LS swap starts and dies

[Fastmike91]

Hey everyone, we've got a 66 c10 in at work that someone has swapped an 08 5.3 out of a Silverado into. I believe its a PSI harness. The harness was already in the truck when it came in. We just finished wiring the body and attempted firing the truck for the first time. It's a stock engine minus headers and a intake tube to be able to fit in the truck. I disabled VATS and that is all so far but the truck will fire and up and die in about 3 seconds. It acts just like vats. We have good spark and fuel injector spray. I back probed and checked the cam sensor and everything checks out. Sometimes it will just crank and backfire out of the exhaust as well. I also checked wiring at the MAF and MAP sensors and it all checks out. I'm not sure exactly where to go at this point so any help would be appreciated!

[Alvin]

In System - General Change starter relay diag to disable.

You did do a WRITE ENTIRE right? You need to do to turn off vats.

You also have a cam position sensor code which at a minimum would make every other start hard. (engine won't know which TDC its on) but I have run into GMPP setups that flat out will not run with a cam sensor code present. You'll need to fix it anyway, I'd suggest looking into that code.

[Fastmike91]

I saw the cam sensor code and tested the sensor and it checked out ok but I have one from the parts store on the way. It makes sense because it randomly will backfire like its out of time.

I did write entire to disable VATS.

I will try the starter relay diag but even with it enabled it will sometimes start perfectly but shut off like VATS is still enabled.

Thanks for responding!

[5FDP]

Why did you apply the 2 bar OS to this file? Are you running boost?

The 2 bar OS creates 3 new VE tables and removes the VVE tables found under the edit tab. Those tables when created have ZERO data in them, so with no fuel (data), it will not want to run.

[Alvin]

Why did you apply the 2 bar OS to this file? Are you running boost?

The 2 bar OS creates 3 new VE tables and removes the VVE tables found under the edit tab. Those tables when created have ZERO data in them, so with no fuel (data), it will not want to run.

Wow good catch!

yeah your VE is all 0's right now. It would be easier not using a 2 bar OS to get going for sure.

[Fastmike91]

That's interesting! I don't know if someone has been in this ECU before. It was already in the truck when it came in. I actually don't even know if its from the the truck the engine came out of. How do I remove the 2 bar os so my VE tables are populated again? No boost on this truck. I'm fairly certain its a bone stock 5.3 as it doesn't look like its been taken apart before.

[Fastmike91]

Paul Scranton 1966 C10 no VATS.hpt

[Alvin]

that one doesn't have a 2 bar OS. I'll bet it will run

[Fastmike91]

Still fighting the same issue.. It's acting like VATS is enabled but it's not.

[chaos4life]

Still fighting the same issue.. It's acting like VATS is enabled but it's not.

Did you ever find a solution? Im having the same exact issue with a 4.8 ls swap in a 78 cj7. Itll run for a second then die like VATS is still on. Turn the key over again and it will either 1 fire back up and die or 2 it will backfire out the exhaust.

[blindsquirrel]

backfire out the exhaust.

Cam sensor. (that doesn't mean 'you need to replace the cam sensor')

[blindsquirrel]

Did you ever find a solution? Im having the same exact issue with a 4.8 ls swap in a 78 cj7. Itll run for a second then die like VATS is still on. Turn the key over again and it will either 1 fire back up and die or 2 it will backfire out the exhaust.

If you read the whole thread, and you do indeed have 'the same problem', does your file that you neglected to post also have a 2-bar OS applied without all of the changes needed to make it work, like the other guy's problem was? Or did you only read enough to see something that sounded like your problem and thought 'oh I know, I will ask here'?

[pannetron]

blindsquirrel, I like your style!

[chaos4life]

If you read the whole thread, and you do indeed have 'the same problem', does your file that you neglected to post also have a 2-bar OS applied without all of the changes needed to make it work, like the other guy's problem was? Or did you only read enough to see something that sounded like your problem and thought 'oh I know, I will ask here'?

Well Sir ill ask you the same question did you read the whole thread? The OP clearly stats that the OS change made no difference in his problem nor did it provide a solution. So ill ask again what was the solution and why? Reason for asking is im having the same exact issue all the way down to the cam position error code. I like OP changed sensor and still same result. As far as posting a file for you to look at and give the same answers that have already been givin seems pointless when there is no solution. Now hopefully that makes sense to why i asked here. Could have wasted time starting a new thread but hell this one never got finished.

[chaos4life]

was it the sensor itself or wiring issue? Or did you just give a generic answer?

[chaos4life]

blindsquirrel, I like your style!

blind leading the blind. Lol

[blindsquirrel]

The OP had a tune file with a VE table filled with all zeroes, and said he had no idea how or when the custom OS got applied, which means it probably was not flashed right the first time since it takes a very specific set of steps to do that, and those wouldn't have been done if the OS got applied by accident. I am sorry that you did not understand all that, but now you do. Right?

So if you did not also have a file that accidentally got a COS applied and has a VE table with all zeroes and then flashed it to the ECM wrong, then you do not 'also have the same problem'.

[chaos4life]

The OP had a tune file with a VE table filled with all zeroes, and said he had no idea how or when the custom OS got applied, which means it probably was not flashed right the first time since it takes a very specific set of steps to do that, and those wouldn't have been done if the OS got applied by accident. I am sorry that you did not understand all that, but now you do. Right?

So if you did not also have a file that accidentally got a COS applied and has a VE table with all zeroes and then flashed it to the ECM wrong, then you do not 'also have the same problem'.

And im sorry you still dont understand that the OS file change did not fix the problem. and after that i do have the same issues as described by op. Understand? What was the solution or is it still sitting in the back corner of a shop somewhere?

[edcmat-l1]

And im sorry you still dont understand that the OS file change did not fix the problem. and after that i do have the same issues as described by op. Understand? What was the solution or is it still sitting in the back corner of a shop somewhere?

Why don't you do what normal people do and start your own thread? Post your vehicle specs/mods, tune file and data log.

There are many of reasons for "My LS swap starts and stalls". Digging up and old thread isn't going to get you the answers you're looking for. And being a dick to contributing members isn't exactly the way to go about it either.

[LS ROB]

And.. here.. we.. go! Aww man, no popcorn!