Died while driving.

[FJ80SRT]

Wire harness...

 

[jonheld]

The broken connector is your cold start injector time switch on the top half of the thermostat housing. I believe these are NLA from Toyota, but I'm sure you could find a used one.

 

[jonheld]

The AVS-3 wire seems to be the one that is causing the fusible link (AM-2) to blow.

Please explain "AVS-3 wire" and how do you know that it is a problem?

 

[Tools R Us]

The broken connector is your cold start injector time switch on the top half of the thermostat housing. ...

IIRC, the time switch silliness has power to it, the broken end could/would likely short, causing mayhem?

 

[jonheld]

IIRC, the time switch silliness has power to it, the broken end could/would likely short, causing mayhem?

Yea, I thought about that too. The +12 for both the time switch and injector come off the AM1 link. That doesn't seem to be the one he's popping.

 

[FJ80SRT]

Please explain "AVS-3 wire" and how do you know that it is a problem?

The AVS-3 wire is the one which connects to the gray connector on the fusible link (the one that keeps popping). Just figured their may be a short in that line? I don’t see any part of the wire harness that is in bad shape though. Do you think this cold start time switch. Pups be causing a short here? I’m sorry, IIRC?? @Tools R Us

 

[jonheld]

I never saw the acronym "AVS" in any documentation, so I don't know where that's coming from.
In any case, as I mentioned before, fusible link AM2 feeds the ignition switch, all 6 injectors, the ignition coil and igniter.
If AM2 is the link you've been blowing, then the issue is downstream from the fusible link. Since it doesn't blow right away and only when driving, I suspect a frayed wire or chafed insulation allowing the periodic contact with a ground point.

Having a busted connector with bare ends is NEVER a good idea, so either replace it or tape it up. You live in Texas, so I'm not certain the CSI is doing much good anyway. It adds a periodic squirt of fuel into the intake to make it burn rich during warm up for emissions.

 

[FJ80SRT]

Here is the "AVS-3" wire I was talking about. Notice the the AVS-3 wire, has the gray connector on the end. This wire directly connects to the AM-2 (gray connector on the FL). I traced this wire and have not found any issues. I will re-tape everything. I will also disconnect the CSI time switch. Next, I will re-wrap the foam liner around the wire harness next to the manifold, which has some slight melting (although not all the way through). See picture #101. This runs from the positive terminal to the ECU.

 

[jonheld]

Have you checked the feed to the ignition switch and to the coil/igniter?

 

[FJ80SRT]

Have you checked the feed to the ignition switch and to the coil/igniter?

The ignition coil is in good shape (I checked the ohms) however, I have not inspected the wires from the ignition coil. Although this looks to be good. I have yet to check the ignition switch feed. Although something to note, when I first bought this truck, did have some issues with the keys getting stuck in the ignition....doubt that has anything to do with it. Anyways, what’s the best way about checking the fed from the ignition switch? I will certainly check this next.

 

[jonheld]

You don't seem to understand what you're looking for.
The fusible link that you are blowing feeds +12VDC to the ignition switch, which in turn feeds +12VDC to the injector harness which supplies +12VDC to all 6 injectors. It also feeds +12VDC to the igniter and coil.
Somewhere along that +12VDC path, some wire is making contact with a ground point causing a direct short to ground from a +12VDC source. That is what is causing your fusible link to pop. The AM2 fusible link is the fuse for that entire +12VDC path. Any short to ground from anything that has been mentioned will pop the link. That is its purpose.

You don't care about anything other than tracing out +12VDC feeds to all the aforementioned items. Don't get sidetracked by spark plug wires or anything else that doesn't get a constant +12VDC when the key is in the ON position.

 

[jonheld]

"AVS-3" refers to the metric wire gauge. It is not the "name" of the wire, it is the gauge of the wire. In the US we use AWG to specify wire gauge.

 

[FJ80SRT]

Got it. Although I’m not an expert at reading wiring diagrams, this is helpful. In order to get to the ignition switch, I have to take apart the plastic underneath the steering wheel and look at the wires running to the ignition? Remember, I am only an amateur seeking guidance...

Also, where can I find the injector harness? Pictures would be beneficial. Thanks again @jonheld, your the man.

 

[jonheld]

You have 3 general areas to search.
Left side of the intake: injector harness
Right side of the engine bay: igniter/coil harness
Lower dash: ignition switch

I think the way I would approach this to avoid popping additional fuses, would be to disconnect the positive battery terminal. Attach 1 lead of a multimeter to the fusible link in question (or directly to the white wire with the red stripe) with the other lead of the multimeter connected to the negative battery terminal.
With the key in the ON position, and the meter set to a continuity beep tone, I would perform what I like to call "percussive diagnostics" in the 3 areas listed above.

If you move or shake a wire bundle in a certain way and hear the beep tone of the meter, something in the circuit has touched ground. This should help localize the issue.

 

[george_tlc]

^ and for the continuity beep use a meter that responds QUICKLY to momentary continuity. Some cheap ones (let's call them junk) respond after 1/4sec or more so you'll never know a quick continuity occurred. You can check your meter by tapping the leads of the meter together to ensure it beeps even for a very short tap.

cheers,
george.

 

[FJ80SRT]

You have 3 general areas to search.
Left side of the intake: injector harness
Right side of the engine bay: igniter/coil harness
Lower dash: ignition switch

I think the way I would approach this to avoid popping additional fuses, would be to disconnect the positive battery terminal. Attach 1 lead of a multimeter to the fusible link in question (or directly to the white wire with the red stripe) with the other lead of the multimeter connected to the negative battery terminal.
With the key in the ON position, and the meter set to a continuity beep tone, I would perform what I like to call "percussive diagnostics" in the 3 areas listed above.

If you move or shake a wire bundle in a certain way and hear the beep tone of the meter, something in the circuit has touched ground. This should help localize the issue.

So, I am getting a constant tone from AM-1 (the FL I am holding in the picture) after doing the “percussive dx”... no tone from AM2. What’s my next step here? I see FL leads to the fuse box/IG switch/alternator/30A power?

 

[FJ80SRT]

You have 3 general areas to search.
Left side of the intake: injector harness
Right side of the engine bay: igniter/coil harness
Lower dash: ignition switch

I think the way I would approach this to avoid popping additional fuses, would be to disconnect the positive battery terminal. Attach 1 lead of a multimeter to the fusible link in question (or directly to the white wire with the red stripe) with the other lead of the multimeter connected to the negative battery terminal.
With the key in the ON position, and the meter set to a continuity beep tone, I would perform what I like to call "percussive diagnostics" in the 3 areas listed above.

If you move or shake a wire bundle in a certain way and hear the beep tone of the meter, something in the circuit has touched ground. This should help localize the issue.

So, I am getting a constant tone from AM-1 (the FL I am holding in the picture) after doing the “percussive dx”... no tone from AM2. What’s my next step here? I see FL leads to the fuse box/IG switch/alternator/30A power?

 

[FJ80SRT]

So, I am getting a constant tone from AM-1 (the FL I am holding in the picture) after doing the “percussive dx”... no tone from AM2. What’s my next step here? I see FL leads to the fuse box/IG switch/alternator/30A power?

 

[jonheld]

Stay with me here. Why are we looking at AM1 when AM2 is the fusible link that is popping? Are you popping AM1? NO. You are popping AM2. Therefore we MUST assume that AM1 and its associated circuitry is good. If it wasn't good, you'd be popping AM1.

You're likely getting a continuity beep tone on AM1 because the dome lights are on, but that's just a guess on my part.

 

[jonheld]

Stay with me here. Why are we looking at AM1 when AM2 is the fusible link that is popping? Are you popping AM1? NO. You are popping AM2. Therefore we MUST assume that AM1 and its associated circuitry is good. If it wasn't good, you'd be popping AM1.

You're likely getting a continuity beep tone on AM1 because the dome lights are on, but that's just a guess on my part.