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LS3 won't start

Old 04-04-2012, 04:47 PM
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Default LS3 won't start

I have LS3 crate engine with GMPP controller kit that wont start.
I have a fuel pressure thats 54psi...I know it's a little bit low but should it start or not with what fuel pressure?

When I try to start it stumbles for three seconds and then it's like the ignition or fuel is completely cut of. If I don't remove the positive cable from the battery and wait for minute the ECM wont turn on the ignition or fuel again.
If the crank sensor is bad but the cam sensor is working will HP Tuners still show RPM?

I get the following codes from HP Tuners:

[] P0010 - A Camshaft Position Actuator Circuit (Bank 1) (Old) (Current) (Immature)
[] P0036 - HO2S Heater Control Circuit Bank 1 Sensor 2 (Old) (Current) (Immature)
[] P0056 - HO2S Heater Circuit Bank 2 Sensor 2 (Old) (Current) (Immature)
[] P0315 - Crankshaft Position System Variation Not Learned (SES) (Pending) (Old) (History) (Current) (Immature)
[] P0452 - Fuel Tank Pressure Sensor Circuit Low Voltage (Old) (Current) (Immature)
[] P0463 - Fuel Level Sensor Circuit High Voltage (Old) (Current) (Immature)
[] P0807 - Clutch Position Sensor Circuit Low (Old) (Current) (Immature)
[] P2078 - Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit High (Old) (Current) (Immature)
[] P0315 - Crankshaft Position System Variation Not Learned

What should I do?
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Old 04-04-2012, 08:56 PM
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I believe there is a crank relearn procedure that you do with a scanner. I don't remember if it will keep it from running. But basically you have to start that and then usually you have to run it at 3grand for a few seconds.
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Old 04-05-2012, 05:48 AM
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Did you disable VATS?
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Old 04-05-2012, 05:50 AM
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Didn't see you had controller kit. Nevermind.
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Old 04-05-2012, 07:55 AM
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Does your switched power source have power when the key is in the 'CRANKING' position?


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Old 04-05-2012, 09:42 AM
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Are all your grounds well connected? As well as the body of the ECU grounded?
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Old 04-05-2012, 10:59 AM
Staging Lane
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ECU body is not grounded, i'll try that on sunday.
All other grounds are connected to the block and heads.

The switched power source is connected directly to the battery.

All ideas and thougts are welcomed!


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Old 04-05-2012, 11:29 AM
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Your switched PCM wire needs to be connected to a switched power source that has power when in the cranking position, it can't be connected to the battery and powered at all times.
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Old 04-05-2012, 11:34 AM
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Also, your engine needs to be grounded to the frame. These engines need to be grounded lots, the ECMs like it.

I got ground strap from the back of the block to the body, front of the head to the frame or the battery negative, I cant remember right now and its a BLIZZARD outside today and I cant find my cars.
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Old 05-08-2016, 03:06 PM
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Default ls3 wont run

I have almost the same error codes and won't run, did you get it to run and what was the problem? Thanks
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Old 05-08-2016, 04:47 PM
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It may sound silly, but are you sure you got the MAF in the air intake tube and connected to the ECU harness correctly?, if I get the MAF disconnected or not inserted in its slot the engine would run for a second or two and then will die.
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