O2 sensors don't work after 0411 swap L31 Vortec

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L31MaxExpress

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Sorry Not trying to be dumb But these are the two im using. (Circled in red.)
Like I mentioned before im not using 1, and 2, in the pic.


This is the style connector the pre cat o2s use and thats what im currently using. (Not that specific o2 in the pic)
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I never said you were. I was just covering the basis since you were the one asking about it. First step to diagnosing the problem is knowing what was done.
 

MrOverCast

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This is beginning to sound more like an issue with the powetrain swap into the square body than the 411 itself. May be better to look at it from that perspective.
No. it is not an issue with the powertrain swap, the entire harness was torn apart and checked for wire damage etc, and everything was fine,

This person had this issue to but it doesnt solve my problem. I have many questions to this.
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It it a 0411 issue. its probably the fact the ecu came out of a 2002 suburban with a 5.3 that more than likely had case ground o2 sensors. this is a common issue it seems like but my problem is no one uploads a solution. the engine runs fine at operating temperature but it just runs rich because there's no o2 signal

There has to be somebody out there that has ran into this problem and came up with a good solution besides hacking up the harness.
 

Supercharged111

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No. it is not an issue with the powertrain swap, the entire harness was torn apart and checked for wire damage etc, and everything was fine,

This person had this issue to but it doesnt solve my problem. I have many questions to this.
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It it a 0411 issue. its probably the fact the ecu came out of a 2002 suburban with a 5.3 that more than likely had case ground o2 sensors. this is a common issue it seems like but my problem is no one uploads a solution. the engine runs fine at operating temperature but it just runs rich because there's no o2 signal

There has to be somebody out there that has ran into this problem and came up with a good solution besides hacking up the harness.

If you had the 5.3 PCM fully flashed with a 5.7 van tune there shouldn't be any issue, not that I'm aware of anyway. If you didn't then it shouldn't run at all.
 

Supercharged111

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No EGR or emissions stuff. im using holley EFI single plane intake

Ahh I missed that entirely. The way your exhaust looked was how mine looked when I didn't properly follow the EGR procedure on the 411 swap. So ft starters, your injector trajectory is off from stock which will cause some transient fueling issues, but that's tunable. What else is done to the motor?
 

MrOverCast

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Ahh I missed that entirely. The way your exhaust looked was how mine looked when I didn't properly follow the EGR procedure on the 411 swap. So ft starters, your injector trajectory is off from stock which will cause some transient fueling issues, but that's tunable. What else is done to the motor?
What is injector trajectory?

The engine is actually a stock 350 pre 89 non vortec. That I put a vortec engine harness on. I just say I got it out of another vehicle because people stop replying when I tell them what I did to the engine. So stock 350 originally carbureted with a vortec harness on it. With 24 lb hr injectors and a 1000cfm holley throttle body
 

Supercharged111

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What is injector trajectory?

The engine is actually a stock 350 pre 89 non vortec. That I put a vortec engine harness on. I just say I got it out of another vehicle because people stop replying when I tell them what I did to the engine. So stock 350 originally carbureted with a vortec harness on it. With 24 lb hr injectors and a 1000cfm holley throttle body

Was the 411 tuned for the injectors? And are they 24# at whatever pressure you're running them? What pressure are you running them at? In the absence of a donkey d1¢k cam I would think, even with the weird combo, that it would run OK as long as you gave the 411 the correct info to start with. How does it run if you just unplug the O2 sensors?
 

MrOverCast

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Was the 411 tuned for the injectors? And are they 24# at whatever pressure you're running them? What pressure are you running them at? In the absence of a donkey d1¢k cam I would think, even with the weird combo, that it would run OK as long as you gave the 411 the correct info to start with. How does it run if you just unplug the O2 sensors?
The 0411injector data was set for 3.00 grams/sec for the 24 lb/hr injectors using tuner pro. Injectors are running at 60 psi constantly. And I never tried that. I assume it wouldn't care but I could give it a try.
 
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