Fuel relay and pump

Tiny
TLOST07
  • MEMBER
  • 1997 TOYOTA 4RUNNER
  • 3.4L
  • V6
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
My fuel pump will not come on. The pump is good, I have checked and replaced the relays and fuses and the pump. I have also taken out the open circuit relay and jumped the poles between three and five and the pump then turns on when I turn the key to ignition, but upon removing the jumper and replacing the relay in the connector the pump no longer turns on. What could this mean? Is it likely that the ECU or PCM is bad?
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Friday, February 24th, 2017 AT 12:13 PM

8 Replies

Tiny
KEN
  • ADMIN
Hello,

There is a an EFI relay that goes out in the these cars which can cause the fuel pump relay not to kick on. Also if the mass air flow sensor is having a problem the computer doesn't think the engine is turning over or running so it too will cause the fuel pump relay not to receive a trigger signal. Here is a wiring diagram and a guide so you can do some testing.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please run some tests and get back to us so we can continue helping you.

Best, Ken

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Sunday, February 26th, 2017 AT 7:36 PM
Tiny
TLOST07
  • MEMBER
I have provided some pictures with what I have found in my testing. In all of the pictures provided there is no key in the ignition. And when the key is in the ignition And in the "on" position my test light stays lit fully. Not sure what this means if anything. But the photos show the bulb of the tester dimming and getting bright with the clamp of the tester on the + battery terminal and the probe inserted into one of the efi connector sockets. And your wiring diagram although helpful in knowing what wires go where, did not help me to find my issue. Where can I find my mass air flow sensor? And I'm not sure what to do next.
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Thursday, March 2nd, 2017 AT 9:02 AM
Tiny
KEN
  • ADMIN
Hey,

It kinda looks like you have a ground issue. Can you check the battery to chassis ground wire to make sure you have a good connection please.

Please let us know what happens.

Best, Ken
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Thursday, March 2nd, 2017 AT 10:35 AM
Tiny
TLOST07
  • MEMBER
I checked and re grounded the the battery-chassis. I am still getting a pulsing light front the tester and when I turn the key to ignition I then get no light on the tester in that pole in that connector? Is this supposed to happen?
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Tuesday, March 7th, 2017 AT 10:01 AM
Tiny
KEN
  • ADMIN
Its hard to tell becasue we don't know the color of the wire you are testing. Did you replace the EFI relay as well?

Best, Ken
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Tuesday, March 7th, 2017 AT 11:50 AM
Tiny
TLOST07
  • MEMBER
The EFI relay and the open circuit relay have been replaced and are new even though that wasn't necessary because the old relays we're still good. I have provided a photograph of the two wires that have been jumped that allow the fuel pump to turn on. The two wires in front of my finger are the two wires being jumped. Now, when the relays are replaced and the ignition is turned to on, The fuel pump no longer comes on. I suppose that is my biggest question. , Following that, would be, why will my car not start even though I have the fuel pump running and I have spark.
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Tuesday, March 7th, 2017 AT 2:19 PM
Tiny
TLOST07
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And the wire you were asking about is a black wire with white tracing.
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Tuesday, March 7th, 2017 AT 2:19 PM
Tiny
KEN
  • ADMIN
Black with a white tracer should have 12 volts all the time. Is the test light bright on that terminal?

Best, Ken
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Tuesday, March 7th, 2017 AT 2:47 PM

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