PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

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Old Dec 18, 2013 | 07:16 AM
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Im at my wits end and need a fresh set of eyes/ears. Story, 03 Silverado, LQ4/4L80e. My cousins truck, he blew a head gasket a year ago, let it sit, and now I have replaced the engine with one from LKQ.

Everything is in, the engine spins over freely and seems to be in good shape. 54 psi of fuel pressure while cranking (after replacing the fuel pump), have spark, have air (obviously). No DTC's, but thats not all that telling with a complete re-boot I guess. It has injector pulse, 4.8v at key on, switching from 1.8-2.0v to 5.5v while turning engine over. It is also logging 150-190rpm while cranking. I guess a compression test might be in order now...

I'm inclined to believe its something with the VATS/security system, but the security light on the dash comes on at key on and then goes off about the same time the fuel pump has pressurized the lines. He does not have the original key or key fob either. The oil pressure gauge and trans temp gauge on the cluster are also both pegged to the max. I assume this is just the gauges. Can you log the oil pressure in the trucks? Or is it like Fbody's? Anyone have a pid for engine/trans oil pressure/temp? The security system does cut fuel correct? So the injector pulsing eliminates that theory?


I have tried cranking it without the MAF/MAP hooked up. MAP reads 99kpa so I assume its all sealed up. Would an 03 LQ4 have been a 24X? The replacement is an 05 58X. TIA for any insight
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Old Dec 18, 2013 | 09:34 AM
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Yes 03it is 24the tooth reluctor wheel. You will need an adapter. I am almost positive, but you can search that and get reaults.
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Old Dec 18, 2013 | 10:54 AM
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After a quick search on that, every LQ4 is 24x, from 03-07.
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