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Discussion Starter · #1 ·
Hy! explain what happens. my car knocking at high RPM,

was treated:
add more octane.
add premium gas.
change spark plug and cable.
change knock sensor (has a broken cable).
Change the ECU (oh yea, the original has a I/O error when scanned).
add "treatment" to seal any crack in the engine gasket.

Any other recommendation?
 

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sounds like your part replacements were justified. not often i say that.

'adding more octane' or whatever you're up to there is a band-aid fix. not even a fix as you have seen. if its knocking there is an underlying issue, adding better fuel will not solve it. your car is designed to run on the regular stuff. adding premium won't do a thing.

why do you suspect the head gasket? do you have symptoms of this? no there is no additives or treatments to fix this. any additive claiming it will fix ANY leaking gasket is a temporary fix at best and is likely bad for the system you're dumping it in. if you're suspecting a bad head gasket a compression test should be done to confirm.

any other symptoms would be helpful here...so would any error codes from the ECU.

knocking at high RPMs usually indicates that you're not getting enough fuel in there at higher airflow levels. coils are another possibility as they may be functioning partially...but that would present as a misfire, not a knock.

fuel pump may be failing and unable to keep up to higher demands...pressure regulator, even a clogged fuel filter is worth a go.

with supporting ECU codes, there are various sensors that can cause this. TPS, MAP, coolant temp sensor to name a few. all should be tested before replacement unless you like wasting money.

i would not suspect the head gasket in this case...reason is loss of compression does not cause knocking - it causes misfires.

also i would check that this is really knocking and not just some sort of ticking from the engine somewhere. make sure the oil level is right for starters. get someone to rev it up while you listen under the hood, a mechanic's stethoscope will help you find the source of the noise in no time. of course if you have error codes to support the detonation knocking, you can disregard this....but normally the knock sensor is going to tell the ECU to back off which should eliminate the knock, so that makes me a little suspicious.

one example is my old car developed a small pit on the tip of one of the cams. it would start ticking when it was spinning over 5000 rpm. once i found it, turns out it didn't matter. it wore in a way that it wouldn't be harmful to the valve tappet and the cam was not degrading any worse. metal kind of wore into the pit. still worth knowing instead of wondering if you're going to get stranded.

do some digging and get back to us.
 

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Discussion Starter · #3 ·
Thanks for the answer; i see that the "check engine" light not turn even, at start-up (like other light).
 

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Discussion Starter · #4 ·
If i remove the spark cable "1", the motor still running (if i remove the other cable the motor try to turn off).
 

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no that test will prove a lot of nothing. your problem is at higher RPMs and that could cause the car to turn off anyways. if you want to check wires like that get a indicator light.

ECU codes still need to be checked regardless of weather the dummy light is on or not. any past codes will be stored in the ECU. there are some that don't even put the light on first time but will still be stored.
 
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