Hey everybody NEW KID ON THE BLOCK HERE

[jjohnson]

Hey everybody my name is Jake and I am fairly new to working on trucks or any vehicle for that matter. I tend to be a guy that's a bit impulsive and tends to jump right into things, sometimes without knowing very much about what I am doing. I just came from Full Size Chevy with my current situation and everybody told me how knowledgable you guys are at LS1 Truck and how I should post my thread over here.
I just finished switching my 2004 4.3 v6 with a 2003 4.8 v8. The physical conversion was flawless. Motor mounts were the same and driveshaft was the same length also. Along with the v8 motor, I used it's transmission, transfer case, brain, motor harness, fuse box, fuel lines, air box, radiator, fuel pump along with the electronic throttle setup that replaced the existing throttle cable setup; which simply included the pedal, 1 pigtail harness to the throttle control module, which the motor harness plugged into the other end. Every wire connection went together no problem. Note: I did not change the in dash harness. Every conceivable option that I had in the truck seems to be working properly, including the turn signals, all lights, dash cluster lights, radio etc... The only problem I am having is that the vehicle won't turn over or fire up. The fuel pump won't even engage. I'm pretty sure that all my connections are plugged in. Note: all components worked before conversion took place. At first I thought It might be in theftlock mode, so I attempted to do a relearn procedure to fix the situation but the theft light disapears with the rest of the cluster lights after attempting to start vehicle exept the check engine light. The check engine light stays on. Also the dash digitally says: Service brake booster. And there you have it. I was really hoping that someone might be able to critique what I have done, and possibly point out something that I might have missed or overlooked. Any suggestions or thoughts will be much appreciated.

[RedHeartbeat]

Did you have the VATS turned off inside the PCM? That is a must.

[jjohnson]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Mar 31 2006, 10&#58;53 AM) [snapback]48865[/snapback]</div>

Did you have the VATS turned off inside the PCM? That is a must.
[/b]

Could you explain a little more about the VATS and how you would turn it off. Are you simply referring to the passlock vehicle theft deterrent system

[RedHeartbeat]

That is the Vehicle Anti-Theft System inside the PCM logic. The PCM expects the Body Control Module to send a signal to it showing that the correct security diode resides within the key in the ignition. PCMs require different values and if the correct one is not there you don&#39;t get the authority to start the engine, turn the starter or signal the fuel pump. Damn good security measure, huh.

[jjohnson]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Mar 31 2006, 11&#58;03 AM) [snapback]48867[/snapback]</div>

That is the Vehicle Anti-Theft System inside the PCM logic. The PCM expects the Body Control Module to send a signal to it showing that the correct security diode resides within the key in the ignition. PCMs require different values and if the correct one is not there you don&#39;t get the authority to start the engine, turn the starter or signal the fuel pump. Damn good security measure, huh.
[/b]

Yeah i&#39;d say&#33; How does one go about changing the PCM logic to match the BCM

[RedHeartbeat]

You&#39;d probably have to find someone with a TechII to reprogram the BCM and PCM to match each other and your current key chip. The simplest way is to have someone turn off the VATS in the PCM using HPTuner or a PCM programming software like it. Allen Nelson at www.NelsonPerformance.com can do that for you or you could just have him burn you a custom performance PCM to up the HP level while he&#39;s at it.

I forgot to ask, you do have a fully charged battery, transmission selector set in Park or Neutral? No blown fuses? Power to all the fuses? A good ground cable on the engine?

[jjohnson]

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Mar 31 2006, 11&#58;13 AM) [snapback]48870[/snapback]</div>

You&#39;d probably have to find someone with a TechII to reprogram the BCM and PCM to match each other and your current key chip. The simplest way is to have someone turn off the VATS in the PCM using HPTuner or a PCM programming software like it. Allen Nelson at www.NelsonPerformance.com can do that for you or you could just have him burn you a custom performance PCM to up the HP level while he&#39;s at it.
[/b]

When you say reprogram, is that the same as reflashing your pcm? Are the dealers the only ones with a tech II tool? Also would there be any problems with my PCM and BCM being programmed together do to the fact that they both have different VIN numbers stored in them? The PCM is from the v8 and the BCM is from the the v6.

[RedHeartbeat]

That&#39;s a grey area to me. I run a 98 T/A LS1 in my 93 C1500 and had to disable the VATS to get it to start. There might be someone more knowledgable about the 2004/2003 swap you did than myself. I know what I have read in the past about the VATS and BCM compatibility. They must talk to one another without flaws. The PCM may have to be upgraded to a 2004 flash to talk to the 2004 BCM.

More than just dealers have the TechII but they are very pricey, about &#036;5000.

[jjohnson]

Thanks alot for all your help redheartbeat, I really appreciate it. Is there anybody else out there that could give me some advice on my swap?

What do you guys think I sould do. Should I post this thread in a different category? Do you think that I might get more feedback? If so, which one should I post it in?

[RedHeartbeat]

Give it 24 hours at least. We&#39;re not as big as PT.net but we&#39;ll get around to you.