Funny symptoms

[just66horns]

Hi,
I bought a 90 4 runner v6 automatic 4x4 last month for a grand. I knew I could fix it...
The ebay auction said it stalled when running cold and gave off white smoke. I got it home (towed it 500 miles) and turned the key and it runs fine, but now, I notice that on a cold morning, it runs fine for 1 mile. Then, when I hit the gas at a stoplight it can sometimes die. It will not restart for about a minute, and then I have to crank with the throttle open, and finally it catches. If I don't stall it again, it will take me wherever I want to go for the rest of the day.

Another symtom, maybe related. Also on a cold start, but continues for what seems to be too long. Overdrive will not function on the 6 mile drive home. Seems too warm weather wise and like it should be warm by the temperature gauge... all other times, the OD works fine.

Here is what I'm thinking...
The OD will not function when the engine is cold. The temperature switch (not gauge sensor, but the switch) tells the OD when the engine is warm. So, on cold starts, that same switch is also telling the fuel injection computer that the engine is cold, and floods it when I ease the peddle down. Won't restart because it is flooded, till I clear it out...

Before I get around to replacing that switch, what do you all think? Am I on the right track. I'm going to replace the switch anyway, so, this is a test for yall.

I will find it.

 

[fourwd1]

I think you're on the right track, but I don't know if the same sensor/switch works both the OD and the cold start injector circuit.
My wiring diagrams aren't handy either. You may have 2 problems.

 

[greasefingers]

I think you have two independent issues as well. Vehicles that I am familiar with have a separate transmission temperature sensor that will stop the tranny from going into OD if the AFT fluid is too cold. Then the coolant temperature sensor (engine temp), along with other sensors, provides an input for the computer to help calculate the air-to-fuel ratio.

If the Cap, rotor, wires and plugs are in good shape; then I would concentrate on sensors that play a role when the engine is at idle. Like an Idle air control motor (if that engine has one?) I am not familiar with your year engine. I do like the idea of cleaning the throttle-body & MAF sensor. You believe you have a Vane type MAF.

White smoke is usually associated with a blown head gasket.

 

[just66horns]

symptoms

There are two temp switches that both talk to the ECU. There is also a channel from the ECU to the tranny computer. I think this is an enable signal. White smoke is also caused by overlean conditions. When I bought the vehicle, the toyota dealer had rebuilt the engine for the previous owner, at a tune of $4K for new heads, gaskets and lots more (yes, even though toyota should have covered that on the recall-warranty), and the car had the same problems after the new heads etc...

They put it back together poorly, and I am currently going in to find the issue. I will report what I find. Please continue to post your thoughts, and I will send the correct answers a cupie doll!

 

[just66horns]

Funny symptoms and crappy dealer mechanics

So, the previous owner had put $4K into this engine, and couldn't get it to run right.

I pulled the upper intake off, here is what I found on this new top end...
There are 5 sensors at the back of the engine below the upper manifold. One is a vacuum switch for the charcoal canister purge. It was trashed, top broken off completely. So the dealer had bypassed the switch, and had the manifold vacuum pulling on the canister all the time, creating negative pressure in the gas tank. Every time I pulled the gas cap off, I got a big sucking sound...

Two of the other temp sensors, for the ECU were also non functioning. One was open all the time, the other was closed all the time They switch at 50C and 80C.

Then there was the Fuel injection start timer switch, I could not see that it functioned at all.

The Throttle body linkage was bent, and the dashpot was not being contacted, and the throttle plate was jamming closed, rather than hitting the stop for it. That should be adjusted so the throttle plate almost closes with a few thou clearance. It was jamming every time I closed the throttle.

Hoses were broken everywhere.

The upper intake manifold was full of junk, brown gloopy crud, that was probably dislodging and being sucked into the engine when it wanted to. This was on top of new heads and a clean lower intake.

Now, this poor old widow I bought the truck from for $1K was really screwed by this toyota dealer. To me it looks like they were willing to take her money, but half asKed the job so it would not run correctly. I have put another $350 into all the sensors, gaskets, and hoses to get it correct. Its not yet running, but, This should go back together all cleaned, with garbage parts replaced, and some new sensors. IT should run fine when I am done, but, how could a dealer do this? Another example of great equipment only being as good as your "mechanic".

Shame on the dealer!- Smithfeild Utah!
I'm sure the little old lady was telling them to keep the costs down, but, can you really rebuild an engine with all the old worn out parts?? They may have saved the lady 500 bucks, but cost her the cost of the truck, the engine rebuild, minus my $1K.. Nice guys huh?

 

[mikes4runner]

Dealers suck....... I believe they prey on old people and woman...I don't know how they sleep at night.


Mike

 

[regularguy412]

I'm sure there are 'some' decent dealer repair shops out there. But any time my mom goes in to the dealer, even for warranty work,, I go with her. Can't be too careful, these days.

Please let us know how it goes when you get it back together. Did you pull the VIN and check with your local dealer to see if the headgaskets have been replaced under the recall program? Maybe 'that' was what the dealer was doing in there in the first place . :bash:

Mike in AR

 

[just66horns]

funny symptoms, now gone!

Yup the dealer was in there replacing the headgaskets, but they charged the customer $4K for the priveledge. It looks like they didn't charge toyota for the work, they charged the customer! And then did the work really badly

I have just gotten it back together. Here is what I found.
Three of the five engine temperature sensors were bad.
The BSV ported valve was broken off at the stump and deliberately bypassed. This caused the engine to pull full vacuum on the gas tank, making the vacuum on the gas tank fight the fuel pump.
The intake manifold (upper) was full of carbon build up (lower was clean)
One cam was mistimed by one tooth.
Numerous broken vacuum hoses
Throttle body rotating linkage bent, misadjusted and throttle plate jamming closed.
Engine ignition mistimed by 20+ degrees
Numerous hoses at verge of disintegration (intake manifold heat)
EGR -manifold gasket, only half of it was installed, the inner sealing ring was not there, leaving a massive leak. New gasket fixed it..
And more...

Only a broke 17 year old would have done this. But a dealer did!
The cost for the three sensors, gaskets, hoses at full dealer price (my dealer here in Grand Junction Co) was $350. Labor, about 20 hours for full upper and front tear down and reassemble. But, I am meticulous so I do not have to go back in, a dealer who had down this before should have cut this in half.

The truck runs great now. No problems, drive away from cold, no stutter, stumble, leaks.

Why would the dealer put it together with so many shot/defective components? Again, a car is only as good as its mechanic...

 

[just66horns]

Final check out

Here is a picture from our test of the work! Canyonlands!

 

[just66horns]

Final check out

Here is a picture from our test of the work! Canyonlands!

 

[just66horns]

Final check out

Here is a picture from our test of the work! Canyonlands!