Need Help (Fuel Pump Issue)

So I know you probably see posts like this frequently however I am currently at a loss.

I have a 2001 4runner and well it won't start. First thing I noticed is the fuel pump doesn't prime or do anything once you turn the key on. Now I am at an impasse as to what the issue could be so I am asking for help/suggestions.

Vehicle cranks no issue. Has spark just no fuel.

Things Replaced:
EFI Fuse
EFI Relay
Fuel Pump
Fuel Tank Relief Valve
ECU Fuse

Current Issue:
Fuel Pump still doesn't prime
Only 5V at fuel pump plug

Current Idiot Lights on Dash once key is turned to ACC:
Check Engine
Check Oil
ABS
TCS
Park Brake
Battery

Confirmed not getting fuel at the engine.
Confirmed Spark
IGN fuse in cabin found blown - Replaced Fuse

I'm now banging my head against the wall as this thing is now a boat anchor that I can't seem to figure out the issue of. Looking for things to check/ideas of what to look for. I'm huge on DIY and working on my own vehicles HOWEVER at this point if it's electrical....that is the one thing I HATE!

Looking for any help on this!

 

You get 5V at the pump plug but what do you get right after the relay and or fuse? I'm not sure which goes to the pump as I don't have a wiring diagram.

If you are getting 12Vish up front then its the wire going back. Or could be a bad ground as well but need a diagram to see where that is.

 

Toyota has a device called the Circuit Opening Relay. Essentially 2 relays in one case, one energized during the start sequence, one during the run operation, that runs the fuel pump, as long s the engine is running. If the engine stops, like during an accident, it will immediately shut the fuel pump OFF. It prevents the fuel pump from dumping fuel out of a broken open fuel system during a crash. Safety feature, and an important one.

Having gone through all that, it can be a show stopper for starting the truck. There are a ton of "how-to" threads on how to check that it's operational, during both the start cycle, and during the run time. Look up COR Relay, or Circuit Opening Relay for information on hot to test and verify it's operation.

Or you can just presume it's gone bad on you, which they do. It's located directly above the engine ECU, behind the passenger side kick panel.

Is that any help?
Pat☺

 

Pat,

This is one relay I haven't checked. I have instructions on how to check the relay itself and other things but this one didn't occur to me. I'll be checking it when I get out of work today. I'll update once this is checked.

 

I am not an expert on any Gen, but if I am not mistaken the ECU needs to see a signal from the crankshaft position sensor to send power to the fuel pump. Somebody had the wire diagrams on a thread here, and I think the fuel pump is activated by a signal from the ECU.

 

Disconnect the connector to the fuel pump and see if you get 12v or still 5v.

If you get 12v at the plug (not the pump side) then the pump is drawing down the voltage somehow. If you didn't use a TOYOTA or a Denso pump, I'd suspect the pump or the wiring in the tank.

If the connector has 5v when disconnected, I would assume you have a short and bad wiring somewhere from the ECU. I would put 12v to the power pin to the pump and see if it runs. You can also see if the car starts. You will still need to track the bad wiring down back to the ECU.

 

I have 5 volt when not connected. To be honest I've had the fuel tank out several times and there just isn't enough cable out of the truck (about 4") to test it without unhooking the entire thing again......

So this swap out it tried to start like it got a burst of fuel then just died again. I'll be re-wiring the fuel pump connector and installing a new one. And swapping out the fuel filter.

 

I used a US Motor Works full assembly to replace the pump. The nightmare of wiring will probably begin this weekend.

 

I found a wiring diagram I saved on my phone from something else I was looking at and found it helpful. I think it may be all inclusive. Hopefully there’s something that can help you if not this time maybe something else.

 

This diagram is for the 4th gen.

Factory Service Manual for 3rd gens used to be floating around and is invaluable for this sort of work.

 

I hope these schematics for 1997 4Runner helps, if anything is not clear let me know