Help! Can't figure out why it's running like this?!

Hey y'all. I have a 1995 4Runner with the 3VZ-E. Love this truck, but there is something that is really bugging me. It idles kinda rough for the first 20 to 30 minutes. Even after the temp gauge says it's warmed up, it still runs like this for a while. Eventually it straightens out and runs super smooth though. I did a full tune up (fuel filter, cap, rotor, plugs, wires, air filter, oil change, cleaned the MAF, and cleaned the throttle body), I have replaced the injectors (previous owner had 3 different types of injectors), and new drive belts but I still can't figure out what is wrong. I know I am either burning coolant, or leaking it slowly (don't see any coolant on the ground though) so I thought I'd run through some checks for the head gasket. My thinking was maybe that as it heats up, the head gasket swells and stops the minor coolant leak into whichever cylinder? Does that even make sense?! There is no excess smoke coming from the tailpipe (just the small amount on a cold morning or the water dripping from condensation on a warmer morning), there is no blow by, and there is no loss of power when it is idling rough. I believe the valves need to be adjusted because I can hear them tapping, but I can't imagine that would cause an issue that doesn't stick around once it's warm? I am getting ready to do the timing belt, but I didn't want to do all that work only to find out that the head gaskets need done. I have attached some videos for you to see what I mean. Planning to start working on it this week and could really use some help. TIA!
https://photos.app.goo.gl/Qaa98xF9cnVqgBji7

 

Well.....I very much doubt this is your issue but it takes 2 seconds: when it's running rough unplug the vac line to the EGR. If the problem improves you're onto something. You could also apply vac to the EGR and it should get even worse.

EGR problems typically won't be temp-dependent like yours so don't hold out TOO much hope

 

Gave this a shot and it didn't change a thing. Even unplugged the electrical connector to the EGR and nothing changed. Could it be that it's bad?? Does this mean my EGR is not actually doing anything?

I should also say that my gauge never gets up to full temp. It always stays here when warmed up. Could this be a stuck open thermostat?

 

If you apply vac to the EGR at idle and idle doesn't suffer (or engine stalls) it's possible the EGR is stuck open already. However the fact that your problem improves once up to temp wouldn't point at EGR 'cause that'd mean it magically closes once warm. Every time.

Applying vac with no change could also mean the valve is stuck closed and you have something else (likely) causing your problem.

I don't know what these engines use for an ECT sensor but I'd test it. Something tells the ECM to adjust mixture at cold start-up.

 

Any codes?

 

Hi:
+1 on codes.
Is the check engine light on?
Do you know how to pull a code using a paper clip? This forum will tell you how, with a search.
The electrical connector at the EGR valve just tells the computer that the exhaust temp. is too hot, and to open the valve by way of vacuum.
This will cool the exhaust down(yes it works that way), and reduce NOX emissions.
If you run the motor for a period of time with this plug off, you will set a code.
If you are convinced that EGR is your problem, triple check the hose routing using the diagram under the hood.
An improperly plugged vacuum hose might turn the valve on constantly, and give similar symptoms.
If you think the valve is broken, remove it from the manifold, plug up the hole it is mounted in, and run the engine that way for a while.
Leave the elec. plug connected, and the exhaust riser connected. None of this is used by the engine during cold start up. See if this changes your symptoms.
The valve ticking could also be the injectors clicking, they make a slightly audible sound.
Valves are adjusted by the use of circular hardened shims. You need a special tool to depress the valve bucket, to remove or replace the shims using a magnet wand
You will also need a decent vernier caliper (Bejing Freight $25.00) since the size marks on your existing shims are long gone.
Using the magnet wand, you can swap existing shims around the motor to get most of the cylinders to spec., but the remainder will have to be new purchase (dealer= much bux), or (dismantler= much less bux).
Don't change the timing belt to diagnose this problem, it has nothing to do with it.
The fact that the temperature gauge gives an indication that is sorta' normal is a plus, those gauges are dog meat, and were put there by Toyota to make you worry.
For about $40.00 you can get a kit from EBay that will tell you if there are exhaust gases in your coolant. If there are, then a leak down test will tell confirm that condition.
Now along with the head gaskets, you can change the timing belt, belt idlers (2), and the coolant pump, and the fan bracket, and the thermostat, and the rear cam plugs (they started to leak 1/2 hour after the car was assembled).
Use only the red Toyota coolant
Much bux time.
Good luck
Art.

 

How do I apply vacuum to the EGR? And if it's not the EGR, what could it be?

I don't have a CEL. Can it still be throwing a code?

No CEL. I have a vague idea on how to pull the codes, but I would have to look it up again to do it right.
I am not convinced it is the EGR, I was simply trying any suggestion before I tear half the motor apart to do the HGs. I am open to other suggestions.
As for the valves, I haven't heard enough of valve ticking compared to injector ticking to know the difference. Was hoping someone would be able to tell from the video, but it's not my biggest concern right now.
I am not changing the timing belt to diagnose anything. I am changing it because the truck has 220+k miles and I see no sticker or designation as to when, or if, it was last changed. For all I know, it could be the original lol. I got the kit to do the pulleys, tensioner, water pump, belt, thermostat, and I got the proper red coolant as well. I just didn't want to do that, and then find out I have to take it all back apart to do the HGs. I'd rather do all the work at once while I have things taken apart.
The reason I mention the temperature gauge is because it used to sit right in the middle when I got the truck in March. The heat also used to work. Now it sits low like that and the heat doesn't get hot. This is why I question if it could be the thermostat? That I'm also not super worried about since I will be changing it when I do the timing belt.
What is a leak down test?

 

Since your temp gauge is reading low, and it normally is in the middle and your have no heat, the thermostat is probably stuck open. The first thing I would do is replace the thermostat. There are two coolant temp sensors, one for the gauge and one that sends a signal to the ECM that the engine is up to operating temp. Get the engine up to operating temp and see how it runs.
Even though the CEL is not on, there could be stored codes. Record any stored codes and pull the EFI fuse or disconnect the battery to clear them. You can then check what the new codes are if the CEL comes on.

 

So start by checking the codes, and then clear them to see which ones come back. Then change the thermostat and see if that helps? I'm gonna do the timing belt when I do the thermostat so I don't waste my new coolant.

Thankfully, I do have a Camry to drive in the meantime, so the truck can be down for a while. Does it sound even remotely like a head gasket? Or are there still plenty of things to try before digging in that far?

 

If you have not had a CEL come on or if you have not disconnected the battery since you have owned the truck, there is no telling how long the codes, if any, have been stored. There may not be any stored codes, I would just check before clearing the ECM, in case you get a CEL in the future.

If the engine never warms up, it will never run right. You can drain the antifreeze into a clean container and you can reuse it if you are just changing the thermostat at this time. Or you can do the timing belt maintenance and change everything then.

 

Okay, I will start by seeing if there are any stored codes and go from there.

 

What is a leak down test?[/QUOTE]

Hi:

A leak down test will show the ability of the cylinder being tested to hold an applied pressure for a reasonable length of time.
The reading on the gauge is displayed in real time. Shop air is used to pressurize the cylinder at the TDC to indicate the cylinders holding ability.
This test can help point out gasket leaks into other engine systems.(lubrication galleys, or cooling passages)
A compression test on the other hand stores the highest reading in the gauge itself, while this is good information, it isn't as far ranging as a leak down for diagnose purposes.
Also, the temperature gauge on my 95 4Runner V6 indicates exactly the same as yours does, regardless of the outside temperature. It takes about 4-5 minutes of running to get to that reading.
I think the thermostat is a 190 degree one. I put it in new 11 years ago. The gauge never points elswhere, and there is way enough heat in the cabin if I want it.
You said that you were losing, or using coolant. That should not be happening. Coolant is not a consumable.
I am of the opinion that your first effort should be to test for combustion gasses in the coolant. Use of the dye kit is one way of doing this.
A bad gasket sometimes isn't the only culprit here. A cracked head leak , or bad erosion on the block deck that will destroy a new gasket rapidly, must be considered also.
Sorry if I sound like a doom spreader, but I have run across all of these possibilities in the past, and I has turned me into a realist.
Good Luck.
Art.

 

Z Art T your input is "spot on" glad you aboard 4Runners!

 

No codes being thrown now or previously stored.

 

Hi:

A leak down test will show the ability of the cylinder being tested to hold an applied pressure for a reasonable length of time.
The reading on the gauge is displayed in real time. Shop air is used to pressurize the cylinder at the TDC to indicate the cylinders holding ability.
This test can help point out gasket leaks into other engine systems.(lubrication galleys, or cooling passages)
A compression test on the other hand stores the highest reading in the gauge itself, while this is good information, it isn't as far ranging as a leak down for diagnose purposes.
Also, the temperature gauge on my 95 4Runner V6 indicates exactly the same as yours does, regardless of the outside temperature. It takes about 4-5 minutes of running to get to that reading.
I think the thermostat is a 190 degree one. I put it in new 11 years ago. The gauge never points elswhere, and there is way enough heat in the cabin if I want it.
You said that you were losing, or using coolant. That should not be happening. Coolant is not a consumable.
I am of the opinion that your first effort should be to test for combustion gasses in the coolant. Use of the dye kit is one way of doing this.
A bad gasket sometimes isn't the only culprit here. A cracked head leak , or bad erosion on the block deck that will destroy a new gasket rapidly, must be considered also.
Sorry if I sound like a doom spreader, but I have run across all of these possibilities in the past, and I has turned me into a realist.
Good Luck.
Art.[/QUOTE]
Thank you! I will get a test kit, hopefully tomorrow and see if we have gasses in the coolant. I understand that I should not be losing coolant which is why I know there is something wrong. My question is, why does it stay running normal after 20 minutes? If it were a cracked head or bad erosion on the block, wouldn't it stay running like that? It runs super smooth after 20 minutes.

 

Hi:
There are so many variables that come into play here, that they all can't be covered in a short conversation.
I would venture a guess that after a 15-20 minute period of running has passed, the engine has reached its thermal stability.
The various materials the engine is made of have finished expanding, and have settled into their operating zone.
When this happens, the original cause of the symptom could very well seal up temporarily, and disappear.
When I mentioned erosion on the block deck, I was referring to a piece of block real estate close to cylinder #6.
Due to the design of the V6, as you are probably aware, there is a merge of the 3 passenger side cylinders exhaust heat from the cross pipe,
and the #6 exhaust port heat all concentrated in the rear corner of the driver side head.
Time has shown that this design has played havoc with the head gasket choice that Toyota originally put on these engines.
There is a piece of especially vulnerable block real estate between the fire ring, and a coolant passage opening around #6. (as in the other 5 also).
The H/G will fail in this area because of the excessive heat, and the block surface will erode.
During the Toyota H/G campaign, this particular area was closely inspected for marks and pits, and if it couldn't be rectified by a decking within spec, the block was replaced.
If you are going to do a H/G yourself, you must inspect the block surface thoroughly, especially in the area around #6, and #1 before you do any restoration work to it.
Typically, during a back yard DIY top of the engine refresh, the condition of the block deck is give a cursory look over by an untrained eye, and deemed safe for use.
If there is block damage, putting a new technology multi-layer gasket ($65.00) on a improperly prepared surface is asking for trouble.
I apologize for rambling on, but I wanted to get the seriousness of a properly prepared deck out in the open.

One other point: Stay far away from these JDM replacement engines that are guaranteed to have only 50,000 miles on them.
There is some fairy tale that the Japanese government makes people change out their engines at 50K miles.
That is pure unadulterated BULLXXXX.
Now I'm finished!!!
Good luck.
Art.

 

Thank you. I will try to check for combustion leak this week and post my results. If there is no combustion leak, can the head gasket (or block/head) still be bad?

 

Well gentlemen, the combustion leak test came back negative. That gives me some hope. What's the next test?

 

Hi:
If the engine passes the combustion leak dye test then we have to look elsewhere.
Just for grins pull all 6 plugs, and look at them carefully, in a perfect world they should show an even coloration of a medium to darkish tan color.
If one or more of the plugs looks really clean, like it was hardly used, that could be a tell-tale on the cylinder that it came from that coolant is being combusted along with fuel.
Coolant present in one or more cylinders during combustion, can certainly cause ignition misfires that will show up as lousy running when cold, but better when warm.
The coolant you are losing has gotta be going somewhere.
Are you 100% sure that it is not leaking out while parked over night.
The other possibility is it leaks out while driving because the cooling system is hot and pressurized.
If this is so, then the leak should continue for a while after you shut the engine down, and while there is still heat and pressure in the system.
Look for a staining of coolant color around the engine compartment, near hose clamps, or where the radiator tanks join the core (upper& lower), or around the oil cooler, there could be a clue here.
Also check the oil for contamination of coolant. The oil will take on a light tan coloration, and start to get gloppy if there is coolant present.
Keep us posted.
Good Luck
Art.

If you can, please post a picture of all 6 plugs showing the electrodes, and arranged in the positions they came from.
I am really curious to see their condition.
Art

 

Oil is clean. No coolant there. I will check the plugs later this week and post pictures as asked. The spots I see on the ground are from the slight transmission leak that I have. Everything is so dirty though, it's hard to tell if it is just trans fluid though. Could be coolant dripping down from somewhere in the back and mixing with the trans fluid. I'll have to investigate more. I definitely have seen some grot around the tanks and some of the house connections though. Wouldn't surprise me if there are some small leaks once everything is pressurized. Whatever it is, it's not a fast leak. Maybe I can use some uv dye to find it?

 

I'd say that you should start with a good pressure-wash of the engine.

 

That would probably be a good idea..

 

Hi:

That's encouraging, but not 100% conclusive.
I hope I'm not insulting you, but have you replaced the rad cap. If not, buy an OEM one from the stealership. Not a STANT or other knockoff.
Make sure that the cap seal surface in the rad neck is clean, smooth, and free of schmutz.
Also +1 on the pressure wash.
A test that you could probably get done for a small fee, or even free, at some chain auto stores is a cooling system pressure check.
The test replaces the rad cap with a device that has a sort of bicycle pump and a gauge on it.
It is pumped up to the pressure value of the rad cap, and then observed over a period of time for leak down.
Another way would be to pump each cylinder with shop air when it is at TDC, and observe the rad level for bubbles.
This would have to be done with the thermostat open, or taken out.
A second benefit of the shop air method is that it will show the condition of the rings and valves.
Bad valves will actually show up by listening for a hissing sound at the tail pipe, or throttle body, rings will show as a sound at the oil fill.
If these methods prove out, then I would have to say that the coolant is not being consumed, and is going overboard somehow.
Losing coolant overboard is then probably unrelated to your lousy running when cold symptom.
Oh! as a rule of thumb, also when valves clack a little, it isn't a terrible thing.
Loose is better than too tight. Too tight, and they don't close all the way, burning the seats in a very short period of time.
Loose, and the engine could be down on overall power a little (a 3.0 doesn't have much to spare), but I don't think it would give the symptom you describe.
I'm sorta running out of ideas here.
I just thought of something, do a compression check.
Sometimes a H/G can go bad between two adjacent cylinders, and not into the coolant or oil areas.
This could give a clue towards the lousy running when cold symptom.
Now I'm really all out of ideas.
Keep us posted.
Good Luck
Art.

 

Curious about plugs, too.

Burning coolant can, after enough time, show as crystallization between the electrode and strap

 

No sir! Definitely not insulting me. I will take any advice on things to check at this point. I currently have the entire interior pulled out to deep clean and run acc wires, and I need to get it back together for Saturday. I have a date and I DO NOT want to take her in the falling apart Camry.. I still plan to pull the plugs this week and check there, as well as get a leak down test kit and check to see if the internals are as good as I hope they are. I will forget about the valves for now. I will post pictures of the plugs and results of the leak down and we can go from there

 

I would do a pressure test of the cooling system. Hopefully it’s a small leak at like a hose or something minor. I know it’s easy to assume a blown HG with these rigs lol. Is your 4Runner an automatic? If it shifts into overdrive at the temp you shown I wouldn’t really worry about it running at that temp. I would check the throttle position sensor. When those are out of adjustment or bad, they make your truck run rough. Also the idle air control valve having clogged coolant passages will do the same when cold. You got to remove the throttle body to check/adjust the throttle position sensor, so while it’s off see if you can blow air through the Idle air control coolant passage on the the throttle body to see if it’s clogged. FYI the idle air control valve is built into the throttle body so if it’s clogged, you’ll need to try to clean it out or get a new throttle body

 

Oh and we wanna know how the date goes tonight.....

 

I cleaned the IAC and TB just a few months ago. I know that doesn't rule out the valve simply beating bad though. I have held off on replacing due to the price of TBs lol if it wasn't for the reputation of these 3.turds, I wouldn't have jumped to HG so quickly. Perhaps I have thrown my normal mechanics brain out the window because of that. I did finally find some small coolant leaks that I need to take care of. One is minor at the neck for the radiator cap and another was at my heat control valve. I have bypassed the valve for now until I can get a new one. As for the radiator, where the tanks meet the metal, it's a little crusty so I wouldn't be surprised if the tank seals may be going as well. That will be fixed when I replace the radiator. I'll have to check for other leaks though to confirm.

I'll definitely let y'all know! I figure we will take the truck out and find some snow to get stuck in ‍

 

Right on. Did you check the throttle position sensor? It will make your truck idle and run rough. Mine went out just the other day and I had the same symptoms, as you did in your first post.

 

How do I check it?