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Re: fuel pump not working
There is a starter relay that will cut fuel of if the vehicle is not getting spark. Do you have spark at the plugs? If so there is also a fuel cut off relay that is in the trunk of car. You just have to push this to reset it. The one in the trunk is for safety and is pretty common for it to shut fuel off because it thinks the car has been in an accident. I would start with the trunk relay first because I have seen them activate at wierd times( big hills, bumpy roads, and hitting curbs).
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Two of those wires are for the sending unit for the fuel gauge .The pink with black stripe is B+ to fuel pump , black is ground for fuel pump other two are for fuel sending unit . There is all so a relay in the under hood fuse box for fuel pump an fuel shut off inertia switch . Before messing with fuel pump wiring check if inertia switch is tripped , Check out this videos on fuel pump circuits . Fuel Pump Electrical Circuits Description and Operation
Check for power output at the relay, there should be a pink wire with a black stripe that connects to the fuel pump relay, when the key is turned on it should have 12 volts for a few seconds, then drop to 0 volts. This is the prime function that builds fuel pressure before you start the engine. Even though it clicks it doesn't mean it works - the contacts could be bad. This wire continues straight back to the pump, if it has power there may be a damaged wire between the relay and the pump or a bad pump - the pump is fairly common on these vehicles.
These pumps last longer if you don't run less than 1/4 tank of fuel - keeps them cooler.
If you turn on the key and you do not hear the pump in the tank running for two secounds ( the same time your warning lights on your dash light up and goes off) then 1 you need to replace the pump or 2 it has low voltage to the pump or 3 both. I just repaired a 1987 pioneer what you need to know is the pump requires 12v at the pump, however OEM has placed an inline ballast resistor located on the driver side front engine compartment near the hood latch that is made of white ceramic with two connection both wires are orange with a black stripe. A. Check the voltage on both sides of the resistor 12v in 12v out use a volt meater - to battery + to resister if no voltes check the relay the passenger side of the engine compartment ( there is 4 relays from front to back it is no. 2 from the battery) looks like a small blue box newer relays are black, if they do not click when the key is on then your CPU may be bad or fusible link is bad If you have voltage to the resister and you have 12v in and less than 12v out your next test will be at the rear connector to the pump, three wires close to the fuel filter using a volt meater check the black wire with the orange / black stripe if voltage is less than the voltage out of your resistor then there is a bad wire in the system and a new wire is required. confirm this by jumping the battery to the pump wire black to- and orange to + the pump should run. Note. running the pump with lower than 12v will damage the pump and cause it to fail! If the pump works you can check the fuel pressure on the fuel rail, remove the cap to epose the shearder valve (looks like the valve on your tires) depress the valve stem and fuel should come out, caution fuel is under pressure have a rag under the valve to catch the fuel, if low pressure the pump is bad and/or filter is plugged Replace filter first recheck this test then replace pump and recheck. Note!!! when the pump is out of the tank recheck the voltage at the pump this will show true voltage at the last connector it needs to be 12 volts! Reconnect the pump wire the stock wire and check, on the pioneer I worked on was 4 volts so I rewired it to a new battery source using the orange /black strip wire that had 12v in to resistor as a trip wire for a 65 amp power relay. The owner noted an increase in overal performance " it now has more power now" hope this helps
The plug you are referring to is probably the fuel tank pressure sender not the fuel pump. It would be plugged into a black sensor about 2 inches long pushed into a rubbergrommet on the fuel bung. The fuel pump connector would have more that 2 wires going to it. most likely a heavy purple wire would be the power to the pump. It has to have 12 volts to it to work. The sender may have 3 wires, 5 volts, ground, and sense. the pump connector would have 12 volts, ground and 5 volts for the fuel gauge sender down in the tank.
If the 12 volts is not there, check the fuel pump relay. it is usually up on the drivers side firewall.
With the key in the on position without starting the engine, you should have 12 volts to the pump for 3 seconds then it will click off. Without cranking the engine you should be able to locate the relay by the clicking sound.
There is also the obvious, like checking the fuel pump fuse.
Have you had the fuel pump output pressure checked....Sounds as if it could be defective.....Pressure should be above 3 .6 bar Or maybe check your battery condition, that may be the problem, but more likely the pump....
You should have 12 volts at the gray wire.The black is ground make sure and use this wire also.This way you know the ground is good also.When you turn the key on you will only get battery voltage for 2 seconds with the key on.If you crank the motor then you will get battery voltage also.Hope this helps.Good luck.
I think you have a bad fuel pump relay. The contacts on the relay have burned. thats why you have 13 volts when check it with a meter, but no pump. when you put a load on the circuit you have a voltage drop because the contacts in the fuel pump relay won't let enough current flow. Either that or you have a bad ground to your fuel pump. Alldata.com has all the wiring diagrams you need to diagnose this problem. good luck