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tow440, ASE Certified Technician
Category: Chevy
Satisfied Customers: 31
Experience:  24 years shop owner/technician, electronics background
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1998 blazer low fuel pump pressure - will not start. Fuel ...

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1998 blazer low fuel pump pressure - will not start. Fuel filter has been changed.
Hi.. What are you getting for a pressure reading? these engines like all the pressure when starting.. even 10 lbs low will cause a hard start. more than likley you need a new fuel pump. if you change the pump make sure that you check the wiring plug as the fail at the connector to the harness. we try to use a factory assembly as they come with the new harness. if you have access to a gauge the fuel pressure should be 60-66 psi key on engine off. you need to cycle the key a few times as the pump should run for aprox 2 seconds every time the key is energized.

let me know how you make out.

a quick test to rule out ignition problems is to spray a small amount of carb clean into the intake and see if the engine fires over.. this will confirm good ignition, timing,compression etc..

tow440 and 6 other Chevy Specialists are ready to help you
Customer: replied 9 years ago.
The presure is between 44 to 52. The pump was replaced 12/05. Engine will fire over. Will the pressure sensor above the tank cause it not to start? Does the battery play a role in this which appears to be good?
The pressure sensor is for the evap system and not affect the engine running, you pressure is too low, the battery should have a full charge to be accurate as low voltage will cause the pressure to be low. is the 8th digit of the vin a w ?

Customer: replied 9 years ago.
Yes, its a w.
I would have to say that you need a fuel pump. I would check and see if there is a warranty on the pump you had installed previously, some company's warranty them for 3 years. again make sure you check the harness, I would check this first when you drop the tank.

Customer: replied 9 years ago.
A friend just completed an OBDII check engine with two results 1) PO452 (voltage signal from the pressure sensor in the evaporative emission contrl system is two low for the engine operating conditions) & 2)PO453 (same but to high). Does this make any sense? How can one be low & at the same time be high? Is this the sensor or fuel pump or something else?
I would check the wiring at the top of the fuel tank, the wires to the sensor might be shorted or open, the sensor you are talking about is on top of the fuel sending unit and they might have been damaged when the last pump was installed. the sensor is the black one in the picture above