Conversions & Swaps LSX Engines in Non-LSX Vehicles
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Old Aug 14, 2016 | 10:55 AM
  #1  
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This is my first LS swap. 2002 5.3 and 4L60E going in to a 1987 GMC SWB. The truck originally was a TBI truck from the factoru with dual tanks with in tank pumps. I have switched the pumps pver to the AC Delco EP-381.

Morning frustration update:

I was given the attached list with my harness. So far, all i have hooked up is the re, white and blue wires at the top of that list.
I have the red going to battery, the white going to large pink on left hand side of bulkhead and the blue going to the tan/white on the left hand side of bulkhead as well. I have not hooked up any of the other wires on the bottom portion of his list.

I am getting power to fuel pump relay when key is turned on. Also the tan/white wire goes hot at the same time. But, i am not getting any power to the fuel pumps. The tan white goes to the tank selector valve and then terminates. So how do i then get power to gray wires on sending units to power the pump? This was a running truck with no issues a month-and-a-half ago and the selector valve is brand new.

Truck fires and instantly dies. I took the fuel line off at the fuel rail and there is plenty of fuel and pressure getting to the fuel rail.

Thinking the ECM was not flashed properly and the VAT's are the problem but who know. Need someone in the DFW who can flash/tune the ECM.

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Old Aug 15, 2016 | 03:36 PM
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You are contradicting yourself. You say you have no power to the fuel pumps yet you have fuel pressure? It's got to be one or the other. If you have fuel pressure then you've got to have power to the pumps to give you that pressure. If the motor starts and dies it is probably vats.
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Old Aug 15, 2016 | 10:51 PM
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Maybe the fuel pump is getting the 2 sec prime signal, but not the run signal. Not sure what triggers that, maybe the CKP?
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