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Discussion Starter · #1 ·
Does the 1989 trooper pump fuel in the on positon if so. What would cause no power in the fuel pump relay and the fuel fuse. I even took the fuel relay out when it did have power to the pump and it would still pump. I'm bummed because the thing has been sitting there for months now. :oops:
 

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What engine? The quick answer is the pump runs for a couple seconds when the key is on. If the engine is not being cranked over it shuts off. Safety feature in case of a wreck, fuel pump will not continue to run unless the engine is running or being cranked over to start.
If the engine is running (at least on the V6) once the oil pressure is up the fuel pump can get it's power from the oil pressure sending unit. This can explain why an engine with a bad relay will still run, once it cranks enough to build oil pressure.
Someone jump in and correct me if needed, but thinking at the moment this is correct.
 

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Do a search for fuel pump not running and then spend the next 3 days reading. I'm lazy tonight and this is covered weekly. All zoo's work similar. Key on fuel pump till system pressurized. When engine starts then juice from alt takes over and triggers the fuel pump relay. If you search you will find the jumper test to check if the pump or alt is bad. 1/2 time it's the pump 1/2 the time it's the alternator that keeps it from running. No it doesn't just run with the key on.

Welcome to the planet.
 

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Discussion Starter · #4 ·
Airhead rider said:
What engine? The quick answer is the pump runs for a couple seconds when the key is on. If the engine is not being cranked over it shuts off. Safety feature in case of a wreck, fuel pump will not continue to run unless the engine is running or being cranked over to start.
If the engine is running (at least on the V6) once the oil pressure is up the fuel pump can get it's power from the oil pressure sending unit. This can explain why an engine with a bad relay will still run, once it cranks enough to build oil pressure.
Someone jump in and correct me if needed, but thinking at the moment this is correct.
It is the 4ze1 2.6.
 
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