I recently picked up a 1989 4runner with the 3vze and auto trans. I've wanted a Toyota truck for a very long time but they really hold their value. I found this one out of necessity when my DD blew up and I was in pursuit of another beater with a heater.
I paid 500 bucks for her and she came with problems, coolant leaks, idle problems, brake issues, and typical IL rust.
But I like bringing things back to life so I suppose the 233k miles motor has life left in her.

Phase I: While maintaining a DD status, simultaneously Do standard maintenance & fix the Surging idle, leaky radiator, leaky plastic thingy on firewall, fix rear brakes.


Phase II: Fab work! Custom front and rear bumpers, sliders, skid plate, tire and tool mounting, some interior things, body panel "fix", custom tailgate.

Phase III: 33s, lockers, possibly SAS

The very first thing on my list is the damn surging idle. From my research it seems that the coolant sensor in the throttle body can cause this problem, and this would make sense with the rusty coolant and coolant leaks. But there is a little vacuum diaphragm on the back side if the throttle body with a rod that adjust with the engines vacuum. The screw stopper is about a 1/4 inch from contacting it which is obviously wrong. I was thinking the diaphragm would make sense to be controlled by something additional to just vacuum, such as temp. This inspires me to re check the vacuum line routing on the engine before info any further.
My new radiator will be in this week also. Then I need to find the purpose of the black block with all the heater hoses runnjngnto and from it. Appears to be some sort of junction or diverter. It has a nasty leak out of what appears to be a nipple on the bottom.

 

Okay after hours of research it turns out the plastic thingy is the heater control valve. It wasn't making sense because most I found had 2 connections but mine has 3. The third is for the rear heat on my truck.
So that needs to be replaced but it seems that many people have the same issues with it leaking after replacing it. I don't see why bypassing it would be a bad thing? Maybe take longer to warm up?
Any who, I will be bypassing it and seeing what happens. Only problem is that I would also like to flush the heater core but that can't happen today because its -16 right now....lol.

 

 

I Agree need some pics to help out.

Bypassing it should not cause any type of issue. I bypassed my rear heater on my runner and it does not take any extra time to heat up.

 

Sorry, I've only got one or two pics so far. Pretty crappy ones..as I'm sure you know the weather has been rather frigid.
I picked up a Chilton's manual for a 89- today? Strange considering the generation ended in 89. I picked up 6 ft of vacuum line and plugs, I picked up supplies to bypass the heater control valve also.
I found a few things out today...
1. There is a coolant temp switch if some sort unplugged in the back of the engine. My research has shown that there isn't a simple way to tell which is which from a far glance. My suspect is that it's the cold start injector based in the fact its practically impossible to start cold.
2. With the throttle body "air adjust" turned all the way in my RPM is still at the lowest point a steady 1200 rpm and almost always surging. This leads me to believe I have a vacuum leak somewhere.

I also have my eyes on a nice donor body and donor 22re and 5 speed!

 

When dealing with parts people it is easier to refer to it as an 88 model for the most part as it is confusing to them as they tend to think the 89 runner is the newer body style. Most info will work from the 88s. Exception is when it comes to the fuel injectors as 88 is a one year only and that is when it would be best to mention 89.

I suggest getting the Haynes Manual. A Chilton does not cover information as well in my opinion. Looking forward to your build.

 

Thanks for that info!

 

Well found that at some point in the few days I owned it the passenger rear leaf spring mount on the front side ripped away from the fram rust and all...lol. So.I temporarily fixed it with some scrap metal. I'm really Hoping I can pick up this spare frame.

 

Another update. I've been toying with ideas about what to do with the rig since the back half is so rust ridden. I found a spare frame and body from an 84 with a solid axle in front.
But at the same time I thought it would be cool to turn the back into the bed and separate the cab. That's when I found a place called killer toy tops that makes a perfect cab divider! That would solve my rust rear problem and I could patch up the frame.

 

Well I have the throttle body off and the coolant lines were not blocked off but I don't think it had good flow. After staring at the mess off coolant lines I realized that the only reason they were running all over was to reach the rear heat, my rear heater core lines were leaking anyways so I decided to block them off. My plan is to run the heater core backwards. I've done this before and never had an issue. Unless Toyota had the heater core fitted with a check valve it should be fine. This will allow a lot more room to work on the truck with all this extra lines out of the way. It should also lower the highest point a tad.
Once I finish that I'm going to block off the air silencer to eliminate it as a air leak. Then I'm going to run new vacuum lines and clean the throttle body. My maf or whatever its called in the yoga world has apparent chalk pen writing saying 89 runner. This leads me to believe it was replaced from a junk yard.
How can I tell its for a 3vze and not a 22re. And would it matter. I'm assuming yes.

 

Well I've accomplished all of that. Turns out the feed line for the coolant passage in the throttle body was indeed blocked. The previous owner tried all the wrong ways to fix this problem. They backed the throttle stop all the way out, they turned the idle adjust all the way in, "adjusted" the TPS, and then sold it to me. I pulled all the coolant lines and found my leak, cleared it out and cleaned it up, I eliminated my rear heat for now, I re routed the heater houses so the drivers side feeds right into the driver side heater core inlet "outlet" and vice versa. Essentially running the heater core in reverse. My heat works great! Then re installed the TB, reset the throttle stop, adjusted TPS, and the cold and warm idle. Runs like a champ.

 

This was the culprit to my high idle and surging.


This me getting my nose up to purge the air before my modded cooling system lines


This is the flexy situation that broke my rust spring mount away from the frame.


This is my plan for this rig as far as the cab divider and bed go.