Need help troubleshooting 5VZ-FE

I've been lurking around the forums for a while, but this is my first time posting. I have a 2004 Tacoma PreRunner with the 5VZ-FE engine. I am going to give the backstory in case it will help with the troubleshooting.

I was really low on fuel (I know you should not let it get super low, but I was not paying attention for some reason) and was on the way to the gas station. As I was pulling into the gas station I noticed a decent amount of white smoke, but at the moment did not think too much of it. After filling up and cranking the truck, it was idling really low and running rough and there was still a good amount of white smoke. As I drove the truck to the parking lot next to the station to diagnose further, the engine died and I had to coast to a parking spot. I checked the engine codes with my OBD reader and only got one code P2196 which is for 02 sensor being stuck on rich. I had to get a tow truck to bring it home since it would no longer run.

I know white smoke typically means head gasket or cylinder head issues. The truck does have 290k miles, but it was never overheated to my knowledge. My late grandfather owned it before me and he watched out for things like that. I checked the oil and it's not milky.

So basically my questions are:

1. Tips for next steps? I am thinking a leak down test since it won't run to do the simple combustion leak test. I just haven't troubleshot an issue like this before. I'm far from a real mechanic, but I'll attempt about anything with a good guide.
2. If it is something major like a head gasket or cylinder head(s), is it worth fixing on a truck of this age and mileage? I put a little money into fixing it up last year and this is the first major issue the truck has had. Plus it has some sentimental value, but at the end of the day I need a reliable vehicle.

 

A leakdown test would be a good start.

Did you check your fluids?

Low on anything?

Any mixing of fluids?

Did the exhaust smell odd?

Tacoma's hold their value, and would be worth fixing generally speaking.

 

The coolant may be just a tiny bit low, but it's hard to say. All other fluids are normal level.

Oil and coolant both look normal in color and consistency.

I was not able to get a smell of the exhaust since it would not stay running. However I did notice when trying to crank it after the issue started that I was getting a strong fuel smell. But that's likely just because the engine was turning over but not getting a good combustion to burn the fuel.

 

May be just water in the fuel tank.
Fill the coolant expansion tank to the bottom mark and top off the radiator.
When the engine hits operating temp the coolant level in tank should go up, it should go down when engine is cold.
Keep an eye on the coolant level in tank before starting major repairs.

 

These vehicles run forever. You pay for a rebuild and boom 200k miles more. I would sell it as its not a 4x4. But thats me. Deff not junkyard worthy. Just a small hiccup.

 

Thanks for the input so far guys. I will double check the coolant as mentioned and go ahead and order the OTC leak down tester from Amazon since I can't find one to rent at any of the part stores.

 

Ok so life has been rough and I just now got a chance to do the leak down test. I'm hoping someone here can help me make sense of it though.

Cylinder 1 - 71% loss
Cylinder 3 - 76% loss
Cylinder 5 - 60% loss
Cylinder 2 - 78% loss
Cylinder 4 - 64% loss
Cylinder 6 - 76% loss

I tested multiple times to make sure I was at top dead center. I could hear air coming out of the spark plug hole when I was turning the crankshaft so I know I was on the compression stroke before stopping at tdc. While the leak down tester was connected I am pretty sure I could feel a small amount of air coming out of the cylinder next to the one I was testing. I also checked for bubbles in the radiator but I didn't see any. I am having a hard time figuring out exactly where the air is leaking.

Anyway I just can't imagine the odds of both head gaskets failing in the same way. Is that a common thing? It was cold the day it happened so I don't know if the temperature differential could have had anything to do with it. Any opinions, suggestions, and/or next steps would be greatly appreciated.

 

Cyl 5 was the one that failed on mine, I think it may be somewhat common because it runs a bit hotter but not sure. Mine failed to coolant passage but I did not see anything abnormal with coolant or radiator other than slow coolant loss.

It's odd that you could not start the engine though, mine ran OK once the water burned off. I would try to rule out gas contamination before major engine work but not sure how you do that.

The leak down of 60% is low, but you have to find out where the leak is going for it to be meaningful. Did you listen to tailpipe, intake, oil filler cap. Remove PVC valve before checking. If going into coolant I would think coolant level would overflow with rad cap off, or bubbles.

I was just recalling that some throttle bodies (not Toyota) actually had holes open up which let coolant into the intake but never heard of this with Toyota.

Before this happened were you monitoring coolant level? Where is coolant level now in the expansion tank?

Edit - just saw above you say coolant level normal so I would try to rule out gas contamination. With that much white smoke I would think coolant level would be low, the coolant will be leaking well before you see white smoke with a HG or cyl crack because its starts off slow. Was adding coolant to mine for many weeks before I saw white smoke .

Maybe you could remove the fuel filter and pour gas into a clear container. If its gas contamination I would think its something major like vandalism but I don't have experience with this luckily. Perhaps you can pump out the fuel tank from the filler.

Again with only 1 or even 2 cyls down it should be able to start or almost start, not completely dead like you seem to suggest. Mine started easily even to the very end when it poured white smoke out but still ran.

And I would add don't get down about this, how many vehicles will run to 290K w/o major repairs? Not many I assure you and most will be beer cans well before this. And its probably still worth about half of the new price (in running condition of course)!

 

Since all this started when you were low on gas, I'd start by verifying everything in the fuel system first.
When you say you were low on gas, how low? The fuel gauge needle will go below the Empty mark before you are dry (I know because I once went to under half a gallon of gas in the tank, added 17.65gal at the pump to an 18gal tank). If you filled the tank completely, how much was it that you added?

But lets start with the basics so that we can help you troubleshoot:
What happens when you try to start the engine? It turns over and tries to fire? It never fires? It fires a bit and coughs and sputters?
When you first put the key in and turn to Accessory(or whichever is just before turning far enough to crank), the fuel pump should come on - do you hear the fuel pump? It is in the tank, so you may need to have someone listen while you turn the key.
If, as mentioned above, you sucked water or muck from the bottom of your tank, that would explain the sudden rough idle, white smoke, sputtering, and dying.
Have you changed the fuel filter?
Have you checked the fuel pump fuse?

 

Man life has been crazy. I finally just decided to take it to a shop since I have been so busy, but they were backed up so it took a while to back to me. Their diagnostic is pointing to head gasket and/or head. They think its just the passenger side, but need to tear it completely down to know for sure.

Here's where I am struggling. They are quoting $3600 if both heads are ok and can just be resurfaced, $4800 if one head needs to be replaced, and $6000 if both need to be replaced. Are those prices normal? I know everything has gone up, but that still seems like a lot to me.

The truck is a little sentimental to me so I am torn whether to sell it as is, suck it up and pay them to do it, or tow it home and keep it as a project. It would be the biggest repair I've done myself, but from what I have read on the forums and seen on YouTube, I think I can do it. Just looking for some opinions from others that may have had a similar situation.

 

For $6k you might be able to find a rebuilt engine or a low mileage engine to replace.

Where are you located?

 

sounds like you may have a timing issue. If all your leak down reading are close like that it doesnt sound like a head gasket.
that engine does have a timing belt.

 

Sounds like you have another vehicle so DIY possible.
Get a copy of the FSM, I got a CD on bay for a few bucks. Does not have to be your exact year.
Study the section on cyl head removal and you will get an idea of whats involved.

You will need 3/8" and 1/2" drive sockets std and deep and torque wrenches. I bought wobble extensions for first time on this truck and they are must have for hard to access bolts. Angled feeler gauge for checking valve clearance - even if your machine shop does this you want to check.

When removing parts, put bolts etc in labelled ziplock bags and take pictures as necessary.
By the time I had all parts removed, my truck bed was full of parts.

Head removal on the 3.4 is a bit involved since cams have to be removed to get to head bolts.
Key is to understand and follow FSM exactly, sometimes I have to read several times to understand because the wording they use is a bit strange and on mine the pictures are tiny. Combine this with on line info and YouTube.

IMO spending $6k on this truck is too much. Both my heads were OK so its not like every 3.4 has cracked heads.

But would be good to confirm HG, I think since you can't start the engine the only foolproof way is to look for coolant in a cylinder. Pull plug and check plug hole at TDC or use a scope. As I recall there was no coolant in my bad cyl when I pulled head because it probably boiled off or evaporated and my leak was minor but the piston was clean, no carbon on it. But I know coolant in cyl on morning startup because it missed for a few seconds every time. Also my spark plug was really hard to get out, I think the coolant left a lot of residue on the plug.

 

Crazy prices. They sell complete low mileage JDM imported engines for about $1,500 where I live. 6 month warranty. I'd take my chances with a low mileage used engine, before spending $6k for a headgasket job.

I've replaced a 5vz-fe three times now. They are reasonably easy to replace.

 

You can diagnose yourself by looking through the spark plug hole and you’ll see coolant puddled in the chamber
Or it will look wet. Can start for a second to pressurize the cooling system or a coolant pressure leak down test can be done. Look through the spark plug hole before and after. Can test for exhaust gasses in the coolant. Or a compression and leak down test. The 3.4 have a slightly common problem with heads cracking. If it is cracked I’d buy a head from Toyota and just rebuild the top of end if the block is not warped and pistons and walls look good. Or buy a junk yard motor. Yota1 is another place you might want to check out for remanufactured engine or junkyard motor. I personally don’t trust jdm imports or any other reman. Engine.


Seems like all the cracks tend to happen between the exhaust and intake valves in the center of the head I’d check them 1st.

 

https://youtu.be/voLBRDZL9fE this video helped me



https://parts.toyotaofgreenville.com/p/toyota__Tacoma/Engine-Cylinder-Head/62994731/1110169136.html

 

Why so many times? Or for different trucks?

 

Different trucks. I've owned five 3rd gen 4runners. Also I used to part them out.

 

Thank you for the input. Sounds like this is something I can do myself and save at least a couple thousand. Bare minimum it seems like I should tear it down and see how everything looks and decide on repair or engine swap from there. I already have good quality torque wrenches and socket sets so I suppose my time would be worth the savings in this case. I'm going to get it towed back home this week and I can decide to either sell it as it or keep it for a fall/winter project. It's just too hot and humid right now.

If I end up keeping it and doing it myself, is anyone familiar with this kit? Seems like it would make it easy if that's really everything you need and OEM parts.
https://www.yotashop.com/gasket-kit...d-gasket-replacement-kit-2000-2004-kit-1020b/

 

That's a good kit IMO, I used an older version. By memory here's what mine was missing, does not necessarily mean yours is missing also. Unfortunately on some of these kits they don't list all of the included items.

Does not have the injector orings/grommets, only the fuel line washer/oring because they assume you will not remove injectors. However if you want to clean your intake mani runners I would not do it with $1000 worth of injectors on it and anyhow good practice to replace injector orings. FSM says use spindle oil whatever that is but Yotashop says use Vaseline. You will need all injector oring/grommets (I think they have a kit) + the washers if you take apart the front fuel line connector. Good to have xtra fuel line washers anyhow as I dropped one and it was a SOB to find it on top of the transmission!

Exhaust manifold gaskets, also I don't see how you can remove the exhaust Xover w/o removing the down pipe so I would go ahead and get all of the exhaust gaskets, kit comes with the exhaust mani to Xover gaskets.

Comes with a few exhaust mani/Xover nuts. My OEM nuts pretty good shape so optional to get a full set.

I pulled out a couple of the mani to Xover studs - dont do this because I had to have it repaired. If the nut gets stuck, run it back in and spray with penetrating oil until you can get the nut off w/o spinning the stud.

I had a few additional orders to get these misc parts oil the middle of the job and it was annoying.