Fuel Pump Stray Voltage

[VDubYah]

Ok Gang I am coming for help. I have worked a 2000 1.8t fuel pump. The pump failed on a out of town trip and was replaced.

The tank was clean,as was the filter on the bottom of the failed pump.

Relay was swapped with a known good relay as part of the trouble shooting so we new the pump was bad.

The relay,fuel filter were ghanged as the replacement pump failed.

An afternoon of testing leads to a constant 1.74 volts at the pump all the time. Testing with a circuit tester shows voltage at prime then voltage with the car running, But the stray voltage is not enough to light the circuit tester.

The voltage is heating up the pump overnight to where it will freeze up and not turn. A "fialed pump was removed and after sitting for several days will run when powered up.

Any ideas where the 1.74 volts is from?

[jfoj]

The stray Voltage is likely a supervisory Voltage from the ECU?? If you remove the connector from the pump is where you measure the 1.74 Volts, or is the 1.74 Volts with the connector on the pump?

You really need to measure the current draw with this "phantom" Voltage at the pump, I would guess it would be less than 4 milliamps or even in the tenths or hundredths of a milliamp?

I doubt this is causing your pump to "freeze" and heat up, but you need to figure out how much current is flowing.

What happens to the 1.74 Volts when the relay is removed?

Strange side question, does your light in your drivers door come on when you open the door?

[VDubYah]

Originally Posted by jfoj

The stray Voltage is likely a supervisory Voltage from the ECU?? ( I was thinking about that but was hoping not to be the problem)If you remove the connector from the pump is where you measure the 1.74 Volts, or is the 1.74 Volts with the connector on the pump? 1.74 at the connector
You really need to measure the current draw with this "phantom" Voltage at the pump, I would guess it would be less than 4 milliamps or even in the tenths or hundredths of a milliamp? Yeah I wanted to but did not have a dc ampmeter at the momentI doubt this is causing your pump to "freeze" and heat up, but you need to figure out how much current is flowing.

What happens to the 1.74 Volts when the relay is removed?
I don't remember Sorry I will have it checked out
Strange side question, does your light in your drivers door come on when you open the door?

I know the door switch is an issue with the drivers door as the pump does not prime when you open the door.

Thanks for you input

[jfoj]

Even most basic multi meters have DC current measurement up to 10 Amps. If you do not have a meter that can measure current but if you have a test light, you can put the test light in series with the pump and see if the test light bulb even glows at all. If it does not glow at all the current is likely negligible.

So do you have problems with the new fuel pump?

What is the issue?

With a bad door switch, you will have priming issues and what you may be seeing is stray Voltage due to the ECM thinking the door is always open?