Fuel pump voltage

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RB2
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Post Thu Apr 02, 2015 6:25 pm

So my car decided not to start today

I've worked out it's not getting fuel

I pretty sure my pump is dead as it's doing nothing at all

I've checked the voltage to the pump but it was only 9.5v

The battery is fully charged.

I was expecting 12v to the pump.

Could this be the issue if so any thoughts on the cause of the drop.

I would expect the pump to still do something in 9.5v


Cheers for any input.
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Brianmoooore
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Post Thu Apr 02, 2015 6:35 pm

Voltage readings such as these are virtually meaningless, unless qualified by the conditions the readings were taken in.
If you measured 9.5v with the pump connected, then that's about what I'd expect with a locked rotor, but if taken with the pump disconnected, then it simply means there is a series resistance of several megohms between the battery and the pump.
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RB2
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Post Thu Apr 02, 2015 7:04 pm

The reading was taken from the plug with the pump disconnected.
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Brianmoooore
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Post Thu Apr 02, 2015 8:14 pm

Was the crankshaft turning or the pump relay bypassed?