Tonyrodz's Tahoe Build Thread

[Tonyrodz]

Won’t see it on live data if it’s intermittent unless you watch live data while you’re driving.

Ok. Gonna drive it to work tomorrow, I'll see how it acts.

 

[Snowbound]

its says bank 2 is lean. really lean. like vac leak lean, but that would be both banks showing lean. so likely a wet o2.

a neg number is rich, pos numbers are lean. so you got a +18 long term and a -31 on the short term, thats the pcm trying to make it right, but it cant win this fight lol

Not being a smart a$$ here so don’t take it that way. Positive numbers are adding that percentage of fuel to the base table. Negative numbers are subtracting percentage of fuel from base table. Lambda 1 is stoich meaning perfect air fuel ratio. Most think in terms of 14.7:1 AFR. Which is true for gasoline. So let’s just stay with that. Anything above 14.7 is lean, anything below is rich. I think that’s where you got the positive lean and negative rich from.

But I’m not understanding the wet O2 theory. Wet as in the wires got wet, interfered with the signal back to the ECM? Or O2 element got wet, meaning the entire exhaust system filled with water? Either way, I don’t think that’s gonna happen. What I have seen happen is hot exhaust hits cold water and as George Costanza from Seinfeld explains, shrinkage from being in the pool. I’ve seen bolts snap at collectors or flanges causing exhaust leaks where the O2 is not getting the entire stream of exhaust past it giving it a false lean condition. Sometimes a hole or crack in exhaust doesn’t leak because the velocity of exhaust gasses going past exposure actually creates a low pressure and can create a vacuum effect sucking outside air into the system. This also gives a false lean condition. Think like a Venturi.
Or could be just a lazy O2 sensor. Watch the data on the O2. Is it fluctuating at the same rate as the other bank? Is staying within a 200-250MV swing? With the right scan tool, you can command EGR to open and watch O2 data. If no EGR like my vehicles, command injector to shut off, watch data. There’s many test to check what’s going on. No scan tool, swap O2 sensors from one side to other. If issue follows the O2, there’s your problem. If issues stays with the same bank, then suspect fueling.



Sent from my iPhone using Tapatalk

 

[Tonyrodz]

Not being a smart a$$ here so don’t take it that way. Positive numbers are adding that percentage of fuel to the base table. Negative numbers are subtracting percentage of fuel from base table. Lambda 1 is stoich meaning perfect air fuel ratio. Most think in terms of 14.7:1 AFR. Which is true for gasoline. So let’s just stay with that. Anything above 14.7 is lean, anything below is rich. I think that’s where you got the positive lean and negative rich from.

But I’m not understanding the wet O2 theory. Wet as in the wires got wet, interfered with the signal back to the ECM? Or O2 element got wet, meaning the entire exhaust system filled with water? Either way, I don’t think that’s gonna happen. What I have seen happen is hot exhaust hits cold water and as George Costanza from Seinfeld explains, shrinkage from being in the pool. I’ve seen bolts snap at collectors or flanges causing exhaust leaks where the O2 is not getting the entire stream of exhaust past it giving it a false lean condition. Sometimes a hole or crack in exhaust doesn’t leak because the velocity of exhaust gasses going past exposure actually creates a low pressure and can create a vacuum effect sucking outside air into the system. This also gives a false lean condition. Think like a Venturi.
Or could be just a lazy O2 sensor. Watch the data on the O2. Is it fluctuating at the same rate as the other bank? Is staying within a 200-250MV swing? With the right scan tool, you can command EGR to open and watch O2 data. If no EGR like my vehicles, command injector to shut off, watch data. There’s many test to check what’s going on. No scan tool, swap O2 sensors from one side to other. If issue follows the O2, there’s your problem. If issues stays with the same bank, then suspect fueling.



Sent from my iPhone using Tapatalk

Wow, who would've ever thought mechanics would've gotten so complicated--computer wise. Thx for the info @Snowbound. I'm gonna drive it to work a few days to see how it acts.

 

[Scottydoggs]

Not being a smart a$$ here so don’t take it that way. Positive numbers are adding that percentage of fuel to the base table. Negative numbers are subtracting percentage of fuel from base table. Lambda 1 is stoich meaning perfect air fuel ratio. Most think in terms of 14.7:1 AFR. Which is true for gasoline. So let’s just stay with that. Anything above 14.7 is lean, anything below is rich. I think that’s where you got the positive lean and negative rich from.

But I’m not understanding the wet O2 theory. Wet as in the wires got wet, interfered with the signal back to the ECM? Or O2 element got wet, meaning the entire exhaust system filled with water? Either way, I don’t think that’s gonna happen. What I have seen happen is hot exhaust hits cold water and as George Costanza from Seinfeld explains, shrinkage from being in the pool. I’ve seen bolts snap at collectors or flanges causing exhaust leaks where the O2 is not getting the entire stream of exhaust past it giving it a false lean condition. Sometimes a hole or crack in exhaust doesn’t leak because the velocity of exhaust gasses going past exposure actually creates a low pressure and can create a vacuum effect sucking outside air into the system. This also gives a false lean condition. Think like a Venturi.
Or could be just a lazy O2 sensor. Watch the data on the O2. Is it fluctuating at the same rate as the other bank? Is staying within a 200-250MV swing? With the right scan tool, you can command EGR to open and watch O2 data. If no EGR like my vehicles, command injector to shut off, watch data. There’s many test to check what’s going on. No scan tool, swap O2 sensors from one side to other. If issue follows the O2, there’s your problem. If issues stays with the same bank, then suspect fueling.



Sent from my iPhone using Tapatalk

exactly, neg is rich. pos is lean....your saying the same thing but backwards to me. we dont need to explain how the pcm interprets things, just what it means in the end.

plugs get wet too. weather tight plugs or not. old wires can also get wet and take a day to dry out and yes cause the signal to not get to the pcm. ive swamped many cars and trucks. you can expect this to happen sometimes when you take a chance going through 4 foot of water.

 

[Tonyrodz]

exactly, neg is rich. pos is lean....your saying the same thing but backwards to me. we dont need to explain how the pcm interprets things, just what it means in the end.

plugs get wet too. weather tight plugs or not. old wires can also get wet and take a day to dry out and yes cause the signal to not get to the pcm. ive swamped many cars and trucks. you can expect this to happen sometimes when you take a chance going through 4 foot of water.

4 foot??

 

[Scottydoggs]

4 foot??

ive been 4 foot deep before maybe even 5. lol water was cresting my windshield and over the door glass of my 03 gmc. it of course ran like crap for set the check engine light off.

one of them times i was glad to of had the stock intake tube still. them dumb dead end tubes are there to catch water. mine was full, filter was wet ect ect. let it sit a day and all was good the next day after it dried up good.

 

[Tonyrodz]

ive been 4 foot deep before maybe even 5. lol water was cresting my windshield and over the door glass of my 03 gmc. it of course ran like crap for set the check engine light off.

one of them times i was glad to of had the stock intake tube still. them dumb dead end tubes are there to catch water. mine was full, filter was wet ect ect. let it sit a day and all was good the next day after it dried up good.

You're crazy lol! Water cresting the windshield--damn!

 

[Scottydoggs]

You're crazy lol! Water cresting the windshield--damn!

you should have been there lol its a dip in the road where it just drops 4-5 foot. the flooded area has to be a good 100 foot long, deepest part 40 foot of that.

this truck came sitting high already, then i added 33's and a 2 inch lift, so it was deep. tossed it in 4 low, drove in brake tq'ing it as the tail pipe was fully under water fast, then as it got 1/2 way up the doors i was like this might have been a bad idea, then the ass end started to float. (pick up truck) glad i had it in 4 low at this point, then the water was over the hood and hitting the glass. she kept on plowing through like a boss. right up till it came out the flood, then it started to run like crap. lucky i was blocks from home.

i did get water in the front diff. talk about a milkshake lol only bad thing that did happen.

 

[Tonyrodz]

you should have been there lol its a dip in the road where it just drops 4-5 foot. the flooded area has to be a good 100 foot long, deepest part 40 foot of that.

this truck came sitting high already, then i added 33's and a 2 inch lift, so it was deep. tossed it in 4 low, drove in brake tq'ing it as the tail pipe was fully under water fast, then as it got 1/2 way up the doors i was like this might have been a bad idea, then the ass end started to float. (pick up truck) glad i had it in 4 low at this point, then the water was over the hood and hitting the glass. she kept on plowing through like a boss. right up till it came out the flood, then it started to run like crap. lucky i was blocks from home.

i did get water in the front diff. talk about a milkshake lol only bad thing that did happen.
View attachment 225372

She was a champ! Any water get inside? I would've shit a brick if it was me!

 

[Scottydoggs]

She was a champ! Any water get inside? I would've shit a brick if it was me!

not a drop. door seals held up like a boss too. when it went over the door glass i thought for sure there would be water getting inside, inside the door may have gotten damp but nothing more then a hard rain would have done to it.

i wish phone cams were in play back then, the evidence there would be out there lol.