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-   -   Unknown "pinging" noise.. (https://www.rx7club.com/1st-generation-specific-1979-1985-18/unknown-pinging-noise-683517/)

Kerebrus 08-27-07 09:03 PM

Unknown "pinging" noise..
 
well this has been going on for quite a while now and im not sure what it is. the easiest answer i've heard is because it's just hot and thats why it happens but i doubt it. also someone said try using premium gas instead of regular but that isn't helpful at all.

basically whats happening is.. when i drive the car after it's either been sitting or if its really cold out, everything is fine. but perhaps it is because of the heat? once the temp level gets to about 1/4 - half way away from cold it starts to do this. if i'm flooring it, or not even flooring but close.. you can hear a loud thumping noise. i'm not sure where it's coming from but some people i've talked to describe it as a pinging noise although it doesnt sound like a ping more like a thump. if anyone has any idea why this might be happening or what i can check out i'd appreciate it.

'84-12A-GSL 08-27-07 09:25 PM

I know with piston engines pinging is a sign of detonation, and with 2-stokes louder pinging means you're running too lean.

Kerebrus 08-27-07 09:33 PM

Well I can tell the car really runs rich, if that has to do with anything. Any ideas what to check or change?

woodonastick 08-27-07 09:59 PM

maybe hot carbon bits? run seafoam and clean your engine... that might help. that stuff does wonders.

Kentetsu 08-27-07 10:51 PM

Could be crossfire... Make sure your plug wires are routed correctly, then check them for any cracking. Take a really close look at the trailing ones. Check cap/rotor too. New spark plugs might be in order, use NGK.

Check the timing, and don't use premium. Use the lowest grade you can find.

Kerebrus 08-27-07 10:59 PM


Originally Posted by Kentetsu (Post 7278258)
Could be crossfire... Make sure your plug wires are routed correctly, then check them for any cracking. Take a really close look at the trailing ones. Check cap/rotor too. New spark plugs might be in order, use NGK.

Check the timing, and don't use premium. Use the lowest grade you can find.

Just put on New cap/rotor and NGK spark plugs and wires about 2-3 months ago so I doubt it's that.

steve84GS TII 08-28-07 12:14 AM

Its not easy to get a non-turbo rotary to detonate unless things are way out of whack.
Make sure the timing is correct first,sounds like the rest of the tune-up related stuff is OK.
Making that noise under full throttle or heavy load, really sounds like engine detonation.
Lean running is a typical cause of detonation,so check your plugs first.If your plugs are black,then you can probably rule out lean running.Going by the exhaust smell isnt a good indicator of mixture on a rotary,since they always smell like raw fuel coming out the tailpipe.
Make sure the timing isnt too advanced and that you run fresh,87 octane fuel.
If it still detonates,then it could be carbon hot-spots,in which case its time to decarbonize the engine with either SeaFoam,water injection or Marvel Mystery Oil/ATF.SeaFoam or water are the best for getting the bathtubs clean since it mixes with the air/fuel mixture and contacts the combustion chambers.The 24hr soaking method using MMO/ATF is better for stuck apex and side seals when an engine has low compression.

Kerebrus 08-28-07 12:26 AM


Originally Posted by steve84GS TII (Post 7278555)
Its not easy to get a non-turbo rotary to detonate unless things are way out of whack.
Make sure the timing is correct first,sounds like the rest of the tune-up related stuff is OK.
Making that noise under full throttle or heavy load, really sounds like engine detonation.
Lean running is a typical cause of detonation,so check your plugs first.If your plugs are black,then you can probably rule out lean running.Going by the exhaust smell isnt a good indicator of mixture on a rotary,since they always smell like raw fuel coming out the tailpipe.
Make sure the timing isnt too advanced and that you run fresh,87 octane fuel.
If it still detonates,then it could be carbon hot-spots,in which case its time to decarbonize the engine with either SeaFoam,water injection or Marvel Mystery Oil/ATF.SeaFoam or water are the best for getting the bathtubs clean since it mixes with the air/fuel mixture and contacts the combustion chambers.The 24hr soaking method using MMO/ATF is better for stuck apex and side seals when an engine has low compression.


Now thats an answer I can give an applause too. Although everyone else had helpful ones as well, i'm going to definitely take this all into consideration and check things out and get back to you. Thanks again


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