O2 sensor and Seafoam

Tahdig_siah

Tahdig_siah

TJ Enthusiast
Joined
Apr 22, 2023
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Location
Ohio
I watched a video by Scotty Kilmer, he went through different steps to figure out why a 2007 Corolla was sluggish. Long story short, a can of seafoam to clean the injectors was the solution. Looks like car's O2 sensor was problematic. I had an old Chrysler mechanic tell me to drive my 2000 TJ, 2.5L w/110k mi , with a tank of seafoam for a few days and clear the check engine light a few times and the issue may resolve.
My issue is the downstream O2 sensor that OBD2 is showing as the problem. As some of you know, I ordered Kroil Penetrating oil in hopes of removing the stuck skid plate bolt.
what do you all think?
 
The use of Seafoam to clean injectors is a common practice and can improve engine performance. It's possible that the sluggishness in your 2007 Corolla was a result of dirty injectors, which were cleaned by the Seafoam treatment. As for your 2000 TJ with the downstream O2 sensor problem, it's worth giving Seafoam a try as it may help to clean up any carbon deposits in the engine that could be causing the problem. However, it's important to note that Seafoam is not a guaranteed solution and there could be other underlying issues with the sensor that need to be addressed. As for using Kroil Penetrating oil to remove the stuck skid plate bolt, it's a good choice as it's a high-performance lubricant that can help loosen rusted or frozen parts. Just be sure to use caution and follow proper safety procedures when working with any lubricants or chemicals.
 
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I already have the O2 sensor (bought a brand based on the recommendations on this wonderful forum). I will be working on it sometime next week. Just wanted to get everyone's take on effects of dirty fuel injectors on O2 sensors.
 
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What I found worth noting is that live data on OBD2 shows 1v for both sensors (I only have 2 sensors as its a 4 cyl). 1v I believe means faulty sensor (or harness). However, I only get the code for the downstream sensor...
 
Tahdig_siah said:
I already have the O2 sensor (bought a brand based on the recommendations on this wonderful forum). I will be working on it sometime next week. Just wanted to get everyone's take on effects of dirty fuel injectors on O2 sensors.
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It's highly unlikely you have dirty fuel injectors. In 1989 the EPA mandated that all grades of gasoline have sufficient quantities of fuel system cleaners to keep the components clean.

My personal experience confirms that after asking a whole bunch of GM, Ford, and Jeep mechanics when was the last time they had seen a dirty fuel injector. I was able to do this since I had 15-20 dealerships as customers when I was with a company that installed lifts and big tires on some of their new trucks and Jeeps. The old mechanics all said it had been many years since they had last seen a dirty fuel system or fuel injector, the newer mechanics had never seen one. They all agreed the fuel injection system cleaning services their service writers pushed for $115-120 was not needed and was mostly pure profit for the dealership.
 
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Jerry Bransford said:
It's highly unlikely you have dirty fuel injectors. In 1989 the EPA mandated that all grades of gasoline have sufficient quantities of fuel system cleaners to keep the components clean.

My personal experience confirms that after asking a whole bunch of GM, Ford, and Jeep mechanics when was the last time they had seen a dirty fuel injector. I was able to do this since I had 15-20 dealerships as customers when I was with a company that installed lifts and big tires on some of their new trucks and Jeeps. The old mechanics all said it had been many years since they had last seen a dirty fuel system or fuel injector, the newer mechanics had never seen one. They all agreed the fuel injection system cleaning services their service writers pushed for $115-120 was not needed and was mostly pure profit for the dealership.
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Good to know Jerry. Ok, I will change that downstream O2 sensor and go from there.
So, all these people changing their fuel injectors from stock to the 4 hole, is really not a necessity then. I had though of doing in the past...
 
Tahdig_siah said:
Good to know Jerry. Ok, I will change that downstream O2 sensor and go from there.
So, all these people changing their fuel injectors from stock to the 4 hole, is really not a necessity then. I had though of doing in the past...
Click to expand...
There's no benefit to so-called "performance" fuel injectors like 4 hole models. Those that are capable of spraying more fuel are prevented from doing so by the PCM which simply shuts them off sooner so the correct air-fuel ratio is maintained.

On replacing your downstream O2 sensor, stick strictly to an NTK, NGK, or Mopar O2 sensor. All of those are made by NTK. Bosch and aftermarket O2 sensors are well known to not work properly in our Jeep engines.
 
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Jerry Bransford said:
There's no benefit to so-called "performance" fuel injectors like 4 hole models. Those that are capable of spraying more fuel are prevented from doing so by the PCM which simply shuts them off sooner so the correct air-fuel ratio is maintained.

On replacing your downstream O2 sensor, stick strictly to an NTK, NGK, or Mopar O2 sensor. All of those are made by NTK. Bosch and aftermarket O2 sensors are well known to not work properly in our Jeep engines.
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Yes I bought 23099 NTK after reading about them on this forum. I just hope its not seized like my skid plate is. Waiting on Kroil and going to torch the two stuck bolts.
 
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Tahdig_siah said:
What I found worth noting is that live data on OBD2 shows 1v for both sensors (I only have 2 sensors as its a 4 cyl). 1v I believe means faulty sensor (or harness). However, I only get the code for the downstream sensor.
Click to expand...

Are you getting this number from a data PID, or are you graphing the o2? If you're getting it from a data PID, you're assumption that it's bad is wrong. I'm guessing the code you're getting on the downstream is a heater circuit code anyways, which doesn't have anything to do with that 1v number you're talking about, and if it is a heater circuit problem, it's certainly nothing that seafoam will remedy.
 
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Jerry is correct about the cleanliness of the fuels and fuel systems on current vehicles. The fuel filters in the tanks are much better than the old inline paper filters too. Most of the junk you add to the gas tank does nothing to improve your vehicles performance. If you wish to have your system cleaned find a shop that uses "BG" products as in my opinion they are the best in the industry but don't expect much change in the vehicles performance.
 
ItchyDong said:
Are you getting this number from a data PID, or are you graphing the o2? If you're getting it from a data PID, you're assumption that it's bad is wrong. I'm guessing the code you're getting on the downstream is a heater circuit code anyways, which doesn't have anything to do with that 1v number you're talking about, and if it is a heater circuit problem, it's certainly nothing that seafoam will remedy.
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I am getting P0138: O2 sensor circuit high voltage bank 1 sensor 2
and P0141 O2 sensor heater circuit bank 1 sensor 2

My OBD2 scanner where I get my info from is a Foxwell NT201
 
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