Wondering if anyone has a clue on this. I have a no start condition on the port 7.4 454 TBI fuel injected engine. Fuel pressure measures at zero just before the TBI injection assembly on the intake manifold.
I hear fuel pump prime on key turn. I measure 12V at key turn only for priming, then it goes to zero, when I turn key and cranks its dropping to 9V and is really erratic jumping up and down.
I cannot find a fuel pump relay on this engine to replace.
Pulling fuel pump off engine and connecting to 12V it runs fine and sounds strong with good suction (air) on fuel line intake port.
I was thinking this is an oil pressure switch issue but I've been told the XL, unlike the earlier 454 does not use oil pressure switch to allow power to the fuel pump. I still bought a new switch since its not terribly expensive for this model, unlike the earlier "pig tail" oil pressure sensors for Crusaders. Please correct me if I'm wrong.
Any clue why my voltage woudl fluctuate to the fuel pump. New fully charged batteries, but addmittidly the engine sounds weak and tired turning over.
I hear fuel pump prime on key turn. I measure 12V at key turn only for priming, then it goes to zero, when I turn key and cranks its dropping to 9V and is really erratic jumping up and down.
I cannot find a fuel pump relay on this engine to replace.
Pulling fuel pump off engine and connecting to 12V it runs fine and sounds strong with good suction (air) on fuel line intake port.
I was thinking this is an oil pressure switch issue but I've been told the XL, unlike the earlier 454 does not use oil pressure switch to allow power to the fuel pump. I still bought a new switch since its not terribly expensive for this model, unlike the earlier "pig tail" oil pressure sensors for Crusaders. Please correct me if I'm wrong.
Any clue why my voltage woudl fluctuate to the fuel pump. New fully charged batteries, but addmittidly the engine sounds weak and tired turning over.