2002 Express Van 5.7 Dual Exhaust to Single Exhaust.

So new to this forum, so Hi everyone. I thought I'd be able to do everything I needed without having to ask a question, but I'm a little stumped on this one.

I have a 5.7L L31 Engine with a 4L60E sitting in a jeep, currently running off of the Blackbox PCM, I had the guy over at LT1Swap do the PCM, and it works great. But my intent is do the 0411 swap, I want to mostly be able to make changes on it myself using tunerpro, mostly gear changes, and tire changes to start with.

So in getting everything ready for this swap, I've already gotten the PCM to program properly, so no issues there. I'm working on the adjustments to the 2002 Express Van Bin file that's commonly used for this kind of swap. However, that Bin file is set up for dual exhaust with two Cats, and it was not practical to install two cats in my 89 Jeep. So I installed single exhaust with one cat, and asked the LT1swap guy to set it up for that, and since I've had no DTC's related to the O2 sensors, I assume it did as such. I assumed I'd be able to easily do the same in the 0411 PCM with tunerpro, but haven't found a way to. Thus my question, has anyone done this before with a 5.7L tune, or know how accomplish it? The closest I've found is a guy who used TunerCat OBD2 to modify a 5.0 to run with the dual cats, so same thing I'm trying to do, just opposite. In need of a 02 express van 5.0 and 4l60e 2wd stock file | GMT400 - The Ultimate 88-98 GM Truck Forum

A couple of ways I'm thinking I could make this work;

1-Just disable the DTC for the combined pre-Cat Sensor, which would be the post-Cat sensor in the 5.7 tune file. Bank2 Sensor2 I think. I can figure that one out.
2-Segment Swap the Engine Diag from a 2002 express Van bin file with the 5.0 (Should have the single exhaust, I think, its my understanding the 5.0 only ran one cat) Though I'm not sure what else would change in that segment for the 5.0 to the 5.7. And I've been unable to find a 5.0 Bin file either.

Any help on this would be greatly appreciated.

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Originally Posted by Themerlen

So new to this forum, so Hi everyone. I thought I'd be able to do everything I needed without having to ask a question, but I'm a little stumped on this one.

I have a 5.7L L31 Engine with a 4L60E sitting in a jeep, currently running off of the Blackbox PCM, I had the guy over at LT1Swap do the PCM, and it works great. But my intent is do the 0411 swap, I want to mostly be able to make changes on it myself using tunerpro, mostly gear changes, and tire changes to start with.

So in getting everything ready for this swap, I've already gotten the PCM to program properly, so no issues there. I'm working on the adjustments to the 2002 Express Van Bin file that's commonly used for this kind of swap. However, that Bin file is set up for dual exhaust with two Cats, and it was not practical to install two cats in my 89 Jeep. So I installed single exhaust with one cat, and asked the LT1swap guy to set it up for that, and since I've had no DTC's related to the O2 sensors, I assume it did as such. I assumed I'd be able to easily do the same in the 0411 PCM with tunerpro, but haven't found a way to. Thus my question, has anyone done this before with a 5.7L tune, or know how accomplish it? The closest I've found is a guy who used TunerCat OBD2 to modify a 5.0 to run with the dual cats, so same thing I'm trying to do, just opposite. In need of a 02 express van 5.0 and 4l60e 2wd stock file | GMT400 - The Ultimate 88-98 GM Truck Forum

A couple of ways I'm thinking I could make this work;

1-Just disable the DTC for the combined pre-Cat Sensor, which would be the post-Cat sensor in the 5.7 tune file. Bank2 Sensor2 I think. I can figure that one out.
2-Segment Swap the Engine Diag from a 2002 express Van bin file with the 5.0 (Should have the single exhaust, I think, its my understanding the 5.0 only ran one cat) Though I'm not sure what else would change in that segment for the 5.0 to the 5.7. And I've been unable to find a 5.0 Bin file either.

Any help on this would be greatly appreciated.

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Not completely sure what you want to do or asking but dual vs single cat systems only differ with the after cat sensor or sensors that monitor cat/cats efficiency. Neither have anything to do with engine operation. Both would still use 2 pre cat sensors. You could just disable the after cat/cats O2s and it would be fine. You just wouldn't have any catalyst monitoring should a cat go bad.

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Originally Posted by 2xls1

Not completely sure what you want to do or asking but dual vs single cat systems only differ with the after cat sensor or sensors that monitor cat/cats efficiency. Neither have anything to do with engine operation. Both would still use 2 pre cat sensors. You could just disable the after cat/cats O2s and it would be fine. You just wouldn't have any catalyst monitoring should a cat go bad.

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Incorrect, 3 upstreams on the factory single cat trucks. It very much does change how the engine runs.

GM has factory Express van tunes for L31s with a single cat as well as no cats and even no 02s at all. Some of the L31 calibrations are open loop only even.

Tunercats has the option to directly edit the Dual vs Single cat exhaust configuration, I made a dual cat 305 calibration when I put the L30 into my Tahoe and also made a single cat L31 calibration when I put a Mercruiser version of the HT383E into a 2005 Astro.

Factory exhaust and 02 configuration on a single catalyst Vortec. 3 pre-cat 02s. An 02 after each manifold and 1 after the Y-pipe. 1 behind the cat.

This exhaust matches the open loop only catless L31. My 2003 L31/5spd 4x4 GMT800 Sonora had the same type of setup but did use front 02s only. Factory EGR deleted, LS truck airbox and 85mm MAF on that one.

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Originally Posted by Fast355

Incorrect, 3 upstreams on the factory single cat trucks. It very much does change how the engine runs.

GM has factory Express van tunes for L31s with a single cat as well as no cats and even no 02s at all. Some of the L31 calibrations are open loop only even.

Tunercats has the option to directly edit the Dual vs Single cat exhaust configuration, I made a dual cat 305 calibration when I put the L30 into my Tahoe and also made a single cat L31 calibration when I put a Mercruiser version of the HT383E into a 2005 Astro.

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This would be the setup that I have. You wouldn't still happen to have a .bin file for an single cat L31 you'd be willing share, or know where to find one. All the ones I've found so far are dual cat. But now that I know it exists, it might make it easier to find.

Upstream sensor, (pre-cat) on bank one is B1S1. Upstream sensor (pre-cat) bank two is B2S1. The typical configuration with two post cats are numbered B1S2 and B2S2. A simpler way to do what I think you want to do would be leave B1S1 and B2S1 alone and just delete the post cat (sensor 2) data from your existing tune.

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Originally Posted by MO LS Noobie

Upstream sensor, (pre-cat) on bank one is B1S1. Upstream sensor (pre-cat) bank two is B2S1. The typical configuration with two post cats are numbered B1S2 and B2S2. A simpler way to do what I think you want to do would be leave B1S1 and B2S1 alone and just delete the post cat (sensor 2) data from your existing tune.

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This is likely what I'll end up doing, at least to start, and if I can get a correct bin file like Fast mentioned above then I can switch gears towards that. I like to keep as much functional as possible, but sometimes it doesn't always work out that way, at least in the beginning, and was hopeful that others knew of a way other than just deleting what isn't working correctly.

That 3rd upstream is used only on the 96,97 5.0Ls. Tunercat only shows it in the DTC list for those years. It is B1S2. The 98-99 5.0L just use B1S1, B1S2 and B1S3. B1S3 is after cat. Those are the only ones in the DTC list for those years. If you are doing a 0411 swap you will be using a later year OS so you will only need B1S1 and B2S1 O2s.