Broncoman

On the back of the engine(3vze) there is coolant manifold thingy(technical term). If you are looking over the back of the engine starting on right(passenger side). You have a sensor with a black plug, Then sender for the temp gauge, another plug with a grey connector, then in front of that you have a sensor with a bluish plug. What is what? I am sorta confused.

Black plug?
Brass sending unit- Temp gauge on dash
Grey plug? - This is the temp sender for the ecm?
Bluish plug in front of grey?

Keep in mind this is a 3vze with auto and 4wd. I know there is a Water Temp Switch that is wired to the A/C Cut Relay. Is this the blue plug?

So that leaves us with the black plug. What does this do?

MudHippy

The black plug should be the cold start injector time switch. But the colors of each sensor/sender/switch/connector can vary from year to year, or if they've been replaced with aftermarket parts. It's best to identify them by their positions. Each wire connector will have a unique shape and will only plug into it's specific sensor/sender/switch.

Seen from the front of the engine, right to left, they are:

1. Engine Coolant Temp Sender
2. Engine Coolant Temp Sensor
3. Cold Start Injector Time Switch
4. Engine Coolant Temp Switch
5. TVV/BVSV for the EVAP

PNC 89422 is the Engine Coolant Temp Sensor
PNC 89462 is the Cold Start Injector Time Switch
PNC 89428A is the Engine Coolant Temp Switch for the E.F.I.(not for the A/C, or the A/T)


PNC 83420 is the Engine Coolant Temp Sender


PNC 23262 is the TVV/BVSV for the EVAP


Here's a thread that also has the correct info on the locations of all of them.
http://www.toyotanation.com/forum/sh....php?p=3251158

*PNC = Part Name Code

Broncoman

okay so if you look at this picture:

Blue Arrow: Engine Temp Sender for gauge?

Red Arrow: Engine Coolant Temp Sensor for EFI?

Yellow Arrow: Cold Start Injector Switch?

Green Arrow: Engine Coolant Temp Switch?

Forward of the green arrow out of sight is the TVV/BVSV

this just doesn't look right to me.

Yellow should be the sender for the gauge right?. Straighten me out.

MudHippy

Well, that is a bit odd. They're all in the "wrong" spots, except the ECT sensor. And what's with that hose connected where the CSI time switch should be? There's no such hose on mine, or any of the others I've seen. Wierd.

Not to worry, I can tell just by looking at them which is which. Regardless of where they are.

Blue arrow: Engine coolant temp switch
Red arrow: Engine coolant temp sensor
Yellow arrow: Engine coolant temp sender
Green arrow: Cold start injector time switch

I'm 99.9% positive I've got that right.

I'm gonna go look at mine to be extra sure...

Yep, that's what mine look like, just in different locations.

Mine looks just like this one(with the ECT sensor in the empty hole of course). Circled in red is the engine coolant temp switch.

Broncoman

Okay you confirmed what I thought was what. I have a 93 and it looks identical to the above image I snagged off this site when I was searching. You and the service manual had me lost because you and the service manual did not have the sensors in the correct location for my application.

What year do you have? It looks as though they added one hose and rearranged the sensors.

Swim

Hmmm... Mine looks like the one with all the arrows. I have that strange hose too. 94, Auto.
I've never seen it before though.... and honestly, I have no idea where it goes. I just went to install this on the new engine today and am confused

sb5walker

The 92-95 3VZEs have a different arrangement of sensors on the coolant outlet than the 88-91 trucks did. Just to confuse matters, I guess.

Swim

That would make sense. Actually looking at it, I believe the big hose connects to another hose on the firewall.... looks like it goes to the cab

banoobee17

i have the same problem so where is the the blue connect to cause idk either....PLEASE HELP

Swim

Ok, so in that photo. The blue Sensor with the square plug... How important is that? My actual wire snapped off the plug on mine and I have no idea where to get a new one. Does anyone have a wiring harness laying around that they can cut one off? Can I leave this unplugged? Help.....

MudHippy

Where is the blue connect to? Blue what? Do you mean the blue sensor? Or blue connector?

Either way they should go togethor. Blue matches blue. Of course that's not always the case. The connector that plugs into my blue sensor is actually clear(no color).

Like has been stated the blue sensor is the engine coolant temp switch, if that's what you're wondering.

Blue sensor square plug??? I assume you mean blue sensor with a rounded plug.

How important is it? Important enough.

If the wire is snapped off the plug, then just pull the plug apart and reconnect the wire. Shouldn't be that hard to do. They're made to be serviceable that way. If the wire isn't long enough anymore, then splice in a short piece to make it a little longer.

I wouldn't leave it unplugged.

Swim

MudHippy - I owe you a growler of Alaska's Finest. You seriously saved me a ton of time. I did some surgery to the plug and managed to get some extra wire attached. Looks good as new.

Seriously, if you come up this way, look me up. I owe you a scenic flight and some good beer.

camo31_10.50

glad you got this figured out, i was just about to fill ya in on which ones are which lol i had to figure em out too

MudHippy

Yeah, no problem. I'll do just that, should I ever end up in Alaska.

newTOyotas

I would like to figure out where the coolant sensor is that the ECU gets it's readings from which directly effects how the engine idles. My truck has issues with being able to hold a steady idle although the coolant level is ALWAYS full when I check it. I can't make any sense out of the information provided here. The picture with the 4 colored arrows 'may' have finally been broken down correctly, but it is such a small pic that I can't tell one sender/sensor/switch from the other.
I'm guessing that the sensors/senders/switches can be located in slightly different orientations and even colored differently. so maybe if someone could offer a pic of what the connector looks like for the ECU sender?/switch?/sensor? that would have an effect on how the engine idles?

MudHippy

It looks like these on the 89 and newer models. Notice how the tabs are located vs. the cold start injector time switch that's relatively similar in appearance(center in pic below).




Is it going to affect how the engine idles? Possibly. But so could a lot of things.
http://personal.utulsa.edu/~nathan-b...63troubles.pdf

phildelfino

subscribing?

newTOyotas

Well, I'm sure ALOT of things can effect the idle. How does one figure this out though without somehow eliminating components?

MudHippy

Simple. You look in the FSM troubleshooting section under the heading "Poor idling". Determine based on the symptoms which sub-heading applies. Is it "Incorrect first idle", "High engine idle speed", "Low engine idle speed", "Rough idling", or "Misfire"? Then start with number 1 under the appropriate sub-heading and work your way down the list untill the problem is solved. Then you know which components need eliminated/ruled-out, and in which order to do so. How the hell would I know how to "figure this out"? I don't even know which sub-heading applies.

Here's that link again, in case you missed it. http://personal.utulsa.edu/~nathan-b...63troubles.pdf

newTOyotas

MudHippy, I'm sorry. You're correct.