Hello everbody, new member here. This will be my first post.

My wife drives, (the heck out of), a 1994 4Runner with the 3.0 V6. Last Friday she was driving home from work and she started hearing this thumping noise from under the hood. Naturally she did what most women would do, she kept on going. She said all of a sudden the dash lit up and the thumping got louder. So she pulled over at a gas station and popped the hood. She called me and said the fan is in the radiator. The pulley bracket bearing failed. From searching the posts on the site it seams to be a fairly common problem. I got a new bracket, ($200), and replaced it. After I got it back together I started it up and it was making a thumping noise. I traced it to the plastic cover behind the harmonic balancer. I put my hand on it and could feel the thump. I figured it was just stuff from the bearing caught in the bottom spocket or stuck in the belt. I told her it was ok to drive it home, about 20 miles. She called me about half way home and said the thumping stopped. So later on that night I get a phone call at work and she says the engine in the truck just stopped. It turned over fine. My first thought was the timing belt broke cause it was a little chewed up from the bearing pieces. Got it home and took the top cover off and the belt was still there. So I checked the timing between the crank and the two cam sprokets and it was off. Both cam sprockets were at about the 2 o'clock position with the crank at TDC. So I got a new belt and replaced it this weekend. What fun that was. So after three attempts at putting the belt on, rotating the engine twice clockwise and checking the alignment marks, it finally lined up. I put enough of the engine together to start it up. I left the belts and fan off. It knocks big time. To me it doesn't sound like bearings but more of an ignition knock. I haven't kept the engine running long enough to stand in front of the truck to see where it's coming from. I pulled the distributor and turned it a tooth forwards and then backwards and it wouldn't start in either position. I was telling a coworker about this tonight and he said to replace my plug wires. (?) He said he got this info from an old Toyota mech. He said that when the timing belt started to move the distributor was trying to compensate for it and it may of burned up a wire or plug. I told him he was full of beans. Has anybody heard of this??

 

I think he's off-base with that idea.

The problem with timing belts jumping teeth is that it can cause damage to the valve train on some engine designs. What happens is that the valves hit the top of the pistons and get bent. I don't know if the yota V6 has an 'interference' type valvetrain. But it's something to think about.

 

The 3.0 is NOT an interference engine, so you're fine.

My guess, something isn't quite lined up with the cams and things are not working as they should be. I would double and triple check everything with the timing belt are before doing anything else. Changing too many things at a time can make diagnosing an engine problem much more difficult. How sure are you that you got the crank lined up with TDC on the correct stroke? Check to make sure you have the crank at TDC (cylinder 1), then check to make sure the cams are set to TDC, and finally make sure the distributor is pointing at #1...

You could pull the plugs to inspect them for damage, and possibly replace them, but unless they are totally screwed I'd suggest staying with them until things are running (or at least closer to running) again...

 

The first time I lined up the crank with TDC, I pulled the distributor cap off and the rotor was pointing to number 1. But hey, I've been wrong before so I will check it again. Thanks

 

It's worth a check anyway...

Inspect the spark plugs, and reset the ECU (pull the battery or at least pull the EFI fuse) if you haven't already.

Hmm, what else... make sure no plug wires look damaged from the fan mishap, uh I'm not sure what else...