1991 Toyota Camry V6 Tapping Noise - Toyota Nation Forum : Toyota Car and Truck Forums

AnimatedMechanic · 01-14-2010, 09:35 PM

I just purchased an 1991 Toyota Camry V6; 81000 miles; auto everything; in excellent cosmetic condition; original paint; no rust, garage kept, etc.... Idles very nicely without a miss, good power, except for an annoying knock

that occurs during acceleration and while utilizing the accelerator to maintain speed. The knock goes away immediately after releasing the accelerator

. Oil is clear & clean. Shifts easily. The sound appears to be emitting from the left cylinder head (forward most). I'm thinking that it may be something with the valves? Any help would sure be appreciated...thanks in advance

!!!

atobe · 01-14-2010, 11:09 PM

you sure it's vavle tap?? there isn't anything you can do cep get them re-shimmed... but just to make sure it's vavle tap and not engine knock.. go easy on the gas for a while and next time put in higher octane fuel.. if it goes away then it's not engine knock.

AnimatedMechanic · 01-15-2010, 12:36 AM

I'm quite sure it's not pre detonation. The knocking occurs with (in gear) and without any load. Sound does not change weather I'm driving on a flat road or going up a hill...it's just so annoying. Timing is set to factory and I am using the highest octane gas available on this island. How would you know if a connecting rod or piston is bad? Could I reshim without removing the camshaft?

***zythr*** · 01-15-2010, 09:14 AM

To answer your last question. You can reshim without removing the camshaft? Did you ask the previous owner if they had checked/adjusted the valves? It is supposed to be done every 60,000 miles

AlmightyCamry777 · 01-15-2010, 11:17 AM

My guess is it is not valve noise. As a general rule valve noise goes tick tick tick it doesnt make a knocking sound - also it would stay constant whether in gear or not, you would hear it at idle exactly the same noise as it makes at speed.
I don't know if this engine has a timing belt or a timing chain, if it has a timing chain i'd suspect that first. 89,000 miles is awfully low for timing chain noise or engine knocks in general, unless someone ran it without oil at some point or just didnt change oil for a long time.

you don;t say whether the knock is loud or not, many camrys make ominous noises from time to time that actually turn out to be harmless. My 02 V6 makes an occasional "clop clop clop" sound at idle that goes away for a while then returns. I've changed the oil every 2500 since i got it with 66,000 on it so i dont worry about it. But your noise could be different since you don't know the cars history - i think i'd try to find the cause of the noise (it could be a belt driven accesory like the p/s pump, the alternator or the a/c compressor).
Then if i couldn't i'd just take it in, maybe even to the dealer, since the mechanics have no doubt seen this problem before and probably know what the noise is.

***zythr*** · 01-15-2010, 12:52 PM

Those are good points. Both the 4 and 6 cylinders had timing belts.

AnimatedMechanic · 01-15-2010, 07:08 PM

Quote:

Originally Posted by AlmightyCamry777

My guess is it is not valve noise. As a general rule valve noise goes tick tick tick it doesn't make a knocking sound - also it would stay constant whether in gear or not, you would hear it at idle exactly the same noise as it makes at speed.
I don't know if this engine has a timing belt or a timing chain, if it has a timing chain I'd suspect that first. 89,000 miles is awfully low for timing chain noise or engine knocks in general, unless someone ran it without oil at some point or just didn't change oil for a long time.

you don;t say whether the knock is loud or not, many Camrys make ominous noises from time to time that actually turn out to be harmless. My 02 V6 makes an occasional "clop clop clop" sound at idle that goes away for a while then returns. I've changed the oil every 2500 since i got it with 66,000 on it so I don't worry about it. But your noise could be different since you don't know the cars history - i think I'd try to find the cause of the noise (it could be a belt driven accessory like the p/s pump, the alternator or the a/c compressor).
Then if i couldn't i'd just take it in, maybe even to the dealer, since the mechanics have no doubt seen this problem before and probably know what the noise is.

Thanks! It definitely is not a ticking sound but a knocking sound that starts ONLY when engine RPM is increased from off idle. The sound gets louder as RPM increases but stops the moment I let off the throttle. Regular rhythm...like something is slapping or hitting against something. I don't have the time to take the valve cover off @ this time d/t my work schedule but want to have some idea of what maybe causing this noise or things to look out for. Now I'm wondering if it could be a conrod or piston problem?

AlmightyCamry777 · 01-16-2010, 10:21 AM

Quote:

Originally Posted by AnimatedMechanic

Thanks! It definitely is not a ticking sound but a knocking sound that starts ONLY when engine RPM is increased from off idle. The sound gets louder as RPM increases but stops the moment I let off the throttle. Regular rhythm...like something is slapping or hitting against something. I... Now I'm wondering if it could be a conrod or piston problem?

Really i don't think it is connecting rod or piston slap, (even though it is hard to tell without hearing it) because if it had these problems, usually the engine would make noise ALL the time, the noise would not go away at idle. I have just a couple other ideas:

- if not a belt driven accesory, the noise could possibly even be something minor such as upper or lower timing belt covers loose, misaligned or the plastic is warped or broken and the pulleys are bashing against them.
-oil pump worn out (you can test it for pressure using a tester through the threaded hole for the dash light sensor in the engine block). Oil pump should put out at least 10 psi for every 1000 rpm i.e. at 3,000 rpm you should have at least 30 psi or up to about 50 psi. If you had low oil pressure a bad oil pump could definitely cause a knock (the idiot light on the dash might never even blink even if oil pressure were low, and is not to be relied upon for diagnostic purposes obviously).

AnimatedMechanic · 01-16-2010, 12:38 PM

Quote:

Originally Posted by AlmightyCamry777

Really i don't think it is connecting rod or piston slap, (even though it is hard to tell without hearing it) because if it had these problems, usually the engine would make noise ALL the time, the noise would not go away at idle. I have just a couple other ideas:

- if not a belt driven accesory, the noise could possibly even be something minor such as upper or lower timing belt covers loose, misaligned or the plastic is warped or broken and the pulleys are bashing against them.
-oil pump worn out (you can test it for pressure using a tester through the threaded hole for the dash light sensor in the engine block). Oil pump should put out at least 10 psi for every 1000 rpm i.e. at 3,000 rpm you should have at least 30 psi or up to about 50 psi. If you had low oil pressure a bad oil pump could definitely cause a knock (the idiot light on the dash might never even blink even if oil pressure were low, and is not to be relied upon for diagnostic purposes obviously).

Thanks for these ideas. I hope that it's just one of these conditions.

AnimatedMechanic · 03-11-2010, 02:34 AM

I just went and listened to the noise again. Is it possible that the fuel injectors could be the problem?

white90dx · 03-11-2010, 01:25 PM

Fuel injectors sound like a light tapping noise. Generally, you can only hear injectors while in the engine bay at idle. Other sounds drown it out after that point.

Have you thought about biting the bullet and taking it to a mechanic for diagnosis?

-Charlie

Molokailiving · 03-12-2010, 01:55 AM

Animatedmechanic...May need to consider professional help in diagnosing this annoying problem the noise is driving me CRAZY!

AlmightyCamry777 · 03-12-2010, 01:53 PM

Quote:

Originally Posted by Molokailiving

Animatedmechanic...May need to consider professional help in diagnosing this annoying problem the noise is driving me CRAZY!

Please post back on what it was...maybe someday they will make it a lot easier to record sounds and video on forums like thos one and eliminate a lot of guesswork.

Molokailiving · 03-12-2010, 02:05 PM

Animatedmechanic is actually my son...and yes that knocking noise is annoying. He's leaving for Washington DC today but I asked if he could video tape; post on Youtube; and hyperlink back to here when he gets back in a week. I personally WAS a mechanic at one time but changed careers 25+ years ago and this has me stumped. I have 2 nephews who are both licensed mechanics living in Honolulu and they both think that it may be a bad shim...but the sound actually seems to be coming from the right side head (closest to firewall). At present I'm thinking of dropping the engine and going from there;(

white90dx · 03-15-2010, 05:35 PM

If you think it might be a valve issue on the front head, it is quite easy to pull that valve cover and check the clearance on them. Don't pull the motor unless you have to (I'd even check/adjust the valves on the rear head in the car...)

Any chance that the sound is a mechanical interferance (exhaust, etc.)?

-Charlie