LSD Rob

The truck is a 92 with the 22re. Replaced the fuel pump and when turning the ignition on I do not hear the pump prime what se ever. Have the fuel filter off as well to see if any fuel comes out the line. That is a negative. So now I'm chasing down the two wires, one is solid blue while the other is white with black stripe. Does anybody know which wire would be ground and what one is power? And what the volts should be to the wire? I have also replaced one of the two relays that would cause the pump to not prime. Any help is greatly appreciated!

-Robert

Aussie22r

To test the ground, test from the pump to the frame, one wire will give you continuity (dead short or very low ohms) The other wire will give 12v when on.

Remember though that the fuel pump will only run when the AFM flap is open so you'll need a helper to test for voltage.

rustypigeon

You can turn on the fuel pump by placing a jumper wire between terminals +B and FP in the DLC in the engine compartment.

LSD Rob

I tried +b and fp but that was a no go.

rustypigeon

You had the ignition on right?

The Blue wire is the + wire. With the +B and FP terminals jumped, you should have 12 volts going to the blue wire when the ignition is ON. If you do not have 12 volts, you have either a faulty EFI main relay, or a faulty "IGN" fuse, a faulty EFI fuse, or an open wire somewhere.

Check that and let me know what you find.

EDIT TO ADD... if you still don't have 12 volts at the pump with the +B and FP terminals jumped and the ignition on, check for 12 volts at the +B terminal of the DLC. If there is no voltage at the +B terminal, you have narrowed down your search to the EFI main relay, EFI fuse, or IGN fuse, or the associated wiring. You can assume at that point all the wiring to the pump is ok.

LSD Rob

Still not getting a reading at the positive wire, efi main relay is brand new and fuses are good. When I put the volt meter on all it would do is give a screeching noise.

LSD Rob

Just checked the blue wire all the way back with a test light and it shows I have power.

LSD Rob

Well the pump works now without any issues.

rustypigeon

Did you find anything wrong, or did it just start working on its own?

LSD Rob

Well I messed around with a couple of wires, then unplugged the main relay, efi relay, and efi fuse, then plugged them back in and I had power. Pump still doesn't prime with just ignition on though. It should though right?

rustypigeon

The fuel pump does not run with the ignition on in a Toyota. During normal operation, when the engine cranks, its sucks in air. This airflow is sensed by the Volume Airflow Meter. The VAM closes a set of contacts which energize the Circuit Opening Relay. The Circuit Opening Relay then closes a contact to power the fuel pump.

This is a safety feature which makes it impossible for the fuel pump to run without the engine running. The only way to override it is to jump the +B and FP terminals in the DLC. This simply bypasses the VAM and the COR and runs power right from the EFI main relay to the pump.

Here is a wiring diagram that shows what I am talking about...
http://www.wiringdiagrams21.com/2010...wiring-diagram

tacoma83

on my 1994 toyota 4x4 v6 the pump dont kick in untill u turn the motor over. we thought the same thing u should here the pump kick on i even got down there and listend to. i took the line apart at the fuel filter and the gas shot right out when u turn the motor over. guy that works at toyota a buddy said those pump really dont ever go bad.

LSD Rob

Well in my case my old pump actually did go bad. Had no fuel what so ever. Thank-you rustypigeon you have been very helpful.

Torlog

I had that kind of problem with my 89. It turned out to be corrosion coming out of the EFI fuse going to the relay. The relay did not get enough power to sygnal the pump. I replaced the wire and fuse assembly going to the relay. No problems since. It sound like you might have the same with pulling the fuse and relay and putting them back in. You could not see it without the fuse out and looking. Hope this helps.

hcobb32

I know this is an old post but I need help. Have 91 ext cab 4wd 5 speed manual 3.0. The fuel pump is def good cause I took bed off and checked it by hooking it directly up to battery. My problem is it won't pump when trying to crank the truck. I tried the jumping +b and fp and that doesn't work either. BUT if I run a wire directly from either +b or fp directly to the battery the fuel pump will work. What could be causing this? What exaclty does jumping the fp and +b bypass? Does it bypass the efi relay or open circuit relay? I've heard other ppl say different so I don't know. the truck did crank when I sprayed fuel into the throttle body so I know it's a fuel issue. Am I jumping it correctly? Will jumping work if the relay is bad?

scope103

FP goes directly to the fuel pump, so connecting 12v to FP will make the pump run.

B+ comes FROM the EFI relay, which gets 12v from the EFI fuse, which gets it from the battery. Between B+ and FP is the COR.

So when you jumper 12v to B+, when the COR closes the fuel pump runs.

Following so far? You never tested B+ (measure voltage to ground; with key-on you should have 12v), but I'll bet your EFI fuse is open or your EFI relay is not closing. Without 12v on B+, jumpering it to FP doesn't do anything.

And lay off with jumpering 12v to connectors at random. You could end up putting 12v to something that really doesn't like it. The correct test would be to use your multimeter to check for voltage on B+.

wyoming9

iTrader: (1)

Fire departments love responding to vehicle fires when they take out the garage and house.

Speaking from experience

hcobb32

thanks scope it's more than likely my efi relay. I'm just confused on that. If the efi relay needs to be good to jump the 2, then what is the point of jumping them? I thought the whole point of jumping them was to see if the relay was bad in the first place. If all relays were good then there would b no point in jumping because u would pretty much have ur problem narrowed down. Do u understand what I'm asking ?if a fuel pump doesrnt come on u jump everything to see if the pump itself is still good. Maybe I just got the purpose confused

rustypigeon

Jumping FP and B+ bypasses the COR and the AFM. Here is the circuit...

scope103

A picture is worth a thousand ....