Tryhard

Info needed to help me diag. this issues.
Problem 1: Hits(fires up) and instantly dies.

what I have done so far:
--fuel pressure is at 55psi key on. cranking is the same.
--confirmed injectors are working
--spark on all 8
--new plugs/wires
--new maf
--no 02's at the moment as there is no exhaust on yet
--ecu, based off vin, is a 02' half ton chevy 1500 4x4 with 5.3 motor.
--wont even stay running with starting fluid.
--reset ecu manyyyyyyyyyyyyy times.

What I have in parts:
--stock 5.3 with 6.0 317 heads
--stock truck intake
--ls9 headgaskets
--psi wiring harness
--rewired trans connector for 4l80e per psi's wiring instructions.(only switch two wires, s and u terminal)
--only sensor not hooked up is oil pressure

Now, from what I've been reading there is something about VATS. Considering there's no bcm in the car, would that prevent the motor from running? Cause it fires and hits ONCE and dies. I figured VATS wouldn't even allow spark. Since there are no 02 sensors, they wouldn't prevent the car from running. May run like ****....but it will run.

My hand held code reader from matco is pulling a p0452 evap code. and of course the sensor is on top of the intake which there isn't no wires or hose to it. I can see all engine data as well. Confirmed map sensor is good. 3.0hz unplugged and 29.2hz plugged in. Checked for power and grounds all over. Kinda wondering if I need more grounds. Only one I have is battery to finder and battery to right side head of motor. Also the wire on the alternator that goes to the battery is UNHOOKED. I ran out of wiring and have yet to do that.

Well, that's what I got and I really don't know what to do next. I need help on this one.

Thanks,
Dave

Tryhard

been reading and found this.
https://ls1tech.com/forums/pcm-diagn...-no-start.html

kinda the same issues. hits and then dies. I have a 4l60e crank sensor as the motor came with the 4l60, however i placed in the 4l80 and flywheel with spacer. I wonder if the ecu is seeing crank signal after the hit?

Prorac1

iTrader: (4)

I don't believe theres a difference between crank sensors with the 4L60 vs 4L80. Just with the 24x reluctor and the 52x reluctor. IIRC, the 24x sensor is black, and the 52x sensor is gray. Eric L

Tryhard

"swing an a miss...batter out''

Well, ****. Back to square 1.

Another post I found was a guy said VATS will allow the motor to start for 1 sec, and when it dont meet the requirements needed it shuts the injectors off. I havent stuck a Noid Light in the injectors to see what happens yet, but I'm 90% sure its ecu related problem.

Prorac1

iTrader: (4)

You have to tune VATS out. If you haven't done so, than that's probably the problem. Eric L

fire67bird

Yes you are correct that you need to disable the VATS. I would stop all diagnosis/modification until you get this done or confirmed that they are already disabled.

408-99-f

I agree its the vats. I read somewhere GM claimed that they had complaints about cars having extended crank times. So they set it up to fire first. Then run the security check. If you can get your hands on a good scan tool it will tell you if it is shutting down because of this. I have a OTC genesis and it has it. Any upper level tool.

CattleAc

iTrader: (7)

VAT's has to be disabled before it will stay running...

Tryhard

NEXT STEP= VATS REMOVEAL.

As soon as its done i'll post results for future research.

Prorac1

iTrader: (4)

They can also disable the evap code as well. Any good tuner knows the basic codes to disable for a swap vehicle. Best of luck. Eric L

Old Geezer

iTrader: (3)

if there's fuel psi, and then it fires and dies instantly, and won't run on st fluid, it may be you don't have coil/ign power in the run position. [It dies as soon as you release the key??]
VATS will usually allow some several seconds of run time B4 shutting down.

Tryhard

I have the psi's wiring harness on there. If you are correct, what do I check as the harness only has 2 grounds and 2 power wires to hook up. Power wires are on starter which is to the battery. One ground on rear left cylinder head, other ground (near fuse box) is on the floor of the car. I have checked coils and main coil connector. Both are showing 12v after it dies. Injectors show 12v as well. But they fire through the ground wires.

Tryhard

Just took my power probe and checked at injector 1. Has 12v and when the car cranked and fired, the ground wire flashed one time. The ecu is killing injectors. Has to be vats.

71ANTICARB

iTrader: (23)

Vats.

Prorac1

iTrader: (4)

If you don't have a BCM, than its imperative that VATS is tuned out. Eric L

Tryhard

VATS turned off with hpt and she started and runs. Sounds so good. Now off to the body shop to finish body and paint.

Thank you everyone who helped with my issue. Nothing beats experience!!!!!

Prorac1

iTrader: (4)

Glad to help. Good luck with the rest of the project. Eric L