5.3 help

[beto101]

Ok finally got my 5.3 in my blazer.
Got it to start up but cant get it to stay on. Idles rough for a while then shuts off. Any ideas?

 

[Hogback Fabrication]

Did you setup a check engine light system?

If so, what codes?

If not, you need to do that...

 

[DeviousK5]

Could be idle re-learn . Hook up a battery charger to the system, on trickle with the key on . Let it sit for about 10 min. start it up see if any better. All gen3 engines have a time and a half idling after battery disconnect.

 

[buefchris]

Most ls ecm's have built-in securities that shuts off the engine.
After a few times, it won't run at all until it's cleared.

 

[noJeepshere]

Someone wrote a tech article on this very subject (5.3 swap) You could look it up and see what he has to say about it.

 

[k20]

Probably the VATS system kicking in. I just bought a wrecked 04 2500hd from my work, swapping the 6.0/4l85e into the gf's 89 c2500, reading and learning that I will either have to buy a tuner (efi live, hptuner, etc) or send off the pcm to be reprogrammed to turn the VATS off. The guys over on ls1truck all recommend this guy http://www.nelsonperformance.com/tuning.htm