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Fuel delivery/pump issue

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Old December 4th, 2018, 3:48 PM
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Default Fuel delivery/pump issue

I’m finally getting around to trying to get my 05 trailblazer running again. Been working with a no fuel issue. It died when accelerating and wouldn’t restart. No fuel pressure so I put a new pump on it. It ran for about an hour (very rough) and then wouldn’t restart. Towed it home. Would restart but not stay running. Fuel pressure would be chaotic and vehicle would die after a few seconds. Eventually led to no start at all. I wasn’t getting 12v to prong 85 of the relay from pcm control. Changed the pcm with a preprogrammed pcm. I’m still not getting proper voltage to pcm control side of the fuel pump relay (85). I have already changed the fuel pump and the pcm. I have a good ground (86) at the relay and proper voltage thru the fuse beside it (prong30). Any ideas or suggestions?
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Old December 4th, 2018, 4:13 PM
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Did you swap the relay?
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Old December 4th, 2018, 4:52 PM
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Yes I have. I also tested continuity from the pcm control prong to the pcm and it is good.
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Old December 4th, 2018, 5:06 PM
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One thing to check from the list is, if you haven't clean the crap out of the relay base with contact or electrical cleaner.
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Old December 4th, 2018, 5:16 PM
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I have definitely cleaned all connections very well. What all scenarios are necessary to turn on the positive driver in the pcm?
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Old December 4th, 2018, 5:27 PM
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This is either on or off circuit. Re-cap, you've swapped relay, cleaned base, same issue, replaced pcm. Reading voltage at the relay, reading voltage at the pump, relay, with the same ground point? Swap either the horn or a/c relay with fuel pump relay just to totally (almost) rule that out as an issue.
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