[lortech]

Its a 1992 truck 4 cylinder 3re? and went to remove the flow meter box to move open the flapper valve. got no action from the pump. Took out the efi relay after feeling it was hot. Jumped the contact points and the truck started up. Replaced relay truck does not start.

Now, some one explain to me the electrical circuit on this. The flapper valve is there for fire reasons. Should I get in a wreck, with keys on and im unconscious, it will shut off the pump preventing a possible fire if ther is a brake in the line.


The flapper switch sends power to the efi relay on the right fender, it in turn sends power to the pump. Is this correct? is there a fuse? if so where? What should be the normal current draw of the pump? I have a DMM current loop to test current should the bearings in the pump cause drag, thus a near future replacement.

Thanks

 

[fourwd1]

I think you mean 22RE engine, and i guess you're talking about the Air Flow Meter?

Power to the fuel pump goes thru 2 relays, the EFI and COR. The pump gets power via the EFI fuse, but the EFI relay gets power thru the IGN fuse.

I have no idea what your last sentence about testing current of bearings means.

 

[Vicoor]

The ignition switch sends power to the coil on the EFI relay, switching on the relay which sends power to the contacts and one coil on the Circuit Opening Relay (COR).
The COR has to sets of coils, One is energized with power from the starter circuit and is directly grounded, the other gets power from the EFI relay and is grounded by the switch in the Vane Air Flow Meter (VAFM).

You can connect a voltmeter across the +B and Fp terminals in the diagnostic connector under the hood this will show you the voltage drop across the COR. If you have Battery volts there then the COR contacts are open. When they are closed you should have less than 0.5V indicating a good circuit. If the voltage is 0 then check to see if there is Battery voltage at the +B terminal, If so check the circuit from the COR through the fuel pump to ground. If not, check the EFI relay and power supply side.

The best way to check the condition of the fuel pump electrically is to use an inductive current probe and an oscilloscope.

hope this helps

Victor