# Rattling sound when accelerating on GA16



## itp (May 2, 2006)

I have a 1994 Sentra LE. When accelerating, I hear a rattling sound from the engine compartment. It's audible from inside the car and from outside the car. It usually only happens when it's hot outside, or when the car has been idling for 5-10 minutes, and only when the car is moving (so I can't just pop the hood, open the throttle and listen where it's coming from). It's worst when I'm only pushing about 1/3 or less of the way down on the gas pedal; opening the throttle more will usually make it stop. I rarely hear it on the highway. 

I cleaned the TB and IACV, seafoamed the engine and replaced the spark plugs, wires, cap, and rotor (all oem parts, ngk plugs properly gapped). It seemed to go away at first, but when it got hot outside, the noise was still there.

The car accelreates smoothly, runs good, and idles good. What could be causing this?


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## travis_k (Jan 14, 2005)

Sounds like its pinging, what grade gas are you using? Mine pings unless I run 91 octane.
I've got the timing advanced a little too.


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## itp (May 2, 2006)

I use 87, as did the original owner. I tried a tankful of 89 octane on two seperate occaisions, and it made no difference whatsoever. I guess I could try 91 next time.

It's made the sound since I got it last year, but recently it's gotten a little worse; it's also gotten a lot hotter out. My car is 100% stock (unless you'd count a k&n drop-in filter as not-stock).


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## itp (May 2, 2006)

Could it be the catalytic converter?


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## travis_k (Jan 14, 2005)

Mine usually pings unless i use 91 octane gas. I think they are just like that.


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## Rolling_over12 (Jun 29, 2006)

Well I have the same problem with my 1991 I do use 96 Octane fuel  not gonna tell u whenre i get it from well anyhow It isnt the cat I dont have one Im still trying to figure it out I need my timming done that is for sure this might be the problem sigh I dont wanna do it


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## sunnysentra (Jul 24, 2002)

Does it sound like tinking at part throttle on a hill? usually its when the engine is at low speed and you have it in higher gear like 4th and going up a hill, that would do it then. 

My suggestion, you have carbon on the pistons and it builds up over time. I have always used 93 octane in mine and used a product called BG 44K. you can look this up on BG's website. It will clean everything from the tops of the pistons to the valves and combustion chamber. you should not have pinging after that. See carbon builds up over time from improper tuneups and crappy gas, oil burning, short trips. The compression increases with the carbon and using 87 will cause the engine to ping or detonate. that is the carbon glowing red after the burn cycle is completed and then the plug is firing heats up the gas before it should and explosion, thats the ping. 

sorry for the long explanation, use the BG with high octane 93 if you can get it. fill it up and run the tank almost dry to 1/8th tank to get full benefit and really open it up during the process to blow the carbon out. I did this and I saw all kinds of black crap come out. I looked into the spark plug wells with a light and I could read the tops of the pistons with a number stamped. I knew the product worked well. 

Chris 92 classic


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## joeli16 (Nov 19, 2004)

I heard that the heat shield of the exhaust can cause this problem too.You may wanna check it out.


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## Rolling_over12 (Jun 29, 2006)

sunnysentra said:


> Does it sound like tinking at part throttle on a hill? usually its when the engine is at low speed and you have it in higher gear like 4th and going up a hill, that would do it then.
> 
> My suggestion, you have carbon on the pistons and it builds up over time. I have always used 93 octane in mine and used a product called BG 44K. you can look this up on BG's website. It will clean everything from the tops of the pistons to the valves and combustion chamber. you should not have pinging after that. See carbon builds up over time from improper tuneups and crappy gas, oil burning, short trips. The compression increases with the carbon and using 87 will cause the engine to ping or detonate. that is the carbon glowing red after the burn cycle is completed and then the plug is firing heats up the gas before it should and explosion, thats the ping.
> 
> ...


Ive been Using that BG 44k Its not helping I get it from a dealer my dad works at we steal it shall we say but no improvments


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## itp (May 2, 2006)

I switched to 93 octane, and that stopped the pinging. I'll have to look into BG 44k, though.


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## Rolling_over12 (Jun 29, 2006)

lucas upper cylinder Lubercant works great : )


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## itp (May 2, 2006)

Rolling_over12 said:


> lucas upper cylinder Lubercant works great : )


oddly enough, the previous (first) owner dumped a bottle of that stuff in the tank every few thousand miles. the car even came with two in the back seat. *shrug*


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## Rolling_over12 (Jun 29, 2006)

itp said:


> oddly enough, the previous (first) owner dumped a bottle of that stuff in the tank every few thousand miles. the car even came with two in the back seat. *shrug*


took care of mine lol i dunno it is fairly new *shrugs


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## SR20s rule (Feb 19, 2006)

the same thing happened on my 92' XE.

it turned out to be the heatshield on the exhaust, that comes right before the catalytic converter. (i simply just took it off)
and the noise stopped


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## MickeyKnox (Jun 17, 2006)

SR what's the heat shield. is it a metal thing that covers the exhaust manifold under tha car?
I have the same rattling sound after I changed usual bosch spark plugs platinum to 
bosch +2 platinium and played with timing(which is perfect now).
thanks.


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## zac3ne2nr (Jun 30, 2005)

check your ingntion timing. It maybe advanced too high. i found over 12 deg gives you the "rattle" with load / accelerating


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