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No fuel through injectors

 
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kghaas  



Joined: 01 May 2017
Posts: 19
Location: Oslo, Norway

PostPosted: Sun Mar 21, 2021 5:26 am    Post subject: No fuel through injectors Reply with quote

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.)
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11556
Location: PacNW

PostPosted: Sun Mar 21, 2021 5:44 am    Post subject: Reply with quote

Varnished internals in the fuel distributor?
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anthonimartini  



Joined: 17 Feb 2020
Posts: 115
Location: portland oregon

PostPosted: Sun Mar 21, 2021 7:27 am    Post subject: Reply with quote

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.
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MOTANUL  



Joined: 19 Nov 2018
Posts: 157
Location: ROMANIA BUCHAREST

PostPosted: Mon Mar 22, 2021 3:10 am    Post subject: Reply with quote

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.
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Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Mar 22, 2021 9:37 am    Post subject: Reply with quote

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
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 23, 2021 6:19 am    Post subject: Reply with quote

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.
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11556
Location: PacNW

PostPosted: Tue Mar 23, 2021 8:18 am    Post subject: Reply with quote

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.
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 23, 2021 8:26 am    Post subject: Reply with quote

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
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