94 1FZ Engine wiring harness issue/question

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hisandhers80s

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I pulled my engine wiring harness to do a refresh and found a jumper wire running from one of the injector plugs to another. I have not uncovered much of the harness except where the heat tape was near the EGR. Any idea why someone might have “installed” this jumper wire?

On the plus side I do not see any melted wires where the harness passes the EGR! But this jumper make me think there is a short or broken wire some where else along the harness that I have not uncovered yet!?!

Thoughts?

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I missed that the OP was working on a 94 model.
 
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82121-60342 for the '94/Jan '95 is long gone. I wish it wasn't so.

If you know of one in a box, I have a use for it.

82121-60343 for the Jan '95/'97 is still available...but isn't a direct replacement for the 2nd gen engine because of the CPS, or lack thereof. And other stuff I can't think of at the moment.
 
Can only really be a ground wire...if that's your only casualty, you're doing ok! I'd suggest replacing all of the injector plugs while you have it out as they get very brittle due to age and heat back by the EGR. I had a random misfire and found that my #6 harness plug had basically disintegrated and was just "floating" on the injector. I also had one of the knock sensor plugs just fall off when gently handling. Good thing is that you can find all of the necessary replacements pretty easily, and having on the bench makes life much easier for repairs/rebuilding!

I found a spare used 93-94 harness on eBay when I was working on mine, but decided to save that one and repair what I had. Not 100% complete, but pretty close and could easily be refurbished if/when needed.
 
CrabCake said:
Can only really be a ground wire...if that's your only casualty, you're doing ok! I'd suggest replacing all of the injector plugs while you have it out as they get very brittle due to age and heat back by the EGR. I had a random misfire and found that my #6 harness plug had basically disintegrated and was just "floating" on the injector. I also had one of the knock sensor plugs just fall off when gently handling. Good thing is that you can find all of the necessary replacements pretty easily, and having on the bench makes life much easier for repairs/rebuilding!

I found a spare used 93-94 harness on eBay when I was working on mine, but decided to save that one and repair what I had. Not 100% complete, but pretty close and could easily be refurbished if/when needed.
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Pretty much the path I am working on at the moment. I have ordered heat tape, reflective material for around the EGR, working on ordering as many of the connections as I can locate (including all of the injector plugs and both knock sensor plugs, and the 3 different temp sensor plugs from the side of the head). I got a bunch of adhesive heat shrink and Insultherm fiberglass high-temperature loom, as well as a de-pinning tool set. I am going to refresh all the loom, tape, and wrapping on the entire thing. I also have a used harness on the way, just in case.
 
@hisandhers80s
If you find a harness side connector housing for the round green temp sensor, LMK. I couldn't find one (new) when I cleaned up my harness. The sensor is available everywhere, but not the harness side connector housing.
 
No, it's the round one
 
CrabCake said:
Can only really be a ground wire...if that's your only casualty, you're doing ok! I'd suggest replacing all of the injector plugs while you have it out as they get very brittle due to age and heat back by the EGR. I had a random misfire and found that my #6 harness plug had basically disintegrated and was just "floating" on the injector. I also had one of the knock sensor plugs just fall off when gently handling. Good thing is that you can find all of the necessary replacements pretty easily, and having on the bench makes life much easier for repairs/rebuilding!

I found a spare used 93-94 harness on eBay when I was working on mine, but decided to save that one and repair what I had. Not 100% complete, but pretty close and could easily be refurbished if/when needed.
Click to expand...
You were right! The ground going to the gray plug is not inside the sheathing, so the jumped the ground from the plug next door!

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Malleus said:
@hisandhers80s
If you find a harness side connector housing for the round green temp sensor, LMK. I couldn't find one (new) when I cleaned up my harness. The sensor is available everywhere, but not the harness side connector housing.
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If this is the one you are looking for, I found it from my local Toyota dealer in their online parts store. Part number I used is 90980-10156.

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EDIT: the number I have in my notes is 90980-10412, but it appears that connector housing is listed under both numbers (must be a vendor thing). -10412 isn't listed anynore, but -10156 is. I also discovered that I have two verions of the Wiring Harness Repair Manual, RM1022E, and only one of them has both numbers listed. I must have been using the one without the dual listing when I was working on my harness. I'll post the "better" version on the Resources forum.

Good find!

That's the one. however, I was working on a '95 harness and the number may not have been the same; I have to check my notes. It is showing up as available, so if it works for both 2nd and 3rd gen harnesses, I need to buy a few.

Thanks very much!
 
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hisandhers80s said:
You were right! The ground going to the gray plug is not inside the sheathing, so the jumped the ground from the plug next door!
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A quick note regarding injector wiring.
All injectors get +12 on the BLACK/GRN (pin 2) from the ignition switch. That jumper is +12, not ground.
The ECU grounds pin 1 to fire each injector. Please refer to the Toyota EWD.

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jonheld said:
A quick note regarding injector wiring.
All injectors get +12 on the BLACK/GRN (pin 2) from the ignition switch. That jumper is +12, not ground.
The ECU grounds pin 1 to fire each injector. Please refer to the Toyota EWD.

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Excellent info as always!
 
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