★ Desperate Need Of Help ★

I am working on rebuilding a 97 Tacoma. its got a 2.7 engine... and it wont run. It starts and will run about 5-10 seconds then shuts off. Like its running out of gas. I put a tester inline right at the tank. its making 15-20 psi of fuel. It makes no pressure until you crank the engine over, and if it doesnt start and you keep cranking it will eventually build to 40 psi.

I have put a new fuel pump in it, new filter sock, new pressure regulator, and a new filter.

I have followed the lines all the way and can find no bends or kinks. Either way, a bad spot in the line, or even a clog would restrict flow and cause it to not run right, but it should still be making the correct pressure at the tank, right???

I have a ton of time/money in this wrecked/basket case rebuild, and I am almost ready to cut ties and part it out.

Is there anything that could/would affect the pump not making pressure???

 

yes, but even if it were clogged, the engine would not be getting the fuel, but hte pump should still be putting 38-42 psi out.... Right?

 

Do you know how I can test the power at the plug to see if its getting the power it needs? I can't seem to find anything on how to test the terminals.

 

Is there some kinda Fuel Cut Off switch on these Tacoma's that activates in the case of a crash???

 

Have you pulled a fuel line off next to the engine to see how much pressure you have up there?

 

12 volt battery to the pump... and I have 45+ psi... now I gotta figure out why the truck is not getting the power to the pump.

 

no. I was pretty sure if anything it would be less than it is at the pump.

 

hmm. just throwing this out there but since it sat for so long you might have to run new wires to the fuel pump. maybe the old ones are to corroded for you to get good juice from your battery. i know im probably no help but good luck!

 

With most if not all electronic fuel injection pumps as soon as the field is energized (i.e; turning the key to "on" position) You should hear the pump run for a couple of seconds, then shut off when the fuel lines are pressurized. ( I'm sure I'm not telling you anything you don't already know) As long as this is happening I might look at other things (if the pump was weak due to a torn or worn diaphram or impeller, the pump would just keep running), keep in mind that the pump would continue to run without the engine being started because it cannot satisfy the call for fuel by the injectors & associated equipment, kinda sounds like a vacumm leak somewhere, need more details as to running condition & what work & parts have been done or changed..... I dunno, post some more info & maybe something will click & make sense & thus a resolution will occur, I probably haven't answered a damned thing you asked for but shit like this (electrical,fuel related crap) ALL BETS ARE OFF !! & you look for anything that may cause your grief.... Good luck & let us know.....

 

Is the fuel pump supposed to come on with the key on the "on" position? or should it only kick on when you start cranking the engine over?

 

as for more symptoms....

I put a 12 volt battery to the pump and I have full pressure... the truck will not make fuel pressure on its own. I turn the key "ON" and I get NO Voltage reading at the plug for the pump. zero... But somehow there is some power going in to it... it will build 15-20 psi of fuel pressure but it will not stay running more than 5-10 seconds. I am now wondering if the power the pump is getting is somehow off the power going to the fuel level sending unit.

the truck fires up. idles smooth for a few seconds then sounds like its running out of gas.

I have checked the connection where the harness comes back into the bottom of the cab floor. its plugged in tight. all the grounds I can find coming off the harness are all grounded.

 

yes the pump should come on when you turn the ignition to the 'on' position as 4WD stated.
another gesture i have for you is unplug the connectors at the pump and see how much power your getting to there.

 

Mass air sensor!

 

None... there is one wire that is for the fuel level (port 2 if I am not mistaken) that has enough juice to barely, and I mean barely light up a test light. On port 4 and 5 there is NO power... will not light a test light or even pick up any juice on the OHM meter. even at the plug inside the cab there is no power on the blue wire (fuel pump power)

I am trying to figure out how to test the fuel pump relay. there is NO power to any wires going to it with the key on. that doesnt seem right to me...

 

could the mass air sensor cause no power to be going to my pump?

The mass Air sensor worked when it came off a Buy Back Tacoma.

 

http://www.aa1car.com/library/2003/us60324.htm