The 6 liter just screwed me for the first time this year......

[sman]

Car will not start, fuel pump runs, sounds like it usually does, cant be more than 30k on it.

Car cranks and fires and misses/stumbles and dies, I can feather the gas and keep it running 3 seconds if im lucky.

I know the crank sensor is good, as the tach is reading fine, this was already replaced 2 years ago for very similar behavior.

No pending or current codes.

Everything up front, tps, maf, ait, idle air, etc are all connected. Car was warm.

Im not happy at all, any easy to check ideas? Its at the house (stuck half way down the drive way blocking everyone in) not at the shop so I have basically ZERO tools....

Weve got fuel, air, and some spark apparently. Wtf am I missing, I know this car in and out just cannot think of whats holding me up here.

[shawnc16]

Replace a known good cam sensor?

[Emulsifide]

Can you check fuel pressure? Do you have an aftermarket pump? I'm thinking the bendy straw like tube going from the pump to the pump assembly might have popped loose. Just food for thought. I hope you get it figured out.

[sman]

Cant check fuel pressure, dont have a gauge. Really dont want to start throwing parts at it for no reason, not made of that kinda cash.

Fuel pump is a new ac delco unit put in like 2 or 3 years ago through the bottom.

[1BADAIR]

car will run without a cam sensor. will have long crank.
fuel or vats

[my95z28]

car will run without a cam sensor. will have long crank.
fuel or vats

I thought vats wouldn't let the car crank?

[sman]

Vats was disabled when I bought the car, never had a problem with it, security light is not on.

[Emulsifide]

Two things to check regarding fuel.

Grab a coolwhip container or something of that sort, disconnect the fuel line from the rail and have someone hold it over the container while you turn the ignition to on. Watch the flow, as it should pour out at a decent rate.

It could also be a blocked fuel filter.

[Emulsifide]

I thought vats wouldn't let the car crank?

VATS won't let the car crank, so it's definitely not that.

[1BADAIR]

there are diff parts of vats. one section will even allow the car to be driven under 5mph or so even when enabled.
is anything losing power when you release crank? if so the ign switch could be an issue. LOL this is a big pain when putting ls1 in fords.

[nascarnate326]

You guys may want to recheck your VATS facts.

Different versions of VATS do different things.

If it starts for 3 seconds than the BCM is getting the key OK signal from the keyswitch, but the PCM is shutting down the injectors. My old grand am had that situation.
My camaro on the other, the BCM would not ground out the theft deterrent relay to engage the starter.

Not saying that VATS is the problem, just dont count it out. IMO I would get a 50 htz box and bypass VATS, ground out the ignition relay so you KNOW that VATS isnt the issue. Took me two months to realize that with that box and 25 min work my problems went away.


Do you know if your security light is working properly? Is your BCM good?

[sman]

Security light comes on when the cluster flashes the rest of the lights, I dont think its vats, I bought it with it disabled, ive seen the wiring under the dash to prove it. Its not like it runs good for 3 seconds and dies, it is a MASSIVE struggle to get it going and it just kinda fizzles out, not like the computer just killed the fuel or spark. Like im cranking 5 to 10 seconds and feathering the gas even to get the rpms above 500. Runs like its on 4 or so cylinders and shakes violently and thats it. Ill get a video tomorrow.

[Fox Slaughter]

Well use a test light or feel to see if the injectors are firing.

[c0ncEpT]

Are your drivers/passenger coil packs unplugged?

Even a cammed LS1 will run on 4 cylinders. Not well but they will run

[sman]

Checked that, I know it will run fine on 4, even 3. When I first put the 5.3 together a few years ago I couldnt get the pass side going till I did some rewiring. It ran just fine, even drove it to the exhaust shop on 4, lol.

Thats not the issue hear however. Ill have to see if I can borrow a noid light to test the injector wiring tomorrow, all ive got are test lights.