restored power to injectors

Anything to do with wires for me is never easy. I can do stereo stuff but I gotta work hard to do that.

Anyway, I check grounds for continuity, all good there

now here is where Im lost. all the power wires come together in 2 places. The yellows stay on their own along with the white. With the yellow wires #3 and 4 come together then join #1 and 2 later. here is a pic of what im seeing. It confuses me. Not the best pic, Im not a photographer
 

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There is no broken wires anywhere.
The Yellow wire goes into the dash. Im guessing to the ignition.

Could that have anything to do with it?
My guess would be no but Im learning a lot here these last couple weeks

Im gonna try to locate another ecm and see if its not that. Im running out of options. Everytime Ive ever had a problem like this its always been something simple that I have over looked. I need another set of eyes to look at it in person

I do appreciate all the help everyone here has given.
 
Just follow your injector wires from your ecu all the way to your injectors. Check both your ground and power wires. Also check the pins on each plug and make sure they look good.

Also keep in mind that just because there is a wire going from one place to another doesn't mean that it isn't corroded or broken inside the shielding. If you have access to a multimeter do a continuity test and make sure that you're getting a good signal from one end of the wire to the other end. If not then cut and splice in a new wire.
 
It could be your ECU but you already said that you're getting about 12 volts at pin NO10/E01 and NO20/E02 when the ignition switch is set to "on" right? If so then I doubt that your ECU is bad.

The first attachment is the ECU pinout. Make sure that the pins on e01, e02, no10 and no20 are clean and free of corrosion on both the ecu and harness side. Also make sure that the pins are seating fully when plugging the harness into the ecu.

Next, use a multimeter and do step 6 of the second attachment. If you're passing that inspection then your ECU should be good.
 

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Last edited:
#10-Eo1 failed got 32 millivolts

#20-Eo1 passed got 10.2 volts

Gonna test again later to see if I messed up. In the meantime Im gonna look for an ECM
 
It might be your ECU. I thought you said before that you're getting 12v at those pins so I ruled out your ECU.

If you do replace your ECU make sure that you only use a 89 ECU. For your year 4runner you cannot use any other ECU than an 89 model due to the injectors being a different impedance.
 
I have looked at ebay. I have a hard time spending that much money on a "maybe it works"

I found one locally for $40 that the guy said worked when he took it out a couple years ago.

Thinking almost of just having mine rebuild by Jet so I can rule it completely out.

Things to think about. But for now its time for beer and relaxing while the woman is gone
 
It is very rare for an ECU to go bad. But if you're not getting the proper voltage at those pins on the ECU then your ECU is definitely bad. Seeing as the bad voltage test directly involves your injector problem then I think you're on the right track.
 
Back the drawing board. I cant leave well enough alone. I redid the test. got 12.24 volts on both sides. ECM is good. What else is there that controls the injectors?
 
Then it's the wiring. Somewhere between the ecu and the injectors you have a bad wire that control the 1 and 3 injectors. Start doing continuity tests on the harness and find your bad wire.
 
Rechecked for continuity. got it in all wires. Now I was hooked into #10 to start with. Starting with injector #1 I checked the white wire, all good. For an unknown reason decided to check the yellow wire while still connected to #10. Had continuity. It was that way with all 4 injectors.

Now I dont think I should have had continuity in the yellow wires. My ignition was off.

Am I wrong in that theory? In the loom they never touch.

Tomorrow I might change my ignition out just for giggles, or at least look at the wires there.

I dont think my problem is between the ECM and the injectors. There has to be something else to do with the ignition or something. But this is all electrical. Again not my strong point
 
Were all of the check done with the harness unplugged from the ecu? If not, unplug the harness and do it again. My money is still on the wire harness.
 
There's two things that control those injectors: The ECU and the wire harness. The only other thing I can suggest is to pull your engine wire harness from your vehicle and strip the factors covering off of it and replace the wires that control the injectors. That way you'll know for a fact that the wires are good.
 
Ive had that thought. Its probably gonna what Ill end up doing.

If its only the ECM and the harness that controls the injectors where does the yellow wire go? I have tracked it as far as going into the dash.
 
At this point without actually being able to check it out for myself, all I can tell you is that I am still confident that it is a wiring issue in your harness somewhere between the injectors and the ECU. I don't have access to an 89 specific wiring diagram so my advice may or may not help you as to where the yellow wire goes. I can tell you that an 88 and earlier models have a resistor on the fender that those two wires would go to. Since yours does not then I would assume that the yellow wire is a common ground for many different sensors and components. With that being said, each wiring harness has many different points where they are grounded to the vehicle. So, back to my original advice is to pull your engine wiring harness and cut it open. Mark which plugs are your 1 and 3 injectors. Cut the loom open and inspect or replace all wires going to those injectors.

FYI: If it's not worth it to you to repair that harness, you can ask around on yotatech and pirate4x4 and maybe you can find a harness specific to an 89 4runner. I replaced the harness on my 88 because the p/o rat FU^KED the whole thing. I paid about $150 for mine but I found mine that was in mint condition and un molested. Normally you can find them for between $50 and $100 shipped.
 
The yellow wire splits out of the loom just before the ECU and goes up into the dash. Thats why I thought maybe to the ignition. Its about a 12 ga wire if that helps for thought.

I called wrecking yards in my area and 1 has a harness for $50 that they just pulled from a running 4runner.

Im gonna go do some more checking on the wires. I gotta be missing something somewhere.

If I cant find anything Ill go get the harness later this week if I can get off work early enough
 

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