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kghaas
Joined: 01 May 2017 Posts: 19 Location: Oslo, Norway
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Posted: Sun Mar 21, 2021 5:26 am Post subject: No fuel through injectors |
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Its been a while since I was on here last. Bought a 996tt which has taken the attention, but now I want the 931 up and running.
Been 5 years since it last was on the road.
I now have a fuel issue and hopefully some of you can give me som quick pointers to information or further action. I have read the resurection thread and followed the fuel part.
Car gets fuel to the distributor and it feels like high pressure when I press the fuel feed line. I have not measured it.
When I take the injector out, fuel pump on and press the air meter plate; No fuel.
When I take the injector of, and just have the injector line, fuel comes through but not at any significant pressure.
What should I do next? (I will measure fuel pressure going to fuel distributor, but I am quite sure it is in the 5-6bar range.) _________________ Knut
931 RMCH |
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Rasta Monsta
Joined: 12 Jul 2006 Posts: 11723 Location: PacNW
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Posted: Sun Mar 21, 2021 5:44 am Post subject: |
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Varnished internals in the fuel distributor? _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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anthonimartini
Joined: 17 Feb 2020 Posts: 240 Location: portland oregon
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Posted: Sun Mar 21, 2021 7:27 am Post subject: |
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remove the system pressure relief valve and check the the small o ring on the end of the piston/ spring stack has not failed. when it fails you lose most of the system pressure and likely wont have enough to see fuel flow from the injectors. you also will have very low control pressure so the plunger will lift very easily. hope this is the case as its super easy to remedy. _________________ ive saved alot of 924's
current:
79 MochaSchwartz 931
83 944
87 924S
Instagram @anthoni.jpeg
formerly known as turbellion, lost password. |
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MOTANUL
Joined: 19 Nov 2018 Posts: 214 Location: ROMANIA BUCHAREST
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Posted: Mon Mar 22, 2021 3:10 am Post subject: |
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In most cases it is the electric fuel pump. Even if it is not completely blocked, it can put less pressure than it would be necessary.
Better check the pressure first.
I have 2 old pumps that work but don't have enough pressure.
When new the pump should go 7-8 bar. _________________ 1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979 |
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Mike9311
Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish
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Posted: Mon Mar 22, 2021 9:37 am Post subject: |
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MOTANUL wrote: | In most cases it is the electric fuel pump. Even if it is not completely blocked, it can put less pressure than it would be necessary.
Better check the pressure first.
I have 2 old pumps that work but don't have enough pressure.
When new the pump should go 7-8 bar. |
+1 .... I second this
Just saw Dan's 941 recently have a plugged up fuel pump line _________________ 1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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MikeDanger
Joined: 21 Nov 2002 Posts: 770 Location: Denver
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Posted: Tue Mar 23, 2021 6:19 am Post subject: |
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First dump a gallon of acetone into the tank (this is what most "cleaners are made of, and its much cheaper, Brake cleaner is basically aerosol acetone)
and a bottle of Marvel mystery oil (or 1/2L of ATF)
Install an inline gauge from CIS to WUR (you can make your own homemade set up for a lot less, then a prebuilt, and then install it however you want)
id say let the pump run for enough to cycle the stuff through the system and let sit, then check the next day and see if anything starts flowing. _________________ It was either this or a giant box of legos |
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Rasta Monsta
Joined: 12 Jul 2006 Posts: 11723 Location: PacNW
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Posted: Tue Mar 23, 2021 8:18 am Post subject: |
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I would be extremely cautious with the acetone/ATF mixture. It will penetrate in places you didn't think possible (for example, crimped together fuel pump, crush washers, etc).
I put some in an oil squirt can one time and it leaked out the seams overnight. . .after that I only stored it in glass. _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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MikeDanger
Joined: 21 Nov 2002 Posts: 770 Location: Denver
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Posted: Tue Mar 23, 2021 8:26 am Post subject: |
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Rasta Monsta wrote: | I would be extremely cautious with the acetone/ATF mixture. It will penetrate in places you didn't think possible (for example, crimped together fuel pump, crush washers, etc).
I put some in an oil squirt can one time and it leaked out the seams overnight. . .after that I only stored it in glass. |
Im assuming he still has gas in the tank _________________ It was either this or a giant box of legos |
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