Why doesn't my fuel pump work? it only gets 8.5volts

Question

I have replaced my fuel pump, fuel pump relay, oxygen sensor, starter relay, spark plugs, fuel filter and gas lines, and checked my fuses. my car cranks and cranks but does not start and my fuel pump only get 8.5 volts and i never hear it turn on? please please help with any suggestions. also, i have a security system on my 1988 oldsmobile cutlass ciera 2.5l 4cyl.

Answer 1

bad relay or aground will cause a voltage drop like that,you need to have someone check this one your going to get in deep with tyring to repair this one,have someone check it they might know the cause of what its doing,that would surely save you some money on this car,good luck.

Answer 2

id stop right now. you have replaced lots of parts and havent fixed the problem. you would have come out WAY cheaper if you would have taken the car to a shop to begin with. id have to have the car here to determine what is the problem which is not feasable. tow it to a shop in the morning and pay a professional to check it out before you waste any more time and money swapping out parts hoping for a cheap fix and accomplishing nothing, good luck

Answer 3

Check other 12v sources of power that share a common source of power.   Attack if you see 8.5V on it.  

Check the power feed to the fuel pump relay, and check the relay socket.  Clean the "tar" out of the contacts.

Use the fuel pump test lead to power the fuel pump with a jumper lead.....then check power to the fuel pump again.  (grey wire)

Ok....enough with power.....now check the fuel pump ground lead.  Try jumpering that directly to the battery negative.  (use jumper cables if you have to)  Rust is the enemy.

I do wonder about the ignition switch contacts developing resistance on the computer-related side of it.  Hope the bulb check feature for the "check engine" light works....if not, computer may not be powering up properly.

  I have seen the bulkhead connnector act up on older vehicles.  Make sure you are getting power through it.  Such as the signal to the fuel pump relay.

  The oil pressure switch is in parallel to the fuel pump relay circuit, and can short out resistively, causing a voltage drop.  Unplug it to get it out of the equation.  If it starts up with it unplugged, you caught it.

Answer 4

Check for loose electrical connections/connectors and bad grounds.  MY bet is on the bad ground.

Answer 5

you have a defective neutral safety switch.

Good luck!