Now I went and double checked some things with my multimeter and I am not getting 12 volts at my ign fuse. Could this be my issue not getting 12 volts to b+ and if so why wouldn't I get 12 volts at that fuse.

 

Hi Ben, If you read voltage between one leg of the fuse and the other that means that fuse is busted. OR fuse is not making good contact with supply side and load side.

 

No voltage across the circuit one part of multimeter at fuse one at ground. But rad4runner I'm not getting 12v at b+. Efi fuse is good and so is ign fuse.

 

You'll need to research that circuit. I thought the ignition and EFI fuse were supplied by the same power source but I could be wrong about that. You need to find out if the B+ is upstream or downstream of the ignition fuse. That will tell you which direction to go. Start at your battery and work your way to the outside fuse box and then to the B+ at the diagnostic port. There are some fusable links along with some large fuses in and under the box that you may need to look at. Sorry I can't help you out more with this. Find a drawing of that circuit and you'll find your problem.

 

After some reading this morning it looks like my main relay may be bad does this sound right if I have voltage across EFI fuse and EFI fuse is good, but no power to B+?

 

No, B+ is BEFORE the COR. (You wouldn't be able to bypass the COR with FB-B+ otherwise.)

Vocabulary: if you have 12 volts ACROSS the EFI fuse, the EFI fuse is open (blown). (The voltage across a dead short is always zero.) Did you mean you have 12v TO GROUND on each side of the fuse? If that's only with key-on, that's good.

That tells you your problem is after the EFI fuse and before the B+ terminal, but there's more in there (wires, connectors) than just the relay. So don't go swapping parts willy-nilly. Pull the relay, and test it. Then look for the appropriate voltages on the relay socket pins. (What are they? It depends on which pin is which. You probably have a diagram printed on the relay, so you know that the relay coil needs ground on one side and key-on voltage (through the IGN fuse) on the other. The contacts need 12v (through the EFI fuse) on one side, continutity to B+ on the other.)

 

I know this is lighting up on an old thread, but hopefully some of you can give me some help.

I have an 88 4Runner (22re) that is having trouble getting power to the fuel pump. It's a bit different than Ben's situation. Here is where I am at:

• I know that it is getting air and spark (inspection/starting fluid).
• I can directly wire up the fuel pump to the battery at the last connector (2 prong) before the pump and the engine runs well (I know its not safe, just needed to move the vehicle).
• I jumped the Fp to the B+ at the diagnostic connection point under the hood (in hopes to bypass AFM/OCR), but no power to the pump when starting.
• I inspected the OCR and it seems to work fine. Nothing looks burnt inside, the capacitor isn't leaking, etc. Resistance is where it should be according to FSM.
• When the OCR is plugged in, I only get 8-8.5V coming from B+ to Fp. This seems problematic, but I can't find anywhere that has normal voltage drop. I was also using a paper clip that was loosely placed in the back of the connector to the relay, which could also be a source of voltage drop if it isn't getting a good connection, but with the tight cable/space, I can't splice into the wire.
• When I jump the B+ and Fp at the OCR connector, no power to the pump even through it has 12V at the B+ and Fp of the connector (checked with multimeter)
• I tried checking for continuity between the blue wire at the fuel pump connector (2 prong) near the fuel pump and the blue Fp wire at the OCR connector, but there wasn't any. According to the schematics that I have seen, it is a direct line from the OCR to the fuel pump. Is this my problem? I tried to trace the wire, but I can't figure out where it goes without disassembling the dash.

Does anyone have any suggestions as to where to move next? I'm hoping that there is an easier/less intrusive solution than tear everything apart and trace the wire. I'm at a loss for the moment and just can't seem to get it.

 

Have you checked the fuse on the drivers side under the dash. It is a 15 amp fuse on the bottom left when you are looking at it, but you can find the fuse reference on 4crawler.

 

try not to pollute multiple threads. you asked this exact question in another older thread. bump that one, and link to others that might be similar.

 

Thanks for the response, Ben. The fuses are good (only blown one is for the dome light, but I'll tackle that another day). I'm assuming, looking at the schematic, if I'm getting power at the OCR, then the circuit is clear up until that point?

 

Thanks for the response, wallytoo. Any advice about the question at hand (4Runner) to go along with that?

 

You should try to stick to one thread.

The good news is that you have done an excellent job of trouble shooting. I think you have a broken connection (in the blue wire) between the COR (I assume that's what you meant by OCR) and the fuel pump.

Let's back up a step to make sure you're not going off the wrong way. With key-on, you should have 12v TO GROUND at B+ (measuring the voltage between B+ and FP is measuring something else, but that too should be 12v). If not, suspect the EFI relay. FP should be a straight connection to the fuel pump. You know the fuel pump is good, and the fuel pump is less than 10 ohms, so you should get low resistance (< 10ohms) between FP and ground.

I understand you DO get 12v at B+, and open circuit (infinite resistance) from FP to ground.

You can re-check this by removing the COR and checking the resistance from pin 1 (which goes straight to the fuel pump) to ground. (Heck, you can check for continuity from pin 1 to FP, which should be continuous (very near to 0 ohms).

Now you just have to find the break in the blue wire. But if the tests above pan out, it would be safe to run a new wire from the fuel pump blue wire back to FP. It's slightly red-neck, but it preserves the safety function of the COR-VAF circuit.

 

I'll keep that in mind. There are so many threads that have this issue. I didn't find this one until later on in the day and thought it would pick up more traction. I went ahead and modified the other post to link it to this one.

Thanks for the helping me with this, scope103. I agree with you that the connection (blue wire) between the COR and the fuel pump is most likely. Any chance you've ever traced that line? I'd like to follow the same pathline, but can't see where it goes without completely disassembling the dash. I was hoping someone would know if there was another connector somewhere down the line or where it goes, so I could maybe snake a wire back through.
(mini-rant: Why the heck it's back there and so difficult to get to idk. I wish the wires were long enough for me to pull it away from the tiny spot its in and get behind the connector. This inspired me to search for mods where people have moved those relays from behind there to a new location (easier to get to and more water resistant) and even modified the 2-in-1 COR relay to just (2) separate more widely available relays)

With the key on, I do get 12v to ground at B+. I meant to say that after I jumped the B+ to Fp, I was getting 12v from the Fp to ground (just to show the jump was successful, measured from the opposite side of the connection), so in theory, the pump should be getting power up to that point. Sorry for the confusion on that.

Thats what I was thinking, so I just clipped into the connector right before the fuel pump and measured continuity there. All good. I then clipped into the opposite connector that I thought ran directly to the COR connection and I got no continuity (infinite).

Again, thanks for the help on that. Looks like I am on the right track. I'll keep the thread updated.

 

This might help:


My EWD says the fuel pump line is pin 8 of BG1. BG1 is described as under the passenger seat.

 

You rock. That is better than what I am working with from the factory manual.

 

it's possible the diagram won't apply to your 88 4runner; in fact, it's highly likely it won't. the pickups and 4runners tend to have different routing. also, the diagram is probably for a later model, circa 1993. i don't recall any wires under the passenger seat in my 87 4r.

wally

 

Actually, a 1994. And wallytoo knows much more than do I about pre-'90 vehicles.

 

If you have 12V at FP, you should also have 12V at pin 1 of COR and pin one of pump. All three points are connected by the blue wire. If one point does not have 12V the blue wire must me broken somewhere.
If you have 12V at pin 1 of fuel pump, but it's still not running, either the ground side of the pump is broken OR the pump is broken.
The simple solution is to dive in there and find where that break is.
The blue wire should lead from C.O.R. to the fuel pump, so most logical route would be the wire bundle running along the passenger side threshold , then on the floor along the right side body panel to the fuel pump. It's not that difficult to remove the plastic threshold, unwrap the bundle and look for your blue wire.

 

First off, thanks for all the advice with this.

I was afraid that the wiring went back behind the dash, through the wall and back under or even through the body somewhere. Knowing that it went down the threshold helped locate it. I pulled out the passenger seat and threshold and found the connector. Not sure why, but the PO had poorly spliced in about 8 feet of wire, which led to a loose connection. I took out the splices, checked everything, crimped a new connector on, and tagged the lines. It's all wrapped up, neat, and back in order.

I really appreciate the help!

 

Cool!
The P.O.'s idea of a kill switch? LOL! Kill it when you want it running.

As I have often emphasized, Toyota components are bullet-proof. The problems arise from the poor way they are connected or put together.