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Fuel pressure
Hey everyone, I’m having an issue with my car jerking at over 4000 RPM. 911sc 1979
I decided to check the fuel system pressure. The control pressure, system pressure, and leak test all showed factory-spec values. However, I noticed something strange: when I closed the valve on the gauge to check system pressure, the pressure went up to 5 bar as it should. But when I opened the valve again to check control pressure, the pressure stayed at 5 bar and didn’t drop as expected. Sometimes the pressure would go back down to normal, but other times it just got stuck at 5 bar. So clearly, something’s not right. Where should I start looking to find the root of this problem? Here’s a video where it’s all shown clearly: http://youtu.be/2qVKN8Gk02M?si=8k7_uk7zEflI9wqF Also there is bubbles in the fuel tank, is it okay? Video: https://youtube.com/shorts/T8IoXqjbWKE?si=nKHJSfC-niXcvmJV
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Arthur. Owns a Porsche 911sc 1979 Sportomatic. |
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06-24-2025, 03:40 AM
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Join Date: Oct 2019
Location: Ottawa
Posts: 723
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A few weeks back at least two members found their fuel pressure gauge to be acting up.
I can't find the posts... sorry. Found one, but there are more recent ones, I'll look again: https://forums.pelicanparts.com/porsche-911-technical-forum/838021-harbor-freight-cis-fuel-pressure-tester-review-2.html
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81 SC. 930/16 (us model) Last edited by ahh911; 06-24-2025 at 04:32 AM.. |
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06-24-2025, 03:44 AM
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Thank you very much!
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Arthur. Owns a Porsche 911sc 1979 Sportomatic. |
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06-24-2025, 04:35 AM
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Location: Ottawa
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No Problem.
Found the recent post I was thinking about: https://forums.pelicanparts.com/porsche-911-technical-forum/1174439-cis-control-system-control-pressure-question.html
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81 SC. 930/16 (us model) |
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06-24-2025, 04:39 AM
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