LS3 is in but I have a no start issue...

Swapped out the LS2 for the LS3 and it is all hooked up. Not getting spark or fuel, but I do have fuel pressure. No coded are being thrown. Any ideas?

VATS disabled?

Yes vats is disabled.

What computer are you using and what reluctor wheel is it programmed for (24t or 58t). As well, I believe there was a change between ls1/2 and ls3 cam sensor wiring where pin A and C need reversed. Check schematics to be sure. Also check the crank sensor wiring as well.

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This large ground wire comes off of the battery and they have it connected to the back of the motor with a few other grounds. I was thinking it should be connected to the chassis? Its the one that looks like its wrapped in electrical tape.


Cam sensor and crank sensor are ls2.  Reluctor is 24x.  So you are saying I need to re wire a&c with this config? Wouldn't it at least sputter if the cam sensor was off?  And wouldn't I get a code? I've got no codes and the HP tuners is showing no rpm. So we know it isn't showing the crank sensor. That's why I'm thinking it may be a ground.

zeusrotty wrote:
This large ground wire comes off of the battery and they have it connected to the back of the motor with a few other grounds. I was thinking it should be connected to the chassis? Its the one that looks like its wrapped in electrical tape.

Cam sensor and crank sensor are ls2.  Reluctor is 24x.  So you are saying I need to re wire a&c with this config? Wouldn't it at least sputter if the cam sensor was off?  And wouldn't I get a code? I've got no codes and the HP tuners is showing no rpm. So we know it isn't showing the crank sensor. That's why I'm thinking it may be a ground.

There should be a ground wire from the battery to the inside of the firewall and then another off that point through the firewall and to the engine as shown.

If the computer is 24t, the reluctor wheel at the crank needs to be 24t. If not, the computer wont know where the crank is in its rotation. As far as I know, all LS3 engines had the 58t wheel. With a 24t computer and a 58t reluctor wheel, I doubt the computer will send any firing signal to the injectors for fail of an idea of which one to fire.

The motor does have a ls2 crank and 24x reluctor wheel. all sensors are ls2. Computer is 24x also.

Ah okay. Caught up. After checking grounds on block and heads, if you have 12v at injectors and coils then yes, you need to confirm the connections at crank and cam sensors are tight and that the wiring is correct.

It's running! Apparently the guy that was working on it switched the crank sensor with the cam sensor. Switched them back and boom... She lives again!

Now we're just buttoning up a few things. I have Nick Williams throttle body that had the blades drilled for a different car, so now we have to figure out where that needs to be. Fans need to be wired, and a few little leaks here and there need to be tended to. Have to bleed the clutch, and get some freon in it. Haven't driven it for almost a year. I'm excited!!!!

Congrats!

Again great info here on troubleshoot fix ideas.

Makes me dream of the day i'll have my first start with my block in.