Another P0430 / P0420 Thread - BlueDriver results

The code is 420 and 430..

In response to b_r_o.

If I hook up my Fusion scanner and check the cat temps when the engine if off they are near zero. When I start it, they quickly climb as things warm up. They are highest on hard acceleration. Then settle down a bit at cruising speed. Then drop when idling When you shut down but leave the ignition on, (stall it using the clutch so you do not have to turn off the ODB port) the temp drops more. In regard to temp sensors I do not know much about the sensor systems in these trucks, I am still learning. It was my understanding that the O2 sensors can output a voltage in regard to temperature. I have actually tested this with a torch and voltmeter, back in the day, that is how we tested early O2 sensors.

Attached are some of the first scans I did of cat temps.

 

I haven't heard of using a torch to test 02 sensors. I've always used a lab scope while adding rich/lean mixtures to the exhaust (introduce a vacuum leak, introduce propane).

 

I may be wrong about the cat temp, when I get to work tommorow I'll plug some of my scan tools in to my truck and see if I can get some comparison data for you guys

 

https://www.youtube.com/watch?v=o6iXNBPPhwc

This was on the early, 2 wire sensors. It was also a way to clean an oil fouled sensor. If you notice in the video, the sensor was very slow to respond to the torch at first. It took a while to get to .9 volts. But after it got really hot, it reacted much more quickly. It could be that the sensor was already very hot that made it react more quickly. I also realize it is possible the sensor COULD be reading the O2 in the torch flame???

I know I am learning a lot trying to figure out how this is supposed to work.

 

I am wondering about the exhaust leaks. I have looked really close and I cannot see any evidence of leaks. What if I use a shopvac? I could hook it up to either pressurize the pipe to make a vacuum in it. It would be easier to find leaks if I pressurize the pipe, but I do not want to blow crap from inside the pipe or converter into an open exhaust valve if, by my luck, some cylinder is stopped where the intake and exhaust valve are both open. Maybe I will just use the vacuum and burn some incense to test for leaks.

 

Naw.. just shop vac it! We want some answers! LOL

 

Bank 2 sensor 2 replaced. I can’t say I could replicate results every time to begin with, but sensor 2 does seem to be a bit more in sync with B1 now. I guess I’ll change B1 now and see what happens

 

Both sensor 2’s changed. My gut is telling me sensor 2 at B2 helped even things out quite a bit, and sensor 2 on Bank 1 helped to even things out a little bit more. No clue if this is going to solve my problem or not. Got codes reset, fingers crossed, I’ll keep you updated if/when codes pop back up again. If they do, I’m going to get some catalytic converter cleaner for my gas tank, and do a pressurized or vacuum leak test. If that fails...

 

Any luck hemmjo? Did you end up replacing both sensors? Just guessing here, but my gut feeling if I had to choose one and I were you, I would’ve picked B1 probably. Just seems like when looking at the graphs, B1 seems a little more erratic and slower to react than B2. Has your check engine light come back on?

2 days and about 200 miles after replacing sensors, the CEL has not come back on and no pending codes. I’ve been fighting this for too long to get my hopes up, but it’s a good sign.

 

My light did come back on after installing the B2S2 sensor after maybe 40 miles of driving around town with a couple of short freeway stints.

I can only graph 4 values, 2 in each window, at one time. The first test drive I did, with all of the original sensors is shown in post #3 of this thread. I was graphing B1 in one window and B2 in the other. The 4 sensors are all mapped at the same time. During that test drive, the B1S1 values show the same up/down trends, with B1S1 being more smooth and B2S1 showing a more quick response. Both S2 values are almost identical during that test. I have learned since that test, that my scanner has a has a smoothing function, I am not sure if that may have been active for the B1S1 sensor resulting in the smoother line.

I choose to replace the B2B2 sensor simply because it was easier to get too, and because both of the graphs from post #3 looked so close. Since one of your S2 looked so similar to mine and one was so different, I was not sure if mine were both bad, or both good.

The graphs in post #17 were done after that sensor was replaced. I should have graphed the same data in the same manner as I did the first test, but I thought it would be a good idea to get the cat temps and the sensors for each bank together. So the data in post #17 was collected at different times for each bank. The first, B2 was done in one direction, with very little traffic, B1 was collected in the other direction, traffic was an issue during that test.

Bottom line is I still have both 420 and 430 codes. I do not get the code during sustained highway driving, it has only showed after city driving. However I have seen the codes "pending" after a highway trip.

I do fear my cats may be bad.

 

I had the 420 code and it turned out to be a bad gasket between the cats on the passenger side

 

Interesting...
Couple thoughts: you said you changed bank 2 sensor 2, that is your driver side, correct? I say that because my driver side was much harder to get to because of the 4wd. Bank 1 on passenger side was cake.

I might suggest putting both sensors 1’s and both sensor 2’s on overlapping graphs, so you can compare how each sensor of the same type is reacting and look for a lazy sensor or whatnot. I got improvement in sensors matching each other better after replacing both sensors, so might not be a bad idea in your case. Well can’t hurt.

One thing I noticed when playing with my graphs was that I did not need to be driving to test the sensors. In fact I got the most consistent results by simply starting it and letting it idle in front of my house, and revving it a bit to watch reactions. You can watch the sensors warm up and start reacting, And pretty consistently at about the 25 minute mark they started oscillating up and down like a waveform. If I hit the accelerator (after the 25 minute mark) they would both jump up and down somewhat erradicly while I was accelerating, and after letting off the accelerator they would go in a straight line for another couple minutes, then would return to the oscillating up-and-down waveform. If you can watch them go into that kind of idling waveform, that was the best way I was able to compare mine. One of my graphs b1s2 was flatlined while b2s2 was going up and down. I assumed b2 would be the problem sensor because I thought it’s not supposed to be going up and down very much, and the code that I’ve been fighting much more than the other is B2, p0430... but after replacing both sides, both are going up and down, but match pretty well now, so I guess this is normal?

Another thought is to check out your freezeframe data on the codes. Should tell you vehicle speed and rpm’s at the time the code got set. My codes seem to trigger most often when cruising 45-60 mph on highway.

 

How did you find the bad gasket? Just by feeling around the connection by hand or did you use smoke or something nearby to see movement?

 

I spotted some soot. As i was under there for the umpteenth time. Swapped sensors... Torqe app graph showed bank 2 nice and smooth. Bank one was all over the place.

Edit #2, my thread on this issue...
https://www.tacomaworld.com/threads/o2-sensor-removal-wtf.454696/

 

OOPS, All of the old school engines I grew up working on were cyl #1 front left (driverside). SO, switch the bank #'s in all of my posts.

I have to get to a job out of town, will be unable to respond for a few days.

 

Lol... Time to do some post editing...

I'm old school and was taught that the cylinder that was most forward on the block was #1.

 

Same with me. I have not yet had one of these apart, I did not pay any attention to that..... just assumed. That is why it is good to talk like this...

 

Awwwww snap!! Mpg immediately before changing oxygen sensors = 15.2. Just calculated a fresh tank of gas, 17.5 MPG. Another good sign. The best mpg by far that I’ve seen in 5ish years of owning this truck.

 

I read through your thread, I think I came across it around a year ago when I first started fighting this problem. I had replaced all my gaskets on my exhaust connections when I did my head gasket replacement, and I had also gone through with a cigarette nearby and checked all the connections, and felt around the manifold when the engine was cold but running and did the best I could with a cigarette nearby for that area as well. Couldn’t find anything.

Some of the problems you came across with the other guys doing your engine swap is exactly why I prefer not to let anyone else touch my vehicle! Torching those bolts is sad, I know the bolts for the bracket are pain in the hole to get to, but still...

I struggled to get my O2 sensors out a little bit as well, I bought a deep oxygen sensor socket, but it didn’t fit. I ended up using a 7/8” box end wrench because I didn’t have a 22 mm, and broke it loose by using another open end wrench hooked into it as a cheater. Have you ever use that method? If not, I’ll take a picture for you on how to set them together, its a handy trick I’ve used many times over the yaers.

 

I have the 22mm box wrench and slipped it right on. It came out... With a little from my nsbfh. Lol