2000 chevy s10

[2000Xtreme]

its a 2000 chevy s10 xtreme 4.3l......truck wouldnt start....thought it was the fuel pump.. bought a new one... still didnt fix it... i cant hear the fuel pump running when i turn then key... the relay is good. please somebody help me

[SUPERDAVE22]

Did you change fuel filter? Could be clogged up, could also be maf sensor

[Leeann94astro]

Are you sure it's a fuel issue? I would check spark, both to the coil and from the coil.

[2000Xtreme]

well i dunno i just cant hear the pump running

[rhandwor]

Go to Advance or Auto Zone get a loaner fuel pump pressure gage.
http://www.autopart.com/tools/toolsmain/tool/T_3430.htm
Did you check the fuse and use a test light or DVOM and check for power to the pump. You can also run a temporary 12 volt supply of power for test purposes. Check the fuel pump ground look along the frame.

[spuds704]

It could be the oil sending unit. It's designed to cut off the fuel if you have no oil presure, sometimes they fail (even if you have presure) the sending unit will not pass current to the fuel pump.

[MT-2500]

Originally Posted by spuds704

It could be the oil sending unit. It's designed to cut off the fuel if you have no oil presure, sometimes they fail (even if you have presure) the sending unit will not pass current to the fuel pump.

That is a old wives tale.:sarcasm1:
The oil pressure switch is not a fuel cut off switch.

It Only runs the fuel pump in case the fuel pump relay relay fails.

[spuds704]

Originally Posted by MT-2500

That is a old wives tale.:sarcasm1:
The oil pressure switch is not a fuel cut off switch.

It Only runs the fuel pump in case the fuel pump relay relay fails.

I had an 89 S10, drove to my local gas station and filled her up. Got back in and it turned over but wouldn't start. Pulled it home and started checking, no current to the fuel pump. Dug out the Chilton manuel and looked at the wiring diagrams. Current runs through the oil sending unit, changed the unit and it ran great. If it was a backup for the fuel relay you would have two sorces of current to the fuel pump.

[MT-2500]

Originally Posted by spuds704

I had an 89 S10, drove to my local gas station and filled her up. Got back in and it turned over but wouldn't start. Pulled it home and started checking, no current to the fuel pump. Dug out the Chilton manuel and looked at the wiring diagrams. Current runs through the oil sending unit, changed the unit and it ran great. If it was a backup for the fuel relay you would have two sorces of current to the fuel pump.

Yes it is only a back up and the fuel pump can /does use have two sorces of power.

They are wired parallel,
but.
Fuel pump relay first and no. one.
Oil pressure switch if relay fails.
But both ARE WIRED TO THE SAME ING FUSE.

Look ar your wiring diagrams again.
The oil pressure switch to fuel pump power is wired parallel with the fuel pump relay.
Either one can power fuel pump.
But fuel pump relay has first choice.
The oil pressure swith to fuel pump is only a get home saftey if fuel pump relay fails.
Both work off of the same ign fuse and if fuse blows you are still a dead duck.


The fuel pump relay feeds power to fuel pump key on prime up and engine cranking and engine running.
As long as that circuit does not fail the oil pressure switch is just along for the ride.
But is ready to supply power to fuel pump if pump relay quits.
Also on engine cranking and running the oil pressure has to come up before oil pressure swith kicks in power to fuel pump.

Make real slow starts.

Later years GM even done away with the oil pressure awitch to fuel pump to save money.

2000 was one of last years it was even used.

[MT-2500]

PS
The 2000 S-10 4.3 W engine wiring diagrams does not even have a oil pressure switch for fuel pump.
Gm is saving there money there.

[spuds704]

Originally Posted by MT-2500

PS
The 2000 S-10 4.3 W engine wiring diagrams does not even have a oil pressure switch for fuel pump.
Gm is saving there money there.

OK, it was something I remembered from the past, should have checked the diagrams first, you've convinced me, and you know how hard it is to convince an old wife.

[MT-2500]

You are welcome.
Glad you got it figured out.
It is on of the most Miss understood and a hard system to explain.
A lot of people still think it is on there to kill engine in case of oil pressure loss.
Good Luck

[MT-2500]

For proff of hard to explain.

Check this post.
http://www.automotiveforums.com/vbul...d.php?t=966362