mrfubs

so i rebuilt my 5.3 with a 222/230 596/600 111 lsa cam with ported heads, i just got the engine in yesterday with a built 4l65 and a 2300-2500 stall converter.


i went to take it for a short ride down the street and had to accelerate 2500+ rpms to get up to speed, thats the converter but about a half mile away the truck shut off with no noises or anything.
The AFR was 14.6 good as could be and the truck would not start back up. i disconnected the battery for 10 mins and bam fires up but wont run as long as it used too it keeps shutting off.

Im getting it tuned shortly but is this happening because the stock pcm doesnt like the cam one bit?

its a 2000 gmc sierra

Darkman

iTrader: (2)

Has it thrown any codes?

JustAFooL

iTrader: (45)

You didn't mess up your motor. It's obviously thrown a code or something. Get a tune, it'll be fine.

mrfubs

alright becuase the reason i was skeptical was i ran the motor for like 15 mins for no problem and drove it for 5 anyway i was also just told today that you should not bore these ls block more than .010 over because of thin walls? well mines .030 how dangerous is this?

snowman47

You can take some 5.3's out to a 4" bore. Which is like .220 over...

RezinTexas

yeah, 0.030 is nothing for a 5.3 block.

lmt0705

iTrader: (7)

Do You Have Some Loose Grounds To The Ignition? Specifically The Ground Wires Behind The Cylinder Head?

Streetlegal?

iTrader: (25)

I bet that's what it is. Mine did that when I put my motor back in because I forgot to tighten one of the head grounds. Check them and I bet one is loose.

jclayc

iTrader: (8)

mine did that when one of the wires to the starter shorted against the solenoid body

mrfubs

all the grounds are where they should be and tight i paid special attention to that, any way i uploaded a video of me trying to keep it running just so i can check for leaks. This thing should lope realllll nice once tuned

JoeyGC5

iTrader: (24)

Long term fuel trims reset and it was probably maxing out the LTFT's. Get it tuned and enjoy the drive.

iron block, if sonic tested, can be bored quite a bit. Aluminum LS1/2/3 blocks usually can only take 0.005-0.010 at the max.

rhino200099

iTrader: (1)

kinda sound like it.

mchicia1

iTrader: (5)

Man not trying to scare you, but you should never run a new engine untuned. The thing could be dumping fuel into the cylinders and washing your rings down which could cause them to never seat properly.

The first startup through the first 5 miles are the most critical part of a new engine break in.

mrfubs

hopefully its fine the AFR was at 14.6 whats the best way to break it in once its tuned? miles wise and throttle wise

dannyz

No washdown there with that afr.
I am on board with everyone else. Something very minor, more then likely a loose wire, is the culprit.

mrfubs

Heres a new vid of the 5.3 idling after half way tuned

mchicia1

iTrader: (5)

It was 14.6 because his 02 sensors were bringing him back to stoich because he was in closed loop. It doesn't mean the tune wasn't way off while the car was in open loop.

It's just a bad idea breaking in a motor until the tune is at least in the ballpark.

Anyway, use break in oil then moderate throttle up to like 3500-4000 rpms and then engine braking back down to about 2k, repeating that 10 or so times. Change oil after the first 50-100 miles. Put in some more break in oil and run it another 500-1000. Change to oil of choice or whatever the builder recommends.

There, the engine is broken in.

RAGaines3

Ground problem or fuel. My Z did that when the fuel pump started getting weak, then it left me stranded.