Help! Motor In--Dead, No communication

[indiansprings]

Thanks for all the help! It turned out to be the ground on the passenger side not being grounded to the block in the proper location. My son had grounded it to a stud on the valve cover. This created a 12.5 volt back feed on the ground. Once the ground was properly located it started and ran. The computer I had the local parts store order by VIN and engine info did not regonize the wireless throttle set up. I stuck the original 6.0 computer that a local shop assured me that was fried back in the truck and it has worked flawlessly ever since.

I have not noticed any issue with the 6.0 cmptr running the 5.3, idle is good, throttle pickup is good, runs out perfectly.
This truck being a 3500 4wd with a 4:10 ratio, I thought it might be a little under powered, but it seems plenty waspy for a farm truck.

I hats off to those that have answered all our questions. Being close to fifty and not the most cmptr/electronic literate guy it seemed a little overwhelming compared to the old sbc, but after getting this one done it really might be a little easier in the future.

I tore down the old 6.0 with my youngest son. It was a mess internally, two broke rods, one punched a nickle size hole in the block. Amazingly this truck would start and run with the two broke rods, it would just shake you out of the cab lol.

I bought the truck out of a salvage pool for 2400.00, the 5.3 I gave 450.00 for and have 400.00 in a hood and grill.
So for less than 3500.00 I have a 2003 K3500 4wd with a 5.3 with approx 4000 miles. The whole truck had less than 80K miles on it.

We put a 9' flat bed on it with a 6 ton hoist run by electric/hydraulic pump which we already had off another old truck ready for the crusher. It has turned out to be a very nice looking, excellent performing truck for the money.

Again thanks to ls1trucks site and its members for helping it be a sucessful project.

[banker099]

glad you got it going!!