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Tim's Auto Repair
Tim's Auto Repair, Mechanic
Category: Car
Satisfied Customers: 15378
Experience:  Have owned a repair shop for 25 yrs.
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fuel pump relay..crank..Fuel pump would other wise not engage from pcm

Resolved Question:

Truck stopped en-route. Basic trouble-shooting confirmed that if the fuel pump relay is by-passed the pump engages but the engine still would not, although it did crank. Fuel pump would other wise not engage from PCM
Submitted: 5 years ago.
Category: Car
Expert:  Tim's Auto Repair replied 5 years ago.


please explain,,,,does the fuel pump come on for 2 seconds when you first turn the key on?

tell me how and when it started doing this?

do you have any codes in the computer?if so,please give me the codes


Customer: replied 5 years ago.

Here it is. No 2 sec blast. No pump. But, if the pump is by-passed at the fuel pump relay, it will run, although the engine won't engage. What if any, conditions must be met to satisfy the PCM to tell the Fuel Pump Relay to pick-up? and could that possibly be why that even though the pump has been by-passed, the vehicle won't fire.

At this point I'm not interested whether or not pressure is at the fuel rail. Why won't the PCM tell the Fuel Pump Relay to pick-up?

Expert:  Tim's Auto Repair replied 5 years ago.


make sure you don't have any blown fuses.....but

sense it don't come on for the first 2 seconds,,i would think the computer itself is bad...the reason it wont run when you jump the because it don't have an injector pulse..the computer should always energize the relay when you first turn on the key


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