I'll first introduce myself before i ask my Tech question.
I'm from the Netherlands and i just bought my first Wrangler. It's a 1999 4.0 TJ with 159.000 kilometers and some mods.
4" inch lift Rubicon Express Superflex suspension kit
Slip yoke eliminator
Offrotec vacuum diff lock
Easylock front diff
here's a picture:
Before this Jeep i drove a 2004 Mitsubishi Evolution VIII
quite a change going from that to a lifted Wrangler lol. But you have to keep things interesting.
I am thoroughly enjoying this car and even though i have it for only a week i think this is what i should have been driving from the start.
There's a few minor issues like the front brakes that need a little maintenance, some cleaning and fresh pads & some small spots on the body that need attention.
There is also one other thing i have been doing a lot of reading up on. Surprise, surprise
Now i have already ruled out the cat, the heatshield & rest of the exhaust (the cat aint there anymore. The exhaust manifold is a aftermarket one with the flex pieces, then a simple downpipe straight to a muffler under the passenger seat, then a higflow cat and a pipe) Today i gun gummed the connection between manifold en downpipe, fixed the last piece attached to the high cat that was loose and firmed up the end pipe connection so it cannot hit against either the shockabsorber or the fueltank.
I felt around the manifold as good as possible if there was anywhere that sooth had leaked out. It's all clean. I checked the manifold studs as good as possible without removing the inlet. Just a thorough look & feel around, with the engine off, and running. And i also thoroughly banged the exhaust to listen for any sounds. But nothing.
Now the (sound) problem i have is the following.
There are no mechanical ticking sounds when iddling, nor are there any when revving the engine manually. There are no such sounds if i rev it with the clutch in or out. However as soon as i start driving and put load on the engine, hey hey. There is a rattle. it is not a pinging or knocking metalic rattle/sound. It is noticable as soon as you give throttle. With light throttle it is hardly noticable, but there. The more throttle the louder the rattling like sound. The best i can do to describe the sound is a cold diesel sound going up and down with the revs.
It's most noticable when cruising at approx. 50-60 km in 3th and then slightly accelerating or cruising along in 5 at 80-90km and then give it some throtle. As soon as you push it hard the rest of the exhaust overrules the sound but it does seem to become less, but dou to the loud exhaust i cant be really sure.
Now, i have done research, and since it is not a metallic sound i for now rule out bearings, also because it is simply not noticable when iddling. If it would be i assume i would hear a ticking sound. Same goes for the valves, there is some slight valve sound, but hardly noticable.
I pulled the plugs and they look good, no signs of either running rich (black) or lean (grey) Just relatively clean and healthy, though i dont know when they have been last replaced,. The plugs are on the to do list anyway (I opt for NGK's? is that a good choice for the 4.0?) so i think it is not Knock either, i only know knock occuring when running high revs and low quality fuel or badly adjusted carburetors, and know it as a soft crisping pinging sound!?
So, after this long story, what do i have left to check (apart from taking of the inlet and very thoroughly check the manifold, but judging from the loudness of the rattle it must be a huge crack i think, but since i cant feel/see anything suspicious i'm at a loss for the moment. Only other thing i can think of at the moment is the timing chain???
Thank you very much in advance for any suggestion