924Board.org

foxtg557 · Joined: 05 Aug 2007 Posts: 99 Location: Hamilton On

1977 (early i believe ) 924

Hi, Im having engine issue's and I believe it's a fuel pressure issue. According to hanes, if i take the fuel return line off, let it run into a measuring cup and run the pump for 30 seconds I should have at the very least 750 cc's of fuel... I did this and I have about 200 - 250 cc's of fuel. I've replaced my fuel filter, im not sure if it's my pump or my accumulator or my fuel distributor. I do get fuel spraying at all 4 injectors but theres still something not right ( Symptom - engine runs good at start, runs for 30 or so seconds and then starts to shutter, cough etc until stalls, then can be started right back up and the exact same thing happens, I have spark, I have air, I have compression but something according to my hanes is not right with my fuel )

I might be pointing a finger at my fuel pump ( I believe I only have the one that is external on the fuel line ) I have tested to make sure that it is running the entire time the engine is running and it still stalls out but while the pump is running it is very loud and might be having issue's not giving enough pressure.

At this point that is my best guess but as I mentioned I'm not sure if it's the pump, accumulator(s), filter, or fuel distributor.

I was also wondering what the specs of the fuel pump are if I were to replace it, how much pressure etc it is suppose to be pumping at.

Thank You
Dave.
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77 924, It Drives !

Ozzie · Posted: Tue Aug 21, 2007 11:06 am Post subject:

Replace the pump. When they buzz a little they are worn and starting to give up.
If its loud its stuffed.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Paul · Posted: Tue Aug 21, 2007 11:44 am Post subject:

Before you replace it make sure the fuel pickup in the tank is not clogged with rust and other gunk.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

foxtg557 · Joined: 05 Aug 2007 Posts: 99 Location: Hamilton On

Perhaps a silly question but...

Paul Said:

Paul · Posted: Tue Aug 21, 2007 1:18 pm Post subject:

Is it possible that someone has installed a fuel filter between the tank and the pump? If so check it. On a stock car, the hose runs directly from the bottom of the tank to the input side of the pump.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Tue Aug 21, 2007 1:24 pm Post subject:

New one here for $252 shipped.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Tue Aug 21, 2007 1:32 pm Post subject:

Another option at your local Parts America/Advance Auto click here for $143.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Ozzie · Posted: Tue Aug 21, 2007 6:19 pm Post subject:

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

It is impossible to do more than throw parts at the CIS unless and until you obtain a fuel pressure gauge and conduct a diagnosis following the procedure as in the Haynes or oem manual.
_________________
John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

Paul · Posted: Wed Aug 22, 2007 11:09 am Post subject:

Ozzie · Posted: Tue Aug 28, 2007 8:14 am Post subject:

was this ever solved?
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Dunno, but there was definitely a damper or silencer as Haynes called it on my 77. The dealer said they didnt have a listing on it so omitted it when replacing the 12mm hose. Pump was noisy before, and a new pump is even noisier still!

Roger

foxtg557 · Joined: 05 Aug 2007 Posts: 99 Location: Hamilton On

The hanes does list a damper for my car, It is there and the replacement new pump is much quieter then the one that I had... my issue was not resolved with the pump, I've followed the fuel line from the tank, damper was removed temporarily to test if that was an issue, it wasn't, then to the pump that was replaced and still problem wasn't resolved... I am assuming the accumulators are working due to the amount of pressure I get after the fuel filter, plenty of pressure there... then goes to fuel distributor which I haven't determined if this is an issue or not... The injectors are okay so the only two things on the fuel line which could be an issue are the fuel distributor and the fuel pressure regulator ( which would be the more likely of the two ) when I find out i'll post a reply...

Thanks to all who have replied.
_________________
77 924, It Drives !

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

mgatlag · Joined: 02 Aug 2007 Posts: 647 Location: Avon, IN

I had the same issues bringing my 77.5 back to life. If you need a new damper, pm me and I can send you one. I have a few extras. I also did have to replace my pressure regulator from the same problems you have. I found one for $150 at Auto Atlanta. When you are testing the pressure, are you lifting on the round disk inside the fuel dist to turn on the pump?
_________________
Michael
'77 1/2 924 N/A- 5 speed Audi box
'04 Ford Taurus - gone!!
'92 Jeep Cherokee Laredo - gone!!

Porsche... better than tea with Miss McGill
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