No power to fuel pump

I had a rear u-joint cut loose at 70mph. My 98 4runner is a 3400, 2wd, automatic with 336,000 miles, in excellent shape, well maintained, and is my everyday driver. It was a u-joint I'd replaced. (I assume the c-clip didn't seat as well as I thought.) Besides the driveshaft, damage was minor. There is a slight ding on the fuel tank skid plate and a light scratch on the tank itself. But the engine shut down when it happened (two weeks ago) and has not re-started since. If I straight wire the fuel pump, it runs, so the pump itself seems ok.
One 2 wire harness on the cross member above the rear axle was damaged when the shaft cut loose, it has been repaired. The pump relay and EFI fuse test ok.
Still no power to the pump.
Suggestions? What am I missing?

 

Check your COR (Circuit Open Relay).

You should try and get the FSM for your car. The diagram I have for 2002 shows the COR is in line with the fuel pump power.

 

Given that it's job is to shut the fuel pump off in the event of an accident, being in direct line with the fuel pump makes perfect sense. The COR has 2 halves, essentially. One for the starting cycle, one for the running time. If the correct conditions aren't met, it will shut the fuel pump off.

It's an easy to replace item, but many people either miss, or skip, it in their troubleshooting.

Good luck!
Pat☺

 

I don't think my 98 has a COR relay. I can't find a listing for it anywhere. I am wondering if any of the wiring harnesses above the tank are damaged. I don't know anyway to check short of lowering the tank.

 

Are you getting voltage at the pump relay? If you have voltage across the relay with the key on, then it's somewhere after the relay and towards the fuel pump. You'll need to verify the wiring.

If you have no voltage at the relay, it's going to be towards the ignition switch I think.

Regardless, get a wiring diagram for your car. It will save you so much time. It shows all the wires and junction locations, pinoyts, etc.

 

I have voltage to the relay and the relay tests good. I have voltage to the sending unit with ignition on, but not the pump. However, when I engage the starter, I show voltage at the pump.
I'm working on the theory that I have further wiring damage, maybe above the tank? Maybe wiring was snatched out? Tomorrow morning I'm planning to drop the fuel tank far enough to see any wiring above it. I'm not sure where else to go.

 

Could this be correct behavior, though?

If you have any power whatsoever at the pump...I'd be looking at a relay or the ECU or ignition switch. Once the ECU sees that the engine is running, it should be keeping the pump running.

When you crank it, does it try to start?

From the schematics I have looked up, they all show a COR for 98. I agree, I could not find that part either but this is a schematic for supposedly 1998. There was a schematic for the 4cyl, so I know it's not for 2001-2002. The COR relay is under the dash to the right of the fuse box.

Also see here there are 3 schematics posted that appear to be the same just in a different format: This is from TOYOTA (1998...but no date to be sure):

 

Ran across this... what a legendary truck...

https://www.youtube.com/watch?v=QlNLIu8SIpk

But he has good tips on trouble shooting.

 

I don't see one. I see the blower motor. I see the blower resistor, and on the other side, empty space. But that's hanging upside down in the seat. (at 60 I'm getting to old for that) Tomorrow I'll pull the glovebox out and double check. Im out of time in the shop today.

 

C6 is where it is supposed to be.

 

I found the COR relay and it tests good. The field Pump & COR relay are both the same and both test good.

 

In the video where the guy is getting the truck to run, he mentions that the fuel pump only gets power when the starter cranks the engine. So, it almost sounds like from what you describe, this is working correctly.

Obviously, after the car starts, the ECU must continue to supply power to the Fuel Pump. I'm wondering if this is the issue. This would mean that the ignition switch is bad when you let go of the key or the ECU is shutting it down for some reason. Did you check for any codes?

 

We hear the pump running with straight wire.
We hear/feel the pump running when ignition engages starter. No fuel at the engine line.
I inspected the lines for impact damage, found one pressure line nearly closed. Repaired it.
Still no fuel to engine but we hear the pump running.
Removed inlet line at fuel filter, engaged pump, no fuel coming to fuel filter.
Now we suspect impact damage to either pump or sending unit assy. The next step will be to remove and inspect the assembly and bench test the pump.
Any further suggestions?

 

Yeah, sounds like you have a plugged line. Pull the fuel filter first and run the pump and see if it pumps fuel. Crack the fuel rail and see if you can blow through it with the fule filter disconnected.

 

DRopped tank and removed fuel pump. The nipple attaching the electric pump to the pick-up feed had broken off of pump due to impact damage when rear ujoint failed. The pump was running but just pumping fuel back into the tank. Replaced the pump, 4Runner started right off.

 

Have you get the FSM for your car?