RockMtn4Runner

Howdy folks! Short-time lurker and recent registrant here....

So on to the meat of the matter!

I recently bought a 1994 4Runner with a 3.0 V6 with 185K. It ran like caca when I got it. It had an awful ticking under the hood and it idled like a junkie who hadn't had a fix in 3 days. So, I embarked upon a mission to make it run like new. I did the following....

• Ordered the "special" valve adjusting tool and brought all of the valves back in to spec (all 6 exhaust valves where tight ranging from no clearance to .05 inch). I think I got lucky and didn't have any burnt valves.
• Thoroughly douched the plenum, intake, and throttle body with B12. I cleaned the IAC circuit as well.
• Put in new plugs, wires, cap, and rotor.
• Gave the EGR a good douching with the aforementioned B12.
• New plenum and throttle body gaskets (didn't remove the intake)

Well, I fired her up and adjusted the idle to 800rpm and she idles smooth as silk and runs pretty well all things considered. The valve train sounds good (I think). There's just this nagging "tap, tap, tap" that is bugging the hell out of me! It almost sounds like a rod bearing at cold start-up but the sound changes within 10 seconds to a tapping noise (with building oil pressure?). It's like the noise changes as the motor heats up. I was thinking "exhaust leak", but then again I dunno! I guess there is always the possibility that it's a loose wrist pin? At 185K I guess that's a possibility. It almost sounds like it is coming from the bell housing or tranny pan but that could just be a deflection/reflection of the sound? Anyone else out there have a similar experience? I mean the rig runs great now but this sound is making me nuts and I'd like it to be gone if possible without a major engine overhaul!

yoterr

exhaust...at least thats my guess, a rod will knock if you free rev the motor, either it will knock when you hit the gas or when you let off, i had an exhaust leak on my dodge, I SWORE it was a rod, or bad oil pressure, cuz it stoped within 15 20 sec of warm up, but turns out the back two bolts to the manifold were broken

95duktruck

I had a bad ticking sound after I had a rod blow and had the engine rebuilt (it never had a tick before). I got 10K miles before blowing a head gasket. I was pissed cause I spent $3500 to get 10K out of my engine. Waddya gonna do, so I tore it apart myself and replaced the head gaskets now it runs absolutely great (way better than when I paid someone to do it) but the ticking sound remains, just a slight bit quieter. From the research I have done it sounds like its the injectors. They are expensive to replace, I think they are about $190 a piece new. I found that you can get re manufactured ones for a lot less.

I have to replace my knock sensor wire cause of a 52 code that started coming on after I got everything back together (apparently they fail after doing head gasket repairs and are changed no matter what when Toyota does a HG warranty repair).

I am thinking about getting re manufactured injectors to fix the problem once and for all.

I'm no mechanic but that's what I have come up with. I Hope it helps.

toyotatom93

I also have a knock, and like you cant nail down exactly what it is. I think mine is the rod bearings...but could be something else. Basicly I am done sinking money into my motor at this point and going to rebuild once I can afford it, or once it blows up which ever comes first.

But you know these 22re's sound ticky anyway right? It will never run quiet.

95duktruck

The OP's truck and mine are v6 3.0's. The funny thing is mine never had a ticking sound until I got the engine rebuilt, that was at 193K. I think I'm gonna go for replacing the injectors with re manufactured ones. If that doesn't solve the noise it's deeper in the engine which if it is then I'm with you and I'll just wait for whatever it is to blow and figure it out from there.

RockMtn4Runner

Yeah, the thought of a noisy fuel injector has crossed my mind but I don't think that is the case here because of the area the noise is coming from. I could swear it is a rod bearing when I first start the 4runner, but as pointed out by a previous poster a bad rod bearing would be persistent in making the same noise all the time on acceleration/deceleration. My problem noise changes within the first 10-20 seconds of start-up. It graduates from a noise similar to a bad rod bearing to a sharp tapping noise. I am inclined to think I have an exhaust leak. Now it's just a matter of tracking it down... not a fun job on the 3.0 V6 by all appearances. I have heard rumor that the crossover pipe on the 3.0 V6 is somewhat problematic when it comes to exhaust leaks. Can anyone shed any light on that topic? Thanks!

95duktruck

Good info to know.

I found a place in town that will clean my injectors for $20 a piece. If that doesn't solve the problem then I have an exhaust leak as well.

Fun, fun, fun!!!

echdaviem

my 4runner makes that same noise too. it gets quieter after it warms up. i'm thinking it might be piston slap but i not really sure.

Matt90V6SR5

My 3.0 has a constant ticking until it warms u p then it seems to get quietter.Thinking mine might be injectors,motor has 233,000 on it but starts/runs great.Another guy in here told me hes been ticking for 190,000 miles,moral of the story: yotas arent quiet.

TNRabbit

Got video?