Can I change the upstream O2 sensor without replacing the converter gasket?

Hello DAVENOOB,

Unfortunately, you cannot re-use the gasket. The area needs to be cleaned well and all old gasket material removed.

Also, when you start it after replacement let it warm up while idling. The gasket will seat itself once it gets hot. If you rev the engine or snap the throttle before it has warmed up it can damage the gasket and cause it to leak.

Hope this helps.

Thank you,
Brendon

Hello DAVENOOB,

You're welcome.

The gasket is called an Exhaust Manifold Gasket.

The part number for both sides should be, 20893953.

Before replacing, let the engine warm up so the pipe is hot and use an Oxygen Sensor Socket. These don't normally come out easy so the socket will help and keep it from stripping.

Here is a link to a good socket. You should need a 22mm:
https://www.ebay.com/itm/394440429936?var=0&mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338590836&toolid=10044&customid=86ad6777fd0216422080039222ca888b

I have included a picture from the GM catalog as well as removal/installation procedure for you. This procedure will be the same for all four.

From what I can see on my end at least, if you use the socket in the above link, you should not need to remove anything else to replace these, at least for the exhaust. Meaning you won't need the above-mentioned gaskets.

You can send me the code(s) and I can try to help you figure out what is going on if you would like. You shouldn't need all four at the same time.

If you don't have a code reader, places like Autozone and other parts stores will read the codes for free for you.

Hope this helps.

Thank you,
Brendon

Hello DAVENOOB,

Okay. Sounds good and you're very welcome. Happy to help.

Thank you,
Brendon

Hello DAVENOOB,

I apologize I didn't get back to you sooner.

Generally, a bad EVAP Vent Solenoid isn't likely to cause any noticeable symptoms, most of the time. Except for an illuminated check engine light.

However, it is possible, and I never rule anything out completely.

Let's start by gathering as much information as possible.

I know you said it seems like it is running thin? But gets better when cold and the hotter it gets the worse it gets.

Can you elaborate for me on these? What other issues are you experiencing?
What do you mean by running thin? Do you mean it seems like you have a loss of power?

When you remove your gas cap are you hearing an air whooshing like sound? Like pressure escaping?

When you fill it with gas, does the pump keep shutting off like it's full?

When are you noticing these performance issues?

If the vent solenoid is not venting, the fuel tank can pressurize. There is a solenoid on the intake called the EVAP Purge Solenoid. This is only open under certain conditions. If the fuel tank is pressurizing it could cause a rich condition when that solenoid opens.

As we know air expands and contracts depending on temperature. So, this could explain why the symptoms get better when it is colder, because there is less pressure in the tank.

Are there any certain conditions that the symptoms seem to arise, like for instance cruising on the highway or going uphill? How about driving slowly around town? How about passing or getting on the highway?

Any previous issues with the fuel system or work performed prior to this issue?

Because we don't have scan tool to look at the data the PCM is collecting, getting as much precise information from you will help a lot.

Taking it for a test drive to collect information would hurt either if you have the time.

While you are thinking about that I am going to get a couple test procedures prepared for you for that code that was found to try if you are willing.

We will need to see if the solenoid itself is faulty or something else is causing it.

Thank you,
Brendon

Hello DAVENOOB,

Okay. Thank you so much for the great information. I appreciate it. I have another customer who has a similar issue.

I am trying to get some more information out of them right now to see what might match up with yours in case they are related.

So, we will see if we can get a little help there.

The vent solenoid usually we would use a scan tool and use it to turn the vent solenoid on and off and see if we can hear it clicking. That would tell us that not only the circuit and computer are working as they should but whether the valve is good or bad.

How comfortable are you with testing electrical components? Do you have a multimeter or a test light?

Thank you,
Brendon

Hello DAVENOOB,

Okay, awesome. It is hard to tell in the picture you sent. Can you tell me what that is? Is that for 12v systems? Can you check for power with it?

I apologize, I just want to make sure the tests I send you match the equipment you are using.

Thank you,
Brendon

Hello DAVENOOB,

Oh ok. Unfortunately, that is for 120-volt systems. We are working with 12 volts, so it isn't going to work for us. It probably only goes down to 50 volts.

Even if it did a test light won't tell us voltage just whether voltage is present or not.

Let's see if the solenoid is good or bad. It is usually mounted in the left rear quarter panel behind the back wheel. There was an update GM did that moved it so if it isn't there look by the filler neck or up closer by the body. I added some pics to help you identify it.

You are going to take a fused jumper wire from the battery positive all the way to the vent valve solenoid.

We are going to run straight power to this thing and see if it moves.

Remove the connector from the valve.

Make a ground with 14-gauge stranded wire and attach to frame or known good ground. Then using an alligator clip and attach the wire to one of the prongs on the solenoid.

Then take another alligator clip and attach it to the other prong on the solenoid and then quickly touch the fused jumper to the alligator clip. This will make a small arc so be careful, but this arc can damage the terminal. That is why we are going to attach the alligator clip and touch the wire to that.

Once this is done you should hear a soft thump kind of sound. This is the solenoid moving. That means it at least moves. So that means our issue is likely something else in the system and further testing is required.

Insulated alligator clips are best but uninsulated ones can be used with caution. They must never touch. Using electrical tape around the alligator clip and making a cut so it can still open and close will work to insulate the clip.

If it is easy enough you can remove the vent valve from the vehicle and bring it up to the engine compartment and test it the same way just instead use battery negative as ground. But then if it works you removed a working part for no reason. So, I will leave that up to you.

10†15-amp fuse is good enough for the jumper wire.

Let me know if you have any questions.

If we can find out if this thing is the issue or not, then we can proceed from there.

If not, from here we will need a multimeter to check the computer side and see if there is a wiring issue.

Here is a link to one I own. It is inexpensive and accurate:
https://www.homedepot.com/p/Klein-Tools-600-Volt-Digital-Multi-Meter-TRMS-Auto-Ranging-Temp-MM420/320822810

Thank you,
Brendon

Hello DAVENOOB,

Okay, sounds good and thank you very much I appreciate that. Happy to help! Yup, I am here 7 days a week. I run my own business so sometimes it might take me a little bit to respond though.

Also thank you very much for any donation, we really appreciate it!
Here is the link for you:
https://www.gofundme.com/f/help-us-help-others-get-back-on-the-road?utm_campaign=p_cf+share-flow-1&utm_medium=copy_link&utm_source=customer

Thank you so much!

A multimeter is best, that way we can check voltage and resistance.

The one in the picture looks like it should be fine.

Main things you will want to look for in a meter in my opinion is that it is Auto-Ranging but should still have a button that says "Range", so you can change it if you need to, backlit screen, and an audible continuity tester.

None of these are necessary but nice to have.

Looks like the one in the picture has an audible continuity tester so I would say that one would be good enough. I have never used that brand though. It is manual ranging, which is fine, you just have to make sure it is in the right setting.

This video will show how to use a manual ranging meter and how to set it:

https://youtu.be/xoH3COn57JA?si=_eQTrLhDP9Q63dqp

Fast forward to around 4 minutes.

If you pick one up at the store, I recommend grabbing one from the back of the shelf because people look at them, then drop them accidentally, look around and put it back. Then you get it home and go to use it and it is reading all over the place.

Grabbing one from the store is better anyways so you can return it quickly if there is an issue.

Hope this helps. I will get some tests together for you and send them over as well.

Thank you,
Brendon