I have been having problems with my 3.ol 4runner, got the code 52...finally figured out that it needs to be re-wired to the ecu...but now im not sure i want to waste my time. Recently i noticed a light knock, it only happens when i'm barely on the throttle, not when under full accelleration, or at idle, more after im up to speed and trying to hold it there. I guess what i would like to know is if this sounds like valve knock or rod knock, i should mention that due to the code 52, i advanced the timing on the distributer slightly to combat the lack of power, and i understand that this could be the reason, i just find it odd that it only happens when im lightly on the throttle, goes away when i "give her some". and im starting to think that it could be rod knock. Any tips for figuring this out would be awesome.
Thanks in advance, this site has been real helpfull!!!

 

Retard the timing and see if it goes away. It might be pinging.

 

I don't think it's pinging or knocking because you only hear it at idle (Which you already know). One thing you might want to consider is your belt pulley's. They ususally make a ginding noise when the bearings are going but I just changed my alternator last night, the bearings were bad and when the engine was at idle it made somewhat of a light knocking sound. Anything past idle the noise went away. It could have been easily mistaken for something internal, luckily it wasn't. Hopefully you have the same situation. One thing that I have heard but have NOT tried myself is to drain your oil and fill with gear oil 75w-90. Run for a few minutes at idle and if the noise lessens or go's away then it's definitly internal (bearings, rods, etc.)

Not sure if this helps but I found this...

http://stason.org/TULARC/vehicles/vw...ion-NOISE.html

What causes engine knock/pinging/detonation?
A: Too much advance. Check Timing. Also check VALVE timing. Too low gas
octane/too high engine compression. Engine overheating. Carbon build up on
valves. An improperly torqued knock sensor can cause the sensor to not
function correctly resulting in knock and/or loss of power. Failing knock
sensor.

NOTE: Do not mistake engine knock or pinging for other problems. Knock
occurs under load (e.g., accelerating, going up a hill, fast driving).
Knock seldom occurs under no load conditions (e.g., idle or revving the
engine). If you hear a rattle there <NOISE> it may be something else:
valves, bearing, wristpin slap, etc.

 

$12 spent at Napa may help:

 

Umm you can hear pinging at any rev range and usually with some load applied. Idling is the last place I'd expect a lot of audible pinging.

 

Pinging is usually present under load, hard accelration, hills, towing, etc. This is assuming that everything is working and adjusted properly - timing, EGR, correctly installed timing belt/chain, valve adjustment, etc.

http://www.type2.com/library/engineg/ping.htm

 

Since its an auto I would check the torque convert bolts.

 

Yeah, that was my first thought..Did not help though, maybe i didnt go far enough, but any farther and it would take an hour to get to 60.
It does not ping/knock at all at idle...only when under slight load, full throttle and it goes away, this is why i thought maybe rod knock...excessive wear in bearings.
Thanks for that! I do have code 71(egr), and 52(knock sensor) Maybe these are the cause?The more I think about it, I think it is pinging, sounds like someone put rocks in the combustion chamber and they are rattling around. I do plan to bypass the egr, going to be a b*tch tho cause there is an engine hook that needs to come off, as well as p/s pump... but thats my next project, then re-wire knock sensor, maybe this will fix it? I hope so, cause i dont wanna put any more time or effort into it, if im just going to find out in a month that i have to do a total rebuild!!
Thanks for all your input

 

Only $12...neat...I'm goin to napa first thing in the morning!!

 

Yeah I was able to isolate a ticking at idle to the fan bracket bearing. No tool box should be without one.

 

Yes...very true.. had one that i got from snap-on for somewhere around $200, didnt know there were cheaper alternatives.

 

Wha...? You guys must have money to burn! Ye ol' driver of screws aint n'er let me down!

Seriously though, try it with an extra long screwdriver if you're ever in a pinch. Works almost as well, but leaves you with that warm and fussy feeling of knowing that you didn't overpay 2000% for an average quality tool with a slightly above average warranty.

 

Yeah, see I think it's pinging. I guess check the wiring or replace the knock sensor.

 

yeah..I know the k/s needs to be rewired, just didnt think it could cause this problem as it retards timing, although i guess the fact that i advanced my timing to compensate, that is most likely the issue... and I know the screwdirver trick...done that many a time, its not revealing anything at idle though, and as I understand it, a stethoscope is much more sensitive... would the egr code also be contibuting to this problem?

 

did you ever solve this problem?