, with the throttle fully open, and 5 seconds when the ignition key was activated.

Then a compression leak test was performed. Each cylinder was placed in top dead center. the results in all the cylinders show a compression loss of 10% to 15%, due to the acceleration body and the oil level measuring rod.

Tomorrow I will test, measure the light on the intake and exhaust valves.

Okay, that is good.

Remove the oil fill cap while the engine is running and see if you feel vacuum over the hole. You should feel positive pressure coming out, not a vacuum.

Roy

I did the test in the oil filler hole, I feel blow and suction. I did it with a piece of paper.

If you feel suction, you have a leaking intake manifold gasket. There should be no vacuum at the fill for the oil.

https://www.2carpros.com/articles/replace-intake-manifold-gasket

Roy

NOTE: On models with coded audio anti-theft systems, refer to Technician Safety Information for code procedures.

1. On models with air bag system, disarm airbag system as outlined under Technician Safety Information.
2. Disconnect battery ground cable.
3. Remove air cleaner assembly.
4. Disconnect all electrical connectors, hoses, cables, fuel lines and electrical equipment that will interfere with removal of and intake manifold.
5. Ensure following are removed:
a. Ground strap.
b. ISC valve connector.
c. Cold start injector connector.
d. Throttle position sensor connector.
e. If equipped, EGR VSV and gas temperature sensor connectors, Vacuum sensor connector.
f. Disconnect wire clamp from vacuum pipe and remove engine wire from manifold.
g. Vacuum sensor hose from gas filter.
h. Fuel return hose from air pipe.
6. Remove manifold stay, then water bypass hose from air pipe.
7. Remove intake retaining bolts, ground strap, intake manifold and gasket.
8. Reverse procedure to install. Tighten to specifications. Reset audio anti-theft system, if equipped, as outlined under Technician Safety Information. On models with air bag system, rearm airbag system as outlined under Technician Safety Information.

I'll try smoking it, to see where it vacuum I will start by applying a clean carburetor. Are these techniques valid?

Not for an internal vacuum leak. If it were external, yes.

If you smoke it and you see some smoke come out of the oil fill, then yes, it is bad.

Roy

There is no smoke output from the oil filler cap.

The fact that you have vacuum says that the intake manifold is leaking into the crankcase.

Roy

The left (thick) hose is the PCV valve and the right (thin) hose is a direct connection from the valve cover to the intake manifold. This hose is the one that made me empty in the oil filling mouth. Plug both sides of this hose. I retested with a running engine no longer generates vacuum.

Okay, then you are good. Back to the catalytic converter testing.

Roy

What procedure to apply?

You need a back pressure gauge to install where the O2 sensor goes before the catalytic converter.

You run the engine at 1,200 RPM's and see what the back pressure measures. Anything over 1.5 pounds is no good.

You could also disconnect the exhaust from the manifold and drive the car as well.

Roy

To 1200 RPM 0 psi.
To 2000 rpm approximately 0 psi and 3000 rpm approximately 0.25 psi.

The next thing I would check is the timing. Check the valve timing on the belt and make sure the marks are correct.

I attached a diagram of the marks for you to check.


Roy

I check the timing of the distribution chain, it is correct.

The reason I asked is the compression was very high. That tells me that maybe the chain is advanced from the normal setting.

Roy

Could the high compression be caused by char in the combustion chamber or perhaps the cylinder cover has already been rectified?

If you are talking about carbon, yes it could.

There are top engine cleaners for that to remove the carbon around the intake valves.

I would try that because carbon will absorb the fuel and starve the cylinder of needed fuel.

Roy