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Discussion Starter #1
Guys,

I am trying to understand what and how the ping/detonation/knock sounds like. I know technically it's same thing, just occurs at different times. Basically I hear some kind of ping sound coming from the engine compartment when I drive up the hill. It's not too loud, but you can still hear it. I don't know is possible that I could be hearing this sound from the head (on the engine block), like springs and retainers? I searched forum and didn't find anything that would answer my question. The car I have is 94 Supra TT, Auto with 80mi on it and I used to run 91 octane on it, but then I switched to 93 and it seemed that noise went away a little bit, but still noticeable. Again it only happens when I drive uphill, strait road or downhill no problems what so ever. In order to better under that soud, imagine launching your car (6 speed) from the 2nd gear and slowly releasing the clutch, but not all the way. It's very simular to that sound, but not as loud.

Thanks in advance,
-Vitek
 

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T88 YOU
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depending on the rpm you are going up the hill at, it is potentially normal to experience knock at lower rpms on hills due to the increase in load on the engine.
 

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Vitek said:
Guys,

I am trying to understand what and how the ping/detonation/knock sounds like. I know technically it's same thing, just occurs at different times. Basically I hear some kind of ping sound coming from the engine compartment when I drive up the hill. It's not too loud, but you can still hear it. I don't know is possible that I could be hearing this sound from the head (on the engine block), like springs and retainers? I searched forum and didn't find anything that would answer my question. The car I have is 94 Supra TT, Auto with 80mi on it and I used to run 91 octane on it, but then I switched to 93 and it seemed that noise went away a little bit, but still noticeable. Again it only happens when I drive uphill, strait road or downhill no problems what so ever. In order to better under that soud, imagine launching your car (6 speed) from the 2nd gear and slowly releasing the clutch, but not all the way. It's very simular to that sound, but not as loud.

Thanks in advance,
-Vitek
It sounds like little pebbles rolling around inside the engine. If 93 octane reduced it, its probably knock. Knock is easier to occur up hills because of load on an engine. Just don't rev too much up a hill. Keep your rpm's low.
 

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yeah, that's knock. Knock occurs most commonly at high load, low RPM...just like you're describing as you go up a hill. My advice would be to give the car a complete tune-up if you can afford it.
-spark plugs
-fuel filter
-pcv
-oil change
-radiator flush
-air filter element
-clean/test injectors if you have facilities
-fuel system treatment (prestone is a good brand, or seafoam)
-O2 sensors if you have any reason to suspect they're not performing properly.
-Make sure your TPS and throttle are both calibrated properly.

After that, only use 93 octane in the car. Anything less is making a HUGE compromise in tuning, more than you probably realize. That should be pretty much everything you should do to prevent that low speed/high load knock.

~Tim
 

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Timdog1650 said:
yeah, that's knock. Knock occurs most commonly at high load, low RPM...just like you're describing as you go up a hill. My advice would be to give the car a complete tune-up if you can afford it.
-spark plugs
-fuel filter
-pcv
-oil change
-radiator flush
-air filter element
-clean/test injectors if you have facilities
-fuel system treatment (prestone is a good brand, or seafoam)
-O2 sensors if you have any reason to suspect they're not performing properly.
-Make sure your TPS and throttle are both calibrated properly.

After that, only use 93 octane in the car. Anything less is making a HUGE compromise in tuning, more than you probably realize. That should be pretty much everything you should do to prevent that low speed/high load knock.

~Tim
Good advice there. Too bad for us Cali residents, we are limited to 91 octane. :rolleyes:
 

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Discussion Starter #6 (Edited)
Thanks for the responce guys.

Timdog1650:
Thanks for the detailed list on what may help fix the issue. I did most of those things already, but I haven't checked the TPS and O2 sensors. I will probably try to run some fuel cleaner first and see if I get any results.

What is the best fuel system cleaner? I did some of the searching and I see people talking about BG44K. Is that a good stuff and where can I get it?
If any body has more suggestions or troubleshooting tips feel free to post, they are welcome.

-Vitek
 

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Seafoam is good, Prestone fuel system cleaners are pretty decent as well....they're legit cleaners, not just weak alcohol in a bottle that dries out your gas.
 

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Chevron Techron (or any injector cleaner with Techron) is very good..So is Gumout Regane
 

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Try running an octane booster see if that helps the problem. If it doesn't, try running a tank of high octane unleaded race gas, see if that solves anything.
 
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