Bowtie70SS, I think he was saying that he fixed his post. It didnt have his location and he was asking for local help to look at the truck. I think the 408 is still down.

 

Yes its still down and Im still not getting any throttle input. I can not get rid of this damn reduced power and that means I can not keep it runnning for longer then 15 seconds it just dies out.

 

Is the PCM still loaded with the 6L tune?

The only time I ever saw reduced engine power (light on the dash) was when I installed my Powerdyne and the PCM saw too much air coming into the TB and couldn't compensate so it just reduced power. After I turned the truck off for about 15 seconds then back on it ran fine, unless I went above 3500rpms then it reduced power again. Could your PCM be seeing too much air because of the extra cubes? Enough to confuse the PCM into reducing power?

 

I have no idea as to what is going on with this damn thing! Im sick of the entire truck at this point. BTW it has a 408 tune on it.

 

If the electrical connections checked out, I'd have the tune looked at again (for reassurance).

 

I tried to load a stock 6.0L tune also to see if the tune was the problem and I was seeing the same thing.

 

Is the 'Cylincder Volume' accurate for wht you have? I'm taking shots in the dark here, but the following parameters will need to be changed:

* Cylinder Volume
* Airflow Parameters (Base & Others)
* VE
...just to name a few of the major adjustments


I cannot remember if you stated you had tuning software or not, but I'd look into the tune if the wiring & airflow-related (IAC, MAF, TAC) check out. Now... not to insult intelligence, but... I recently swapped my cam, and thought everything was connected as should. I got the 'reduced power' symptom (no MIL display to show in my OBS RCSB), and went to the engine bay to find the pass-side main coil pack connecter was disconnected. Not saying that this is your issue, but sometimes the simplest things can be overlooked. If all connections check out, look into the tune. You should be able to start to idle, or at least two-foot until a Crank Learn can be done.

Just my

 

Did you check all the wiring? It is extremely easy to break and/or crush wires when swapping an engine, and it may be inside a loom where you can't see it.

 

When I tune mine with LS1-edit thru the obd2 port it also throws reduced engine power at me. I have to leave the ignition on , pull the cover of the fuse box under the hood and pull the PCM 1 and PCM B fuse, turn the ignition off, then put the fuses back in and start the truck and it goes away. I don't know if its something this simple but hope it helps.

 

worth a shot right.