Weird temperature sensor

So Saturday I got a 2002 Toyota Tacoma from a dealership. I believe it's the base model. I had a mechanic come out from yourmechanic and he did a pre-purchase inspection. He seemed pretty knowledgeable and like he knew what he was doing. He said it was a good car and I trusted his expertise so I made the purchase. It's pretty well taken care of and it looks like the previous owner knew what he was doing with it. There are a couple things that I stuck out to me though. The first thing is the engine temperature sensor or gauge (not sure which one). Apparently something wasn't working so the original owner rerouted things a bit. There's a temperature sensor attached to coolant hose (see pictures). The mechanic I hired said it wasn't an issue (and neither were any of the other things I'll mention) and it's basically just rerouting things. He said it's likely from electrical issues that the previous owner couldn't fix (I'd like to know if I should correct this and if it's worth correcting). The next thing is the blue tape. I'm not sure what to make of it. Is that something to worry about? The third thing is the picture with the zip tied and closed off hose(?). I'm not sure what that is. And the fourth thing is there is a slight clunk sound when accelerating from a dead stop or when going from first to second gear (automatic transmission). I'd like to diagnose this sound and see if it's a u-joint, or something more serious, like a symptom of a transmission failure to come. I paid for six months of insurance but I was able to get a deal for 18 months for the same price. I clarified to make sure that it covers any major problems and he's had yes, so if the transmission ends up having a serious issue, they'll cover it 100%. I don't know much about cars, but I did have a 1998 Toyota Camry. I put about $1,000 of work into it all by myself and none of my work failed once on any repairs. I say that not to brag just to give you a good idea of where I'm at with my knowledge and skill. It was up to 251k miles when I sold it so I have a pretty good understanding at my level. Anyway thanks for your time. Thank you for having me here. Here's pictures of my truck and the first three issues mentioned above. Cheers!

216k miles

 

Welcome to TW

 

Thank you!

 

Welcome!

That owner really liked their truck; they replaced the bench seat and crappy steering wheel from those of another model Toyota.

Looks tasteful (and I bet they're much more comfortable too).

The temperature monitoring used though is a bit odd...they could've opted for an OBDII style plug-in since the ECT sensor supplies data out through the OBDII port for easy monitoring.

It's possible the gauge, or sender, is out. This isn't necessarily a bad thing simply that the ECT sensor does not display coolant temperature on your dash and instead is used to communicate with your PCM.

The gauge and sender are independent from the above mentioned sensor.

 

Thank you! Won't lie they are pretty comfortable. You can tell the previous owner really took care of this car. The condition you see is the condition I got it in. I'm kind of disappointed there's nothing broken I can mess with haha. I think I'm gonna take it to a mechanic to diagnose what the metal clunking is and what I can do to correct the temp sensor.

Any idea about the part taped up or the other part?

 

Lets go backwards.....

that nipple on the top of the engine on the intake plenum is the vac supply for the power steering solenoid on the older (pre 2001) tacomas...

After that they went to an electronic solenoid...so that nipple on yours should of been plugged/capped right off the assembly line....

so yours doesn't need that....

 

Next is the blue tape....that on mine is the fresh air supply to my charcoal canister.....

there's a combination of hoses/tubes that go across the top of my radiator all the way to the other side.

Looks like your missing that hose......your sucking in unfiltered air.....shame on you...





Or you could eliminate that hose by using a little mini filter instead....










This valve has to have a clean air supply from somewhere.....
and dont think a vacuum line is good here...

 

As far as the temp sensor.....as long as its the one for the guage.....who cares....
could be placed anywhere in that return hose area....dont have to be on the head....

Wonder why they did that....I would investigate that further for sure.


Thanks for the pics....damn sure dont see that every day......
....in fact yours is the first......

I've accumulated a number of different work arounds from you guys crazy ass ideals......







Just a heads up.....by splitting that radiator hose ....you introduce an additional two failure points....

when these hoses are cut non factory......they have a high probability on getting leaks in-between the plys.....I've seen it happen many times.....especially that one ...its the hot hose....

Maybe the factory cuts are seared or sealed on the cut ends......

 

Every year or so these trucks change slightly...

here's a evap diagram closer to your year.

https://www.tacomaworld.com/threads/evap-code-help.772290/#post-27645245

 

Thanks for all the information. I went and got a miniature air filter for that and I'm fitting it right now. Next I'll be trying to find where the clunk is coming from when shifting. I can't tell if it's idle to first or first to second but I'm gonna start at the u-joint, motor and transmission mounts first. I'll update this post with information.

 

That valve on the right side of the engine bay is where the blue tape port connects on the intake box. That supplies clean air to the EVAP canister, which is underneath the bed on this year truck. @Tacomahound555 I would recommend installing that line back to factory. There is a hard line that is supposed to be mounted by the radiator, but you could just get some fuel hose and run the whole length with that.

 

What's the part number for the hard line or where can I get it? I can't find it anywhere

 

I believe this is it: 17361-75010

Called "TUBE, AIR, NO.1"

Practice using https://www.toyodiy.com/parts/
You can find any part number if you just know how to look for it.

 

Thanks for that! I'll definitely use it. I looked up the price for the line and it's pretty pricey so I ended up going with the mini air filter for now. Should work either way as long as it has filtered air right?

 

The filter would need to go on the solenoid valve, but yes it will work fine. I just suggested getting some fuel line and running it all the way across. You might need 5’ to go the whole way. Try looking at junk yards for the hardline, I doubt it would cost much used.

 

I would imagine one lead is ground since the sensor is ungrounded. The other probably goes to the gauge.

 

I fixed that temperature sensor. I took off the wire to it to see if I get a reading for the gauge, nothing. Then I found the sensor that sends a reading to the gauge and changed it, and took off the wire again. Worked like a charm. Looks to me like the previous owner got the two sensors mixed up. Either way it's fixed now and tomorrow I'm changing the coolant hose.

 

Yeah its not wise to cut up the hottest hose on the engine....

In fact this is the one to keep an extra behind the seat.