I'm seeking some wisdom on a ticking sound. My 2006 Rubicon 6speed has a RPM based tick. Slower at idle and speeds up as the RPM goes up. It does not seem to make the sound when I start up in the morning, but it will start ticking after a few minutes of driving. It's not super loud either. I'll hear it at idle, in first gear and then by the time I reach 3rd I can't hear it as the sound of the wind, tires, etc overpower it. If I'm sitting at a light and there's traffic I don't notice it. So yeah, it's pretty quiet and seems to come from the left/driver side of the engine. Get a pen and tap it on a desk, that basically how it sounds.
After a lot of searching I concluded that it could be my injectors, exhaust manifold/header crack, the OPDA, or something valve train related. So I pick up a cheap stethoscope and start poking around. The OPDA wasn't the source (but I will be pulling it ASAP to inspect it). No noticeable tick from poking around the exhaust pipes, but I'm going to check the torque on the manifold bolts just to see. I may pull the manifold to rule out a crack, but from what I gather a small manifold crack will tick at first but the get quiet after it heats up. Not the case here as it never goes away so I'm beginning to doubt that it's exhaust related. I did find that 3 of the four bolts that attach the mini cats to the manifold were slightly loose. Tightened them up and there was very little change, if any at all. The injectors all made a ticking sound when I poked at them. The sound sounded like what I was hearing and matched the speed of the tick. I also heard it somewhat clear in the middle of the starter, but it could have been noise from outside the stethoscope earpiece. I also poked at all of my belt driven accessories and none of them were making the noise.
Yes, I may have just answered my own question, but alas, I am still a young grasshopper. Do the injectors really make that noticeable of a noise? I've seen people say they are noisy but I am 99% confident my 2000 Sahara 4.0 was not making this noise at all (it got stolen 2 months ago). I know these motors are known for making racket, but this tick is causing my OCD to kick in.
Thanks in advance folks!