Fuel Pump Voltage

[casey_wa]

Re: my 1983 Civic 1500.

Am wondering what is the voltage to the fuel pump. I have a service manual but it does not state the voltage. The problem started with the car warming up for a minute then dying like it was out of gas. The testing procedures in the service manual suggested replacing the fuel pump relay. This did not correct the problem. The fuel pump relay(s) measure 2 volts, with a surge to 3 volts every five seconds, at the output to the fuel pump. Similar voltage was measured at the fuel pump. Different opinions have been that the fuel pump is 12 volt with another being 2 to 4 volts.

The fuel relay receives its signal from the negative side of the coil. These pulsations tell the relay the vehicle is running and to send power to the fuel pump. The coil tests are within the acceptable limits.

Additionally, the negative side of the coil has a blue wire to the fuel relay and a blue wire to the distributor pulse generator/ignitor. The only question with the ignitor test is that the manual states there should be continuity with the positive probe to the black/yellow terminal with the negative probe to the blue terminal and NO continuity with the positive probe to the blue terminal and negative probe to the black/yellow terminal. In reality, the opposite occurred. I am not sure if this indicates the ignitor needs replacing or if this is a misprint in the manual since a different misprint had been located and misprints do happen.

Not sure if the ignitor is somehow influencing the fuel relay or if the fuel pump is 12 volts then what is causing the relay to send out only 2 to 3 volts to the fuel pump.

Any thoughts are appreciated.

Casey

[cvcc_wagon]

i am not sure if the fuel pump relay is the problem. my service manual has a testing procedure, it sayes to connect the two yellow/black wires at the pump cut-off relay by the fuse panel. it then tells u to disconect the fuel line from the filter under the hood (the filter is a small metal cilinder with one hose coming in the base and two hoses coming off the other end to the carb) tehn u to turn on the ignition on for 60 seconds with a container under the free hose and you should have no less than 480cc or 17 oz of fuel. if you get nothing the pump is dead. if you get less than 17oz the rear filter is clogged. if the filter is clogged you should probally replace the front one as well. if all goes well and you get 17oz and you are still wondering what is wrong with my car it is probally the relay and you should go to a wreckers and pay the 5 or 10 dollars the charge you.
i didnt follow all of your last paragraph but according to the wireing diagram of the fuel pump system the signal from the coil is low voltage signal like you were talking about

The fuel relay receives its signal from the negative side of the coil. These pulsations tell the relay the vehicle is running and to send power to the fuel pump. The coil tests are within the acceptable limits.

the wire that powers the pump comes directly from the battery to the ignition switch (the yellow/black one), from there it goes through a 10A fuse to the relay so to answer your orogional question the pump is 12 volts

[Muncha]

Hey man i had the same Problem, Try replacing the Main reley. It contorls the fuel pump. My crx was doin the same thing and when i replaced it the problem stop. Here is a sit that will tell you were the main reley is on the car and how to replacew it or fix the relay..hope this works man.. http://www.crxsi.com/resources/repai...ng_main_relay/

[StiffyLS]

I have this same problem too, but I can't find the relay anywhere locally, and it's quite expensive at the places I've found. Sometimes my engine will cut out up to 5 times in 15 minutes of driving. For a temporary fix, I wired a switch to bypass the relay so when my engine dies because it's not getting fuel, I can flip the switch to get it pumping the fuel again, works pretty good, but still annoying shifting into 2nd right when your car dies.

[fastz06]

Originally Posted by StiffyLS

I have this same problem too, but I can't find the relay anywhere locally, and it's quite expensive at the places I've found. Sometimes my engine will cut out up to 5 times in 15 minutes of driving. For a temporary fix, I wired a switch to bypass the relay so when my engine dies because it's not getting fuel, I can flip the switch to get it pumping the fuel again, works pretty good, but still annoying shifting into 2nd right when your car dies.

i've got a '94 citroen ax gt. it's got the same problem than yours. i can drive in 3rd, 4rd or 5th and sometimes next to a curve or a ascention it just wont accelerate. like you i have to shift it in 2nd to put the pump working correctly again. maybe the pump is unclean.
i hope so because as you say, they are very expensive...

maybe in a junkyard you find something but in this case you can never be sure if it still works!