Crackhead resurrection

@RainMan_PNW @shifty`

My new to me ECM arrived today. $74 plus $8 to ship. Swapped everything over, and then read live data.

https://youtu.be/uxfT8BzcZks

Too long, didn't watch version below.
Same issues. Once the truck was warm I still had to shut it off to trick it into going into closed loop so it would read the oxygen sensors. After doing that, everything looked as it did with the other ECM. Same live data reading and zero reading on bank 1 sensor 2 still.

Guess I'm hunting down a wiring harness. Now, I have a dilemma...

Do I buy new from Decatur using the part number that I can get to on my truck??

Do I buy used from flea-bay??

Do I see if I can fix mine?? Not even really sure where to start regarding that.

I guess the first thing I should do is take another reading on the oxygen sensors themselves to make sure the brand new ones are not fucked up....

 

I'd probably splice some new signal wires from the sensor and up to the computer, seems unnecessary to replace the harness if that's the only circuit with an issue.

 

I’d go used from fleabay, wrap every connector with colored tape, install in parallel, swap to it and re-test. Worst case you are out labor time (resell the harness if no change) and allows you to rule one problem out.

 

If it was me, I'd try to fix mine first. I don't know how the harness ties together without poring over EWD's, assuming I couldn't get lucky looking at the ones @RainMan_PNW posted, and this is what I'd be looking for ....

Toyota and others like to wire harnesses like your body, like, run from the ECM (your torso) to a branch/limb (your arm), then to a bulkhead (your hand) then branch out to fingers. I want you to have this visual in your head, if you don't, read it again and try to make a mental picture.

*IF* you find, for example, there's a bulkhead just upstream from your O2 sensors, two possibilities here: 1) You can separate the bulkhead and test for continuity between the harness-end (where your connector) and its corresponding wire in the bulkhead, otherwise 2) you can find a specific replacement harness that goes from the bulkhead to the endpoints you need.

tl;dr - don't make this bigger than it is. Visualize how it's put together so you can choose route A or route B to fix it.

 

Check the continuity in each wire that I mapped out for you in the earlier post (the most recent one that I outlines all of them in). Provided you get a good contact at each end (have a helper, and put the probe or small wire in from the back side like @empty_lord said), you should read almost ZERO resistance (ohms).

If any of the wires reads more than a couple ohms resistance, it’s likely compromised. I would repair/re-run just the bad wires. You’ll find that the Toyota wiring harnesses are pretty extensive, branch all over the place, and are routed through some spots impossible to access without tearing the truck apart.

 

How would someone check continuity from the back on sealed connectors? Serious question.

 

I can help you find the appropriate terminals to replace within the connectors if you figure out what wires are compromised.

 

Good question… hadn’t thought about that really.
I’d probably go in from the front side on those using a pigtail of 24awg CAT5 wire. Just have to be careful not to stretch out the inside of the female terminal or you’ll have headaches later

 

collection of scrap harness pins.

 

Sorry but how is that from the back?

I agree on using spare terminals with a crimp and wire but that’s from the front, no?

Unsealed for sure from the back but sealed? Doesn’t seem possible without compromising the seal with a puncture to probe, right?

 

you cannot easily back probe the sealed ones. front is the only option. with pins.. incorrect pins will still lead to potentially spread pins causing pin fit issues

 

Right - he’s saying on sealed connectors to go in from the front but use a matching size scrap wire terminal to reduce risk of damaging the terminals

 

So I’m potentially mis remembering your advice to probe from the back? Because when you said that it was an unsealed connector? Figures, I have a lousy memory.

 

the connectors he was going after were unsealed yes.

the sealed ones with exposed male pins you can use alligator clamps. but the female pins you shouldnt shove anything but the proper pins into

 

Gotchya. I was conflating the two problems. Crackle has more than one.

 

It's time....

 

YESSSSSSS! You got it!!

I was holding off on replying until you got in. Now I can't remember what I was going to say.

 

Serendipity, I guess. I was away all day Saturday, and when I logged in at the crack of dawn today, there it was...waiting for me! I was afraid I'd have to change my user name to w667

 

Fuck Yeah My Guy!

 

Been really trying to figure out where I want to go with this wiring debacle. Which way would be easiest?

Using the body code (UCK40L) from crackie in this post when we were talking about gearing... and some internet sleuthing on Toyota Parts Deal (TPD.) You'll notice that the one listed on TPD does not have the "L" in the body code. I sent an email asking some questions to confirm fitment. Awaiting reply.



In the mean time, I did a quick searchie search on flea-bay. Found one with a matching number just so I could lay eyes on the part. Pictures suck so it's hard to tell which connectors are where...

Spoiler: Pictures from Flea-Land

Looks like some of it has been drug through the mud, there is at least one connector missing with the pins being gone too! Scary! I don't know at this point in time.

It's been cold, and I've been sleeping a lot lately on my days off. I'm waiting on Bruce (My mechanic) to call me when he's feeling better. He had a Heart attack, and is fine now. Just not up to 100%. I told him to call me when he's ready to listen to my plan. Which was to have him trouble shoot the wiring harness I have, and repair.

Feeling like a stalemate.

 

"L" just means you lean to the left

 

Dem Franchize Boyz - Lean Wit It, Rock Wit It (Dirty Version) - YouTube

How do you just have all this info stashed away like acorns???

 

I know, right?

 

You're way overthinking this one. Repair the wiring you've got, it's only a couple wires from the O2 sensor correct?

Sourcing an unknown condition part to replace a known fault part is always a no. Now if squirrels had been into yours and chewed random wires all over that's a different story

But for a few wires? Repair or replace those wires and move on.

 

You're right, and this is why I love this place. Yall keep my head grounded sometimes. I'll just see what old Bruce will charge me to do that. Plenty of time, but little know-how. Wiring especially in a loom like that is not something I want to trifle with.

 

There's more info like that in the New Features thread created last year. The UCK stuff is under the Model Code pdf....except your year is a crackhead and ain't listed but any of the other years will do !

1st Gen Tundras New Features Chronology | Toyota Tundra Forum

 

Fork! How'd I miss that thread??? Definitely going in the sig-na-toor

 

Gear ratios and stuff is in the Major Tech Specs pdf as part of the New Features thread also !

 

Dropped by Bruce's, and talked to him about my issues. Gave him the full run down on everything I've replaced so far. I asked him his thoughts, and he suggested oxygen sensors. (I smiled in my brain because Bruce passed my test like I knew he would.) I said "I've already replaced all four oxygen sensors, but Bank 1 Sensor 2 is not reading anything at all. Just zero volts at all times. I think there's a wiring problem between that sensor and the ECM. In fact, I've replaced the ECM just for giggles to eliminate that also."

He passed another one of my tests when he told me that some 90's, and early 00's model toyotas won't go into closed loop without a reading from the Oxygen sensors. (Again, another huge smile in my brain.)

He explained that he has some pin-out testing equipment. He can hook up to the diagnostic port in the engine bay, the ECM plugs, and a few other key connectors and it will tell him everything he needs to know. I explained that I already had the glove box out, and the ECM plugs were easy to get to.

He told me that since I've already done all the leg work, and we just need to find where the fault is in the wiring that he would waive the diagnostic fee for me. Just drop the truck off, and he will get to it when he can. I thanked him.

We shot the breeze for a while. Talked about Mom, and Pop. How we was feeling since his hospital visit. Work situations, and life. I told him that I was working a 2-2-3 schedule now, and am only working about 14 days a month now. I told him that I'm getting kinda bored sitting around the house not doing anything, and if he needed an extra pair of hands at the shop to give me a call. I'd be more than happy to come help him, and learn.

He thanked me, and said that was good to know. Some weeks it's pretty slow, and some weeks it's pretty busy. Just depends on how it's going. I told him that I was just looking for something to do, and to learn from one of the best if he'd have me. He said "We'll see, but I've known your family a long time, and I know how you were raised. If I was to call anyone, it'd be you first."

Kinda made me feel good. Hopefully he won't see some of the sketch things I did under the hood, and go "ehhh, I don't know." Lol

 

Evidently, I have a mouse problem also...



Which means that ole niko isn't doing his job, but he is interrupting me when I'm doing my business. Bastard cat.



Looking for mouse eradication advice right meow, or at least deterrents. I think I remember reading about peppermint oil or something like that?