Fuel Pump Relay

[ProjectGreen]

1994 Toyota 4Runner V6 3.0 Liter, 3VZE.

I am working on the Fuel Pump System due to hard start. It is mostly in the morning when it's cold and or the fuel has drained back into the tank (I think). When I turn the ignition to the ON position I cannot hear the Electronic Fuel Pump. I'm told you should be able to hear it when it's "ON". So the Fuel Pump is building pressure in the fule lines in preporation for ignition... as I understand it. Once it's started and running I can hear the Fuel Pump loud and clear (I have the access panel off). So, does this tell me that it's an elctrical problem? I'm all but convinced. Listed below is what I've done, and my plan.

If anything in this post is wrong, please correct me. If you have any advice, please post it in a reply. Thanks.

This is my first time working with/replacing the Electronic Fuel Pump Relay. I went through https://www.1sttoyotaparts.com/ out of Tacoma, WA. They ship for 10% of your order or charge a $5.00 pick-up fee. They have great parts advisors and technicians, and I am local, so it makes good sense for me. If you're looking for a parts supplier, check em out.

OEM Part Number 90987-02009. This is what I thought I needed and ordered:



This goes in this Fuse-Box I believe:




I think this is what I need. OEM Part Number 85910-35010 EFI Circuit Opening Assembly Relay. I will explain why I think this, below the pictures. Can anyone tell me exactly where it goes?





I think this may be the problem to my hard start. I replaced my Fuel Pump because I was told that may be the problem. I also replaced the Fuel Pump Strainer, Gasket, Clip, and Fuel Filter. Since I had already drained the fuel and taken the fuel tank off.

If anybody wants pictures of the above mentioned process, I took a picture of every step. This is literally the first thing I've ever done to a vehicle, never even changed the oil. I took me about 6-7 hours from fuel tank drain to firing back up.

Again, if anybody thinks I'm right, wrong, or an idiot... please let me know. Thanks.

 

[fourwd1]

There are 2 relays that affect fuel pump operation, the Ckt Opening Relay (COR) and the EFI relay. If either relay is bad, the pump won't operate at all.
There is also an interlock switch in the Air Flow Meter that controls power to the pump.
For test purposes, you can bypass the interlock and COR by jumping the +B and Fp terminals in the test connector, located adjacent to the engine bay fuse panel.

 

[ProjectGreen]

There are 2 relays that affect fuel pump operation, the Ckt Opening Relay (COR) and the EFI relay. If either relay is bad, the pump won't operate at all.
There is also an interlock switch in the Air Flow Meter that controls power to the pump.
For test purposes, you can bypass the interlock and COR by jumping the +B and Fp terminals in the test connector, located adjacent to the engine bay fuse panel.

Thanks, I will try it out.

 

[ProjectGreen]

Progress

So I was looking at the wrong relay. It's not one of the two black ones at the top of the photo. It's the one with five wires coming out of it (facing the camera). I unplugged it, the engine would not start. Plugged it back in, it started. I'm going to test all the circuts, fuses, and relays today with a mulitmeter. Hopefully I can eliminate some possible problems. Once it's running it's good. But sometimes it's very hard to start. Very confusing.:redbrick:

 

[KalihiHI]

Wow, nice job finding the issue. My problem is similar but different...my truck starts fine and my fuel pump is definitely working, however my fuel pressure (tested at the LH delivery pipe as FSM says) is 38-40psi with truck on at idle (FSM range: 38-44psi) but then drops to 0psi within seconds of turning off truck. FSM says the pressure should main above 21psi for at least 5 minutes after turning off truck. In researching it seems that maybe the cause of the loss of pressure is my check valve on my fuel pump is malfunctioning/broken. Because my fuel pump is working, is it safe to assume my COR and EFI relays are fine?I have changed fuel filter, new reman'ed Denso injectors, new pressure regulator, all new crush washers, fuel pulsation damper seems fine, and no apparent fuel leaks. I'm thinking I need to drop my fuel tank (or remove my bed??) and replace/service my fuel pump?? Any help is greatly appreciated!

 

[Nina1998]

Fuel issue

Good posts ! I have an opposite issue with 1998 4runner V6. With just ignition switch on, for a few hours while working on trailer lights, engine block filled with fuel and ran out intake, locking up engjne (BAD NEWS). Drained, etc., etc. and got it running again. However, can not locate root cause. The FP relay is ok. It runs perfect. What could be root cause ? Where to check what ? With EFI relay removed it does not pump. So, what to do ???

 

[rwrobs777]

Sounds like a fuel injector stuck open dumping raw fuel into the cylinder but the fuel pump normall
y just primes for about 2 seconds and shuts off.

 

[Fixxer1956]

No power to EFI relay...

Hey yall. Been a long road here lol. 95 4 runner died. No fuel. Thought was filter, changed, no start. Dropped tank, checked pump, pump seemed dead, replaced pump, no power to fuel pump, no start, hard wired pump, pump runs of course, return line fuel pumping, no start, had already checked EFI relay, functioning, checked closed circuit relay, functional, but still no start, found there was no power to EFI. Jumpered efi, starts.

Next step I guess check power to closed circuit relay. But fer sure no power to EFI relay. Yikes....

Andy