LS SWAP Help...AGAIN

[JJAB]

I have everything in place... Rebuilt 6.0/4L80E, harness and computer rewired and calibrated by Todd in Arkansas. Here is my problem:

When I go to start the truck, it catches and cranks for a second and the dies. I have not had a lot of time to do other tests and diagnostics because of work. I just thought I would get some ideas of what you guys think it is.

[usmcchevy]

Almost sounds like VATS is not disabled in the PCM.

[BR3W CITY]

x2 sounds like vats. I'm not sure who Todd in Arkansas is but I would make sure he disabled it.

[ls1nova71]

X3

[JJAB]

Does anyone have list of PCM tuners in Texas. That is where I am located and I would like to get my pcm looked at ASAP.

Also, will the pcm give me a code if I do a code check to tell me if VATS is causing it not to start?

[JJAB]

Is there another way to disable the VATS other than sending it back to the tuner.

I used a guy named Todd of Powers Performance in Arkansas. Off course, with today being Good Friday, I am not getting an answer.

[BR3W CITY]

I've seen a couple threads on building a bypass module, but the time and effort involved make it less appealing

[Clyde65]

There is Nelson Performance in San Antonio. not cheap but they send you a PCM, you return yours.

[JJAB]

I did speak to the guy who tuned my PCM. He explained to me that if the VATS were not disabled that it would actually crank and run for at least 5 to 10 seconds. He instructed me to double check my ground wires, and then check my fuel pressure. I am also going to try and pull a code to see what the PCM is telling me. Any suggestions are definately welcomed!!!

[sandking]

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[406 Q-ship]

If you don't have the oil pressure sensor hooked up the engine will fire and die after a few seconds. It is a saftey feature built into new cars/trucks so the idiots of the world cannot drive a vehicle with no oil pressure, then try to get it warrenteed. I didn't think the trucks have the VATS system, that is a Camaro/Corvette thing.

[ls1nova71]

Originally Posted by 406 Q-ship

If you don't have the oil pressure sensor hooked up the engine will fire and die after a few seconds. It is a saftey feature built into new cars/trucks so the idiots of the world cannot drive a vehicle with no oil pressure, then try to get it warrenteed. I didn't think the trucks have the VATS system, that is a Camaro/Corvette thing.

This is not true on any GM vehicle, can't say for sure about other brands/imports, but GM has never done this. The old TPI's had the fuel pump wired in series with the oil pressure sensor, but it was only a back up in case the fuel pump relay died, but wouldn't stop the engine from ever running if there was no oil pressure.

Trucks have VATS starting in 1999 I believe, and the ONLY way to bypass it is to have it tuned out. If you had a Camaro or Corvette LS1 up to about 2002, you could get or build a VATS bypass module, but it never works with the serial type VATS that the trucks have.

If the VATS is not disabled, it will usually just sputter and try to run and then die, but I've never seen one run 5 to 10 seconds.

Not trying to be a jerk/know it all or anything, just trying to keep the facts straight

[BR3W CITY]

^ This is true. I asked the guys at FIC about having to connect the Oil Pressure and Oil level wires, and was told they were not needed to make the truck run.