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My car will not start and fuel gauge is stuck on empty

Tiny
SZALKUSKT
  • MEMBER
  • 1992 TOYOTA CAMRY
  • 2.2L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 88,000 MILES
My car will not start and fuel gauge is stuck on empty so I decided to remove rear seat cushion and open panel for fuel pump access. I noticed that there was no battery power to fuel pump black/blue wire with key on. I jumpered positive and fuel pump on the diagnostic link under the hood and that allowed power to go to fuel pump black/blue wire. That led me to look at the circuit open relay. I am just wondering what else or if the circuit open relay located behind the glove box area is the problem. I know there may be more than just the circuit open relay only being the cause of the problem. Is it possible to verify circuit open relay is bad by powering it up with a bench test?
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Monday, January 16th, 2017 AT 11:55 PM

26 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
You should be able to jumper the power contacts in the relay socket to verify that the power gets to the pump. Use a simple test light to verify that the relay is getting the prime signal from the ECM. If that and the power check out then the relay is bad. Or just swap in a good relay and see if the pump powers on.
Run a current draw test on the pump as well, relays usually fail due to excess current draw. Those pumps should not take over three to five amps maximum. Any higher and the pump is on borrowed time.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
Trying to figure out which terminals on the fuel tank is for the fuel pump. There are 5 and only #! And #2 have any power. #1 has 11.49 volts and #2 has 6.59 volts with key on. Which terminals are for the fuel pump. I know 1 and 2 are for the fuel gauge.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
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  • 274 POSTS
Which terminal in the relay socket should have prime signal from the ecm? Is it 12 volts?
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
This terminal with the screwdriver pointing to it is the only terminal on the wiring harness under the dash that will light up the test light with the key on.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
Fuel pump prime and power are both on the same line Blue/Black is POS. White/Black is GROUND. Follow the jumper test below to check the pump.

EFI Main Relay

The EFI fuse supplies constant battery voltage to EFI main relay. EFI main relay provides
battery voltage to +B terminal of circuit opening relay and engine check connector.
1. Depending on model, EFI main relay may either be turned on directly by ignition switch or by M-REL terminal of Electronic Control Unit (ECU).

2. Fuel pump should operate with jumper wire between +B and FP terminals of engine check connector and ignition on. If fuel pump does not operate, check EFI main relay and wiring circuit.

Circuit Opening Relay

Circuit opening relay controls fuel pump circuit. The Electronic Control Unit (ECU) receives an input signal at STA terminal when engine is cranking. Starter signal is also applied to terminal STA of circuit opening relay.

1. Starter signal energizes circuit opening relay during cranking. The circuit opening relay then provides voltage to the fuel pump.

2. On Camry 2.2L circuit opening relay is grounded by the ECU through the FC terminal.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I installed the circuit open relay. I jumped B+ and Fp on the diagnostic connector under the hood. I turned the key on. I didn't hear the pump in the tank running even with a screwdriver touching the tank lid and the handle pressed against my ear. Because of that I disconnected the connector at the tank. I checked for power with a test light and it now lights up at terminal # 4 as in the diagram. I think the pump is getting power, just as a side note, my fuel gauge is pegged at bottom. Since I am getting power at terminal #4 with Fp and B+ jumpped them can we say that the fuel pump is not running. I cant hear it like I said even with the screwdriver touching the toop of the tank and the other end pressing against my ear.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
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When I pull the Fp and B+ jumper out the test light connected to terminal #4 goes out. So I think pump is getting power
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I just checked the #4 terminal while cranking and with everything hooked up as normal and NO jumper wires, he test light lights up while connected to terminal #4 so I think the circuit is good and all the relays are good and the pump is not working. It makes sense because I am also having a fuel sending unit problem. Possibly something wrong in the tank with both the sending unit and the pump assy in the tank? That #4 terminal receiving power while cranking should mean that the circuit is good. Any ideas?
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
Verify the ground side as well. A bad ground would stop both items. If you have a good ground and power, the pump is bad. (Or the wiring in the tank has an issue).
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
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  • 274 POSTS
How can I check the ground? Check for continuity at which pin?
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
Use a test light connected to battery positive to check the White/Black (ground) wire and it's wire on the pump side.
Bad grounds cause a lot of problems.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I removed my pump and sending unit assembly from the tank today. I have not attempted to power the pump itself with battery voltage yet but I did check my sending unit and had an open between the pins 1 and 2 for the sender unit float. I determined the sender unit is bad. By the looks of the rust and gunk all over this thing I am sure that the pump will not power up or run. I will try when time permits as I ran out of time. The filter mesh sock was totally destroyed. I think that the ethanol fuels are just no good for sitting around in a parked car fo many months. I will try power up the pump and see if it works but doubt it. Will let you all know. Here are pics of assembly. Rusty gunky etc corrosion on wires and pins. Terminal 2 and 3 are for the sending unit. 3 being the ground, 2 should give you around 5 volts. Terminal 1 is power to the pump. Nasty
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
O man, you are right that does not look good, I would flush the tank before putting it back together for sure.

Please let us know what happens.

Best, Ken
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
STEVE W.
  • MECHANIC
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I've seen some nasty looking pumps but that one is right up there near the top. Ken is right, clean out as much of the crud in that tank as you can, or replace the tank. If the pump looks that bad I would worry about the tank having pinhole leaks once it's cleaned some. Another option would be a fuel tank liner/sealer like kwik-poly, if you can get it.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I have bought a cheap pump and filter sock from rock auto and I just installed it onto the original hangar assembly. I hooked the 5 pin plug from wire harness onto the connector at the tank. I disconnected the starter solenoid as to not crank the car while I check pump operation while cranking. The new pump operates nice during the test while just having it out of the tank on the rear seat pan. I think it is going to be operable. Since this car is a car that I got from auction basically for noting I am going to put spark plugs in the engine and run the car and if it starts, run the gas out of that tank. My goal is to start and run the car as I have spark and fuel pump working now. I will let you know after I install the pump assembly in the tank and put spark plugs and fire it up. Once I run out all the gas and clean tank I dont plan on using the pump again. I will buy another one with the whole hangar assembly later.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Sounds good
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,577 POSTS
Should work OK, you might need to change the fuel filter a few times.
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I tried starting the car and it wanted to turn over a little but I'm thinking the gas is to stale so I'm gonna siphon the whole tank out put fresh gas and try after that I'm thinking maybe the gas is just to old but I know the pump ran when key was in the start position before I installed the whole thing inside the tank
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I used a little starting fluid too but didn't get the results I was hoping for so I will verify spark again and siphon the tank and put fresh gasoline and maybe disconnect the outlet of the fuel filter to make sure I'm getting flow to the rail
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Thursday, February 25th, 2021 AT 4:13 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Please let us know what happens.

Cheers, Ken
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Thursday, February 25th, 2021 AT 4:13 PM

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