BruceTS

My guess is you burned your valves and your not getting proper compression, the supercharger is notorious for making the engine run lean. Since you ran it out of fuel, it caused an extreme lean out condition.

MTL_4runner

It might have burned the valves, but he said he has over 145 psi in each cylinder, which is very low compression, but that should be enough to fire the motor. I would think a case of burned valves would send the compression down into the double digits, in which case I doubt it would fire properly if at all. Very confusing....

Have you ever removed the negative battery terminal to reset the ECU?
....if not, definately do and then try to start the motor.

The only other thing I can think of in this case would be that the converters are plugged causing the motor to not be able to breathe. If the converters were plugged you might not get any air movement into the cylinders and when the fuel mixture is too rich it won't fire (need air/fuel ratio to burn) despite having spark. You might try disconnecting the exhaust and see if it will fire then. Other than that I am running out of tests for you to try (other than the timing belt).

Just to verify:

Only things left are the exhaust is blocked or the timing (belt) is way off.

GSGALLANT

Have you had a chance to measure the compression in cylinders 1, 3 and 5 yet? If so, how did they compare to 2, 4 and 6? Also, your coil packs are ohm-ing out too high. Are you lucky enough to know somebody else with a 3.4L engine that would let you try their packs out on your truck?

AJatx

New battery is being used because I need a new battery and I thought it would be a good option to check. It has full charge and new battery clamps.

After I check the timing belt, I'll try disconnecting the exhaust. My buddy did mention it as something to check. Hopefully, the last of the storms have gone by.
Too bad I already have couple projects in the garage taking up precious space.

AJatx

One of the bolts for the timing cover fell into the subframe.
Why did the designers use diameters that are barely big enough for bolts to fall in the subframe? The bolt can fall into the subframe from top but it can't be pulled from below (slightly smaller diameter).

The timing belt looks strange.
There are teeth marks on the outside surface of the timing belt which could be caused by heat. There is also some frayed edges.
The middle idler pulley bearing cover was loose when I pulled off the timing cover. It also looks worn out due to heat.

J

AJatx

The timing belt may have slipped. I didn't have time to broke loose the main bolt for the crank pulley, but the marks on the cam pulleys are lined up and the main pulley is no where close to 0 TDC.

If the belt slipped, how? I ordered a new gasket for the idler pulley #2, but is that common? Should I replace the idler pulley #2?

99lspwr

A burnt valve will give you no compression in that cylinder...

MTL_4runner

Ok finally we are getting somewhere. It is not very common so I am not sure how it happened in this case (you might have broken the woodruff key on the crank so check that too), but check and replace the tensioner and idler if necessary when you go to replace the belt (I assume you will since the other one looks heat damaged).

gpcollen1

Main pulley is no where close to TDC, meaning??

You are 180 off or it is a bit off??

My first few timing belt jobs ended up off a tooth and those vehicles started and just ran a bit off - until i fixed it.

SteveO

So, does this mean the heads are non-interferance heads? If the pistons are moving around, out of sync with the valves, indeed it wouldn't start. But if this is a interferance head, wouldn't a valve had crashed through one of the pisions by now?

midiwall

Right. The 3.4L is a non-interference engine.

SteveO

Well, that makes sense how the crank key could break and the engine doesn't completely blow up. Good thing for Ajatx its a non-interferance.

norflaballer

Well i would like to just throw something out there. My buddy ran his truck completely dry and it wouldn't re-crank after hge gassed it back up. Ended up he ran the Injectors dry and they had to pump gas through them b/c the Pump itself would not get the gas through it.

Hope ya get ur truck runnin bro.

--Jared

midiwall

Umm {insert head scratch icon that I can't find}... that would imply that there's some sort of wicking happening when the injectors are wet which helps draw the fuel from the tank.

The normal pressure in our fuel lines is 45-60psi... That's a decent kick. I dunno what ever wicking effect that would be created from wetting the injectors would be greater than that.

Maybe what happened is that the injectors stuck closed when they dried out and soaking them in fuel acted as a solvent thus loosening them up.

AJatx

Yeah, before I tackled the timing belt, I read up on the 3.4L engines being non-interference.

The main crank pulley is about 90 degrees counter clockwise from 0 TDC.

I attached a picture to show how far it's off.

I'm including another picture of the belt. I don't feel like doing this routine again, so I'll replace it with a new belt. Notice the teeth marks on the backside. Up close, it looks like melted rubber patches like race tires.

Also to be on the safe side, I'm going to replace the idler pulley #2.
Apparently the dealership doesn't sell the o-ring for the pulley.
You can see the dried coolant drops near the bearings in the pulley.
I'll probably go the salvage yard for a idler pulley since the dealer wants $94.

MTL_4runner

Not sure I'd do that since you have no idea how long the salvaged one will last. Unless you want to pull it apart again I'd just pay up for a new one. You might try evan over at Northridge Toyota since they have free shipping and kick butt pricing on their OEM parts.

I'd say that was definately your issue, no way it will fire up when that far off. I am curious to see what the crank looks like when you get the crank pulley off. I really would change the tensioner and idler on there especially after seeing the belt burnt like that (that's the first time I have ever seen a timing belt look like that....and it was still intact).

AJatx

I have a small discount (~10%) with the local dealership (better with a parts person I know). So I went ahead and bought a new idler pulley #2 and timing belt.

Timing crank looks fine. The crank slipped through the timing belt as apparent in the marks on the inside of the timing belt. Before changing my timing belt the first time, I tested the tensioner (according to Haynes) and it checked out fine. I'll find out tomorrow if the tensioner is ok. I would imagine these parts don't usually fail.
Hence my interest in the root cause because it could fail again.

Perhaps I didn't have enough tension on the timing belt?

AJatx

Here's the outer seal for the idler pulley #2 missing from the pulley assembly.

The parts guy at the dealership told me they stock the idler #2 pulley because it's an item that gets replaced at a limited frequency. However, they didn't have the tensioner in stock since it is rarely requested.

How do the seals fail or pop out on the idler #2 pulley?

midiwall

Heat, inferior part... But I would bet that it's failure allowed the timing belt enough slack to get it to skip the teeth that you're seeing now. I guess that's a given now though.


Wow you're going through a lot of crap trying to get this to run. Kudos to sticking wiht it - I don't envy you...

AJatx

After assembling everything together and firing it up, the engine started right away and then died (CEL pointed to Idle Control and the connector wasn't seated all the way). After re-seating the idle air control valve, the engine is rock solid at 800rpm.
Everything is running smooth so far.

The failure analysis:
-------------------
Obviously the idler pulley #2 failed. Not exactly sure why it failed, but maybe it's a good idea to replace it during a timing belt replacement. There's a reason why the local dealers stock this part.

The pulley started to develop more friction after the seal fell out since there are no spacers to keep the ball bearings in the proper positions. It's enough to catch on the belt a little to cause the heat spots on the timing belt. At one point, it was good enough to stop the belt while the crank kept spinning. So, the cams stayed synchronized to each other since they are driven by the crank (source) while the crank slipped out of synch.

Prologue:
--------
The failure occurrence is coincidental to running the fuel tank on empty. I knew it had a tad bit more gas since I have run very low on "E" plenty of times.
Anyhow, it is a tedious process but very fulfilling when you resolve the issue.

Thanks for many recommendations and experiences. I took the long route of checking the cheapest stuff, but ultimately it is timing related. It takes longer to logically check everything (spark, fuel, timing, etc).

Rollin' again,
J