Knock knock

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kappa
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Knock knock

Postby kappa » Sun Jul 19, 2015 4:55 pm

I love cheap gas with low octane :fu
Driving the car in italy ... had no problems with knock, always 0.0.
Today filled up the fuel and the driving was interersting:
Car runs at 1500rpm, when I give him only a little gas the engine goes down to 1300rpm. I put the pedal to the metal the rpms goes to 2000-3000 -> ok
If I drove up a mountain I^ve got knocks alway cause constant gas...
So I let the car rolling home without high rpms the knock was 0.

Tommorrow I will try high octane gas and will see.

Is this possible the low octane gas can produce knock ?
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Re: Knock knock

Postby 2001goldGTP » Mon Jul 20, 2015 1:20 am

Yes, run as high of octane as you can. The octane number is a reference to how much the fuel will resist combustion. The higher the better as you will get a better mix before combustion. The lower octane fuel will pre detonate causing knock. The car in US spec isn't supposed to have less than 92 octane and in California I can only get 91. 87 will cause knock under boost.
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Re: Knock knock

Postby kappa » Mon Jul 20, 2015 7:01 am

Yes and I^ve got the P0452 code but no check engine lights .......
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Re: Knock knock

Postby kappa » Mon Jul 20, 2015 10:23 am

Put the Shell V-Power in (100 octane) and after 20 Minutes it was much better, no more knocks ......
But the code is still there (cleaned it before driving)..
What could this be?
Gascap is normal and new.....
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Re: Knock knock

Postby 2001goldGTP » Wed Jul 22, 2015 1:42 am

Fuel tank pressure low voltage p0452. Open the access hatch above the fuel tank and make sure you don't have a broken wire
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Re: Knock knock

Postby kappa » Wed Jul 22, 2015 4:06 am

Yes I did...but no broken wire I can see. Maybe behind the connector somewhere, I must measure the voltage. How many this should be?
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Re: Knock knock

Postby 2001goldGTP » Thu Sep 10, 2015 11:39 am

its usually +/- 5V for signal and 12V for power
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