Just picked up a new to me 2006 v8 limited with 158k miles.
Everything was working fine until I was driving on the highway and lost power, towed home.

Symptoms:

• Engine turns over, however it will not fire.
• Engine started once when I got it home, immediately died and has not started since.
• No DTCs found using OBD2 scanner

What I've tried:

• Replaced fuel filter/pump
• Unplugged fuel line going to engine and confirmed fuel pumping
• Replaced battery.
• Tested Crank Shaft Position Sensor.
• Tested 5/8 spark plugs, all 5 sparked, they were a little wet.
• Visually inspected Timing belt, it seems to be in good shape.
• Dashboard lights currently on: Check Engine (no codes) Battery, A/T Oil TEMP, Oil light. I think these lights may be on because the motor has not started, unsure..
• Tried spare key. Security light for immobilizer does turn off when key inserted.
• Sprayed starting fluid directly into intake, no start.
• Unplugged battery for 30 minutes.
• Tested every fuse.
• Visually inspected all wired.

At this point I'm out of ideas for testing, any help would be appreciated.

I don't know much about the V8's, but did you tear it down to the point where you could inspect the timing marks and see if they were aligned?

To me, it sounds like something happened with the belt to throw timing off.

FWIW, I had a subaru I did head gaksets and a timing belt on and on the crank pulley, there was a line and an arrow for timing marks. I used the arrow instead of the line and was able to crank it and there was spark, but the timing was off because of using the wrong mark. I did what you did, confirmed spark, confirmed fuel, and shot ether right in the intake. Nothing.

After I pulled it apart again and found my error, it ran like a dream.

Hope you're able to find the cause. Keep us posted.

That's a good thought, thank you. I think I'll buy a compression tester. If it has correct compression then I'll tear it down and check the timing marks. I wonder what could cause the timing belt to slip, belt was changed less than 2 years/20k miles ago.

Troubleshooting for an engine that rotates but will not start (source - Haynes Repair Manual - Toyota 4Runner 2003 thru 2009)

1. Is the fuel tank empty?
2. Is the battery discharged?
3. Are the battery terminal connections loose or corroded?
4. Is fuel reaching the fuel injectors (i.e., clogged fuel filter; clogged fuel lines; defective fuel pump; tank vent lines clogged)?
5. Is the cylinder compression low?
6. Is there water in the fuel (or poor quality fuel)?
7. Are the fuel injectors dirty?
8. Are the spark plugs worn, faulty or incorrectly gapped?
9. Is the timing belt broken?

1. Is the fuel tank empty? About 1/4 tank left, confirmed when replacing fuel pump.
2. Is the battery discharged? Replaced with new battery.
3. Are the battery terminal connections loose or corroded? Sanded the terminals to be sure, looks good here.
4. Is fuel reaching the fuel injectors (i.e., clogged fuel filter; clogged fuel lines; defective fuel pump; tank vent lines clogged)? Unplugged the fuel line and turned over once, fuel did come out.
5. Is the cylinder compression low? Added to my list of items to check
6. Is there water in the fuel (or poor quality fuel)? Possible, I'll get some new fuel.
7. Are the fuel injectors dirty? How would I check this?
8. Are the spark plugs worn, faulty or incorrectly gapped? Adding to my list of items to check.
9. Is the timing belt broken? Not that I could see from initial inspection. I'll dig deeper and do a thorough look.

I did spray starting spray into the intake and it did not start. If it was a fuel issue would you expect it to still start with the spray?

Thank you!

Sounds like an timing issue to me, especially with the starting fluid not starting it up. I doubt you’ll lose compression all of a sudden unless you’ve had a catastrophic failure

These threads might be worth a read:

2006 4Runner Engine Shutting Off While Driving

Need Diagnostic Help: Engine died while driving on freeway/ Now won't start

Thank you for these. I'm thinking it's either the timing is off or the Cam sensor is bad/wiring has frayed. Going to take it apart tomorrow. While I'm at it might as well replace the coolant. Anything else I should do while down there?

If your cam sensor is bad, you wouldn't get spark. Or at least you shouldn't. Earlier you mentioned the spark plugs were wet. To me, it really seems like the timing belt. It's getting spark, just at the wrong time.

Also, be sure to change the oil before you fire it up once you do repairs. Last thing that needs to happen is to spin a main bearing because there's too much fuel in the oil.

Thank you. I'll be sure to change the oil. How would I go about checking the timing? If it is off, how would I adjust?

If you're buying something anyway might consider a leak down tester (ideally non-harbor freight). You'll still have compression if your belt slipped but with leakdown if you're at TDC and hear air coming out the tailpipe you'll know timing is off, and can still gauge compression. Does take little more time though. Buddy had a belt slip when a mouse got between the crank and belt

Although wouldn't you get an error code on this engine from the cam and crank sensors being out of sync if belt slipped? I'd think so but don't know either way.

Timing is controlled by the ECU, you can't easily adjust on this or any engine without a distributor.

Timing!! My 2004 skipped 2 teeth when it sucked up a furry critter upon starting. Idled rough, shut off, crank and no start. Smelled rich after trying to start for awhile. Had a shop take a look and they went ahead and replaced the belt and water pump plus tensioners. Darned field mice.

Got everything taken apart today. It looks like the timing did jump see pictures:

I have a couple of questions:

• At this point should I go ahead and change the timing belt? It looks good but has about 20k on it.
• What would cause the timing to jump like this?
• While I have everything taken apart is there anything else I should change? Water pump was done 20k miles ago.
• How do I go about fixing this? Is it a matter of taking the timing belt off and lining the marks up correctly?

Thank you to everyone who has given advice.

I'm new to the 4Runners but I've worked on quite a few Hondas. I think before you make a decision on replacing the belt you might want to inspect and see if there's a smoking gun as to why that belt slipped. It would be a shame to waste the money on replacing such fresh components if they didn't need it.

I'm assuming there's a tensioner of some sort that may have been misadjusted, came loose, or just straight failed. Maybe a critter got in there and decided to make a nest in the wrong spot? I shake my head when I hear stories like this lol.

Pull a spark plug, jam the side of it somewhere that's grounded and see if you have spark. It sounds to me like you lost fire, especially with nothing happening when you hit it with ether.
Possible signal issue, coil issue or something along those lines. Start wiggling wires looking for a loose connection on something.
All engines break down into systems, is it mechanically moving air, is the electrical system firing the plugs, is the fuel system getting fuel to the cylinders.
Sounds like you've eliminated 2 of the three already, concentrate on the electrical and get it making spark is what I'd be doing.