dutchboy

Where is the fuel pump relay on a 1990 4runner?
(automatic,3.0)
Thanx.

turborich

fuel pump would be inside of the fuel tank.

algranger

I would guess its in the fuse block under the hood but i dont own anything efi

abecedarian

Fuel pump relay? Do you mean the circuit opening relay by the ECU? That's the only relay controlling the fuel pump that I am aware of.

turborich

duh, my bad. i thought it said fuel pump

dutchboy

abecedarian...my friend,I can always count on your knowledge,but please enlighten me a bit more.
"circuit opening relay by the ECU"...<<<could you be more specific?
I'm not so sure what the " circuit opening relay" is.
I stopped in at the local Autozone yesterday,which this place has always done good for me as far as getting parts...so far. I did a price and availabilty on an EFI relay. $12.99,in stock.
I asked about a fuel pump relay(only because I was familiar with such a thing on my 87 Ford ranger...whichh was nothing short of rolling scrap metal).
The dude at Autozone could not find a Fuel Pump Relay in his system,without a number to go by. This is why I ask,where is the fule pump relay...if their is opne?
I asked a mechanic friend this same question and he is almost certain that the EFI is also considered the Fuel Pump Relay.
Im pickin your brain abe...
:>)

ignatz

dutchboy - The circuit opening relay is located above the ECU on the passenger's side. It's a Toyota specific part. It detects when the motor is running then turns on the fuel pump as opposed to other cars that start the fuel pump when the ignition is in the On position. Have a look at this thread to see a picture of the relay.

abecedarian

There is an EFI relay, but it has little to do with the fuel pump.
And ignatz is correct, sort of....
The Circuit Opening Relay is a two-coil relay that is energized when the key is turned to start the engine (one coil) and once the engine is running (the second coil is energized by the VAFM). Both coils are in parallel and act on the same 'switch' within the relay turning the fuel pump on. That is the only relay that directly controls the fuel pump.
Should be right around here:

dutchboy

Ignatz/Abe...thanx 4 your education.
Now what I'd like to ask is...what are the signs of the Open Circuit Relay when it is not working properly?
My scenerio is,on rare occasions. It will crank great,but just won't fire. Yes,I have spark.
I hate to keep asking,but you guys here on the forums are the best manual I have ever come across. The Chilton's manual doesn't go into extended detail of scenerios or even parts location.
The 2 local Yota dealerships have 3rd graders for mechanics,that honestly...don't know $h*t.
I'm guessin',that if everything is in working order. I should hear the fuel pump come on when I got the key in the on position. Something I will listen for,the next time I start her up.
The price of that Open Circuit Relay is totally,100% out of control!!!
Why?
When almost any other relay (EFI) is $12.99.
And a dealership item only? which makes me cringe as I know damn well,when I go to the local Yota dealership and ask for this specific part...their all gonna go cross eyed and say "what part is it? Never heard of it".
It's their standard response to damn near everything. Again...3rd graders behind the mayhem of the local dealership.
Think I could snag a good one at a yard?

dutchboy

VAFM...definition please?
:>)

ignatz

If you turn the key to the on position and hear the fuel pump running before starting the engine, you should verify that the Coil Opening Relay is functioning properly. When my Coil Opening Relay was bad, that was the symptom. The instructions for checking the Coil Opening Relay are in the FSM here. VAFM = Volume Air Flow Meter. I was able to find a good working Coil Opening Relay at a local salvage yard. I took my multimeter with me and used the FSM guide to verify the used relay before purchasing it.

dutchboy

Thank you ignatz!

scuba

If you need a COR let me know, I have one thats been sitting here for a while that wont sell..

dutchboy

scuba,
I just sent you an IM...yes I am interested.
Please get back to me.
Thank you!

abecedarian

Obvious sign of the COR not working is the fuel pump doesn't work. Hard starting when cold or hot are 'flags' that it isn't working but not absolute results: many things can cause hard starts when cold or hot. Situations that require cranking the engine for more than 5 seconds or so suggest not having enough fuel pressure which also suggests there may be a fuel issue.If everything is working properly, the fuel pump only works when you are cranking the engine and / or the engine is running.
Turning the key on does not turn the fuel pump on. The COR is expensive because it is not a simple relay.
It has two coils to close one switch- not a common relay application.
Volume Air Flow Meter.
Imagine a door that has a spring to keep it closed but opens when air blows through (or is sucked past) the door. It has a sensor and computer to determine how much the door is opened as well as what the temperature of the air getting through the door is. As more air flows, it opens the door more and more, and the sensor tells the computer how far the door is opened. Since you can tell how much air is flowing around the door based on how far the door is opened, all you need to do is know how hot (or cold) the air going around the door is to know the density, and thus how much oxygen (within reason) is getting passed the door. Hot air may move the door farther open but hot air is also 'expanded' (think hot air balloon) so it doesn't have as much oxygen in it.

buckz6319

good posting

deadhed61

I know I'm a little late to this thread but I;m having some fuel pump issues and your posts have been helping out a lot! My fuel pump on my 90' 4runner is not powering on. tested the pump and it works fine. its just not getting any power.

I checked the COR and it is out putting 12V so it seems to be working fine. I'm having trouble tracing the wiring from the COR to the fuel pump to try and find any breaks.

Anybody have any ideas about what else could be wrong if there isn't a break? Are there any other relays that would control/power the fuel pump?

THANKS!!

docmow56

Efi sounds like a good place to start,thank you very much!!!!!!! Jakeman56

Nathan Willetts

hey guys i have a 1994 4runner i traded my 85 straight axle for it and it has a new crate motor but i had to redo head gaskets do to someone not tightening down 2 head bolts well we got it dont and it doesnt start i get fire and spark the motor turns over but doesnt try and run the fule pump only turn on when you try and crank it but not when you turn the key into on can anyone please help me?????

abecedarian

Fuel pump won't run if you only turn the key to "on": it only runs when the key is turned to start / crank the engine to start, then the AFM keeps the COR on, thus the fuel pump running, after the engine has started and is running.