Engine Ticking only under load

Hi all, I have a strange problem
I have a 2000 2.7 3rz Tacoma that I recently replaced the head on. All went according to plan, but since I got it running, the engine has been making a ticking noise that sounds like lifter tick. Although I know that its not lifter tick due to the fact that the sound is only happening when I am accelerating/when the engine is under load. It does not occur when revving the engine in neutral or when slowing down, downshifting, etc.

The head that I purchased had the valves already adjusted. The truck runs great otherwise. I just wish it didn't tick like it does. Is this a normal sound for these engines?

Has anybody had anything like this? Maybe an exhaust leak on the EGR tube behind the block?

I am stumped

 

might have to set the e-brake and put some blocks under the front tires and have buddy that you trust, really really trust, put her in first or second and slip the clutch while the hood is open and "load" the engine that way so you can isolate the noise... dont go over-board or you will be putting a clutch in it.

 

Take a video of this noise so we can hear it.

 

Could it be engine knock?
Check the knock sensor connection.

 

Tiny exhaust leak (like cracked header, seals not correctly settled etc.) sounds like a "clicking" when you are in the cabin. Obviously under load there is a lot of exhaust gases, way more than under revving in neutral or idle hence the clicking is louder.

 

I thought all tacoma's ticked. Mine is a 2nd gen but if it stops ticking I'm going to start looking for the problem

 

I have a 3.4 and may have the same problem.

 

If you find it let us know where the leak was. I think I also have a similar noise. I even broke down and had a shop try and locate the sound while I outsourced the steering rack bushing replacement but no luck.

-chris

 

Its not the knock sensor. I replaced it recently and i am almost 100% confident that the engine is not knocking.

 

I just got off the phone with King cylinder heads who I got the new head from. Mike who has been helping me out is going to send me some documentation on what the sound could be and steps on head installation. He was explaining to me that there is some kind of a service bolt that needs to be installed before removing the cams to keep tension. I don't remember doing that, so that could also be an issue as well.

ALTHOUGH, I was able to feel a small leak from the EGR tube that connects between the intake manifold and the back of the exhaust manifold. I will try and get that sealed and see if that was the sole source of the sound. Fingers crossed. I dont want to have to dig back into the head to play with the cams......

 

I know that all tacomas and older engines like this normally tick, but mine is so pronounced that it cant be normal. I will post updates as to what I find and my progress. When I have some spare time and a buddy to help, I will try and shoot a video so that you can see the noise I am talking about.

 

Yep, sounds (ha) like an exhaust leak to me too.

 

I hope that that is all it is. I will find out when I get it sealed!

 

One camshaft gear is actually split gear with the spring trying to get teeth apart. The bolt is for keeping these two halves together (locking the spring) when you remove the camshaft. After the camshafts are put back and gears are engaged you remove the bolt. Now the spring keeps both gears engaged with zero slope.

If you skip "the bolt thing" before you remove camshafts the spring will spread gears. In that case before the camshaft is put back, both halves need to be "synchronized" (by turning one half against the other squeezing the spring till "bolt" holes align). If not you will have loose on camshafts and engine will make clacking noise. Also could run like crap if both cams are not opening/closing valves at the same time.

 

I just went out and unbolted the EGR tube on the exhaust manifold to find that I did not install a gasket. The lock ring washers were also pretty worn out. I went and picked up some new ones and just bolted it back on until I can get a hold of a gasket for it. I went and drove around to see if it changed anything, and the noise was much more quiet. I can still feel a small amount of exhaust escaping from the mating surface when I put my finger up to it, I assume a gasket will eliminate that.

My local Toyota dealership has the gasket in stock, but its $20. Gonna shop around and see if any other auto part stores have it for cheaper before I pull the trigger.
Its weird how a small exhaust leak can sound like something mechanical in your engine going awry....

 

Can you take a pic of this location? I know you have a different motor but just curious.

 

Here's a good diy on the 5vz for showing the service bolt and its importance. I know you've got a 4 banger, still the concept should be the same.

 

Thanks for all the replies about the service bolt. That clarifies it.
So, when I took the cams off to install the head bolts, the gear didnt split apart, so that tells me that the bolt was already installed when i got it new, right? Since I didn't know about this bolt when doing the head replacement, I didn't take it out upon reassembly. Should I take the valve cover back off and take the bolt out? It runs great right now, so would it cause any harm to leave it in?


On another note, I was able to eliminate the sound by installing a gasket and putting on new lock ring washers on the EGR tube mounting flange on the exhaust manifold. I got the gasket from Autozone for $3. Waaaay cheaper than from Toyota.
I will take a picture of the tube and where it mounts to so everyone can see what I am talking about.

 

This is on the passenger side of the engine bay. You can see the tube and where it mounts to on the backside of the exhaust manifold. The gasket I got is some type of graphite looking composite. The typical material that is used on exhaust components on all engines. I just dont know what that stuff is called.

 

The service bolt is only to hold the halves of the gears together when the cam is out of the engine. If it's still in there it needs to come out before it backs itself out into your engine and possibly causes damage. Being lubed by engine oil and rotating with inevitable vibrations from the engine running will most likely make that happen in a relatively short amount of time.