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924s fuel supply issue?
https://forums.tipec.net/viewtopic.php?f=25&t=12377		 Page 1 of 1
Author:  PaulPSB [ Sun Feb 19, 2012 1:37 pm ]
Post subject:  924s fuel supply issue?
Ok so some of you will be aware that Brian & were forced to remove the fuel tank to cure a leak :roll: and after standing for several months we finally took
a couple of hours this morning to try and get the old girl running again.

We have cut out a section of the fuel supply and return pipes whilst the tank was out and replaced with sections of rubber hose but we've had issues with fuel seeping from the joints. Today after replacing the rubber hose with slightly different diameter tube the car started and was ticking over but fuel was still seeping from the joints between original metal pipe and rubber tube. We have tightened these and stopped the leaks but now the car won't run?

She will start but then dies and cuts out after a couple of seconds? We thought it might be back pressure so removed the fuel filler cap but this doesnt't make any difference.

Any ideas gratefully received

Paul
Author:  A9XXC [ Sun Feb 19, 2012 7:25 pm ]
Post subject:  Re: 924s fuel supply issue?
As the tank has been off could be anything! First thoughts could be the fuel going off, kink in flexy lines, squashing original metal lines with new clips, FPR (try tapping it), vacuum lines pulled off, blocked filter and I'd also try fiddling with the pick up wire connections on the top of the flywheel.
Author:  PaulPSB [ Mon Feb 20, 2012 7:14 pm ]
Post subject:  Re: 924s fuel supply issue?
A9XXC wrote:
As the tank has been off could be anything! First thoughts could be the fuel going off, kink in flexy lines, squashing original metal lines with new clips, FPR (try tapping it), vacuum lines pulled off, blocked filter and I'd also try fiddling with the pick up wire connections on the top of the flywheel.


Thanks for your thoughts.

Fuel is fresh, filter brand new and have checked for kinks in lines etc. Thing is that the car was ticking over without any problem whilst there was still a leak
from the pipes. It's only stopped running after the leak was cured. I think either fuel pump or FPR.

Paul
Author:  Lee 944 [ Mon Feb 20, 2012 7:50 pm ]
Post subject:  Re: 924s fuel supply issue?
Methodically, I would put things back to see if that is the problem? I remember a fuel leak on my 924 between the rubber and metal pipes. I was scared that if I over tightened the clips, I would compress the metal pipe and cause the exact symptoms you are describing. :?
Author:  scm924s [ Thu Feb 23, 2012 7:28 pm ]
Post subject:  Re: 924s fuel supply issue?
Easy enough to put a jumper in place of the DME relay to check that, and connect the pump to an independent 12v battery to see if it runs OK.
Author:  A9XXC [ Fri Feb 24, 2012 12:23 am ]
Post subject:  Re: 924s fuel supply issue?
Where was the leak? I use jubilee clips quite a lot for work and have found several which have crushed the tail.
Author:  peanut [ Fri Feb 24, 2012 10:13 am ]
Post subject:  Re: 924s fuel supply issue?
scm924s wrote:
Easy enough to put a jumper in place of the DME relay to check that, and connect the pump to an independent 12v battery to see if it runs OK.


yep this is what I'd suggest too.

Remove DME relay and connect the socket terminals 30 and 87b and the pump should run continuously even with the ignition off.
(if you want to try and start the car you will also need to connect terminal 87 to 30 and 87b .)


Have you checked the pump fuse ? think its fuse 34 but check the schematic under the fuse/relay cover .

If you ran the pump dry it could be fubar . Make sure that you have at least 4x gallons of fuel in the tank because the pump will have difficulty purging the system and raising pressure after the tank has been emptied or run dry due to lack of 'head pressure'
Author:  John W [ Fri Feb 24, 2012 10:17 am ]
Post subject:  Re: 924s fuel supply issue?
A9XXC wrote:
Where was the leak? I use jubilee clips quite a lot for work and have found several which have crushed the tail.


Shouldn't use anything but proper fuel pipe clips for fuel lines-they are the only type that apply equal sealing pressure all round. Much less likely to crush the pipe. Depending where the new lines are, it may also be possible to use a flaring kit to flare the end of the metal line where it enters the hose-this will also help with sealing.
I would suggest that curing the leak is a coincidence-I don't see any way in which that would stop it running.....
Author:  peanut [ Fri Feb 24, 2012 11:38 am ]
Post subject:  Re: 924s fuel supply issue?
quite right John

. I can understand why owners try to use flexible hose though, to avoid having to remove the petrol tank and buying an expensive pipe from Porsche

Regarding the fuel pump I have twice had an issue with mine not self purging and pressurising the fuel system due to running very low on fuel and leaving the car for a couple of weeks.

The residual fuel pressure drops to virtually nothing and with no head of pressure from the empty tank some old pumps can struggle to self purge and pump properly. The pump's non return valve may possibly aggrevate this
I believe some models were fitted with a small additional pump in the tanks to overcome this ?
Author:  John W [ Fri Feb 24, 2012 11:40 am ]
Post subject:  Re: 924s fuel supply issue?
peanut wrote:
quite right John

. I can understand why owners try to use flexible hose though, to avoid having to remove the petrol tank and buying an expensive pipe from Porsche


Absolutely agree-if mine ever need doing, it will be using fuel hose.
Author:  PaulPSB [ Thu Mar 22, 2012 8:44 pm ]
Post subject:  Re: 924s fuel supply issue?
Just thought I would post to confirm that the problem was a blocked fuel pump :roll: Car now running with new fuel pump :D
Author:  peanut [ Thu Mar 22, 2012 8:52 pm ]
Post subject:  Re: 924s fuel supply issue?
thats great news :D
Good to have the feedback on the solution too thanks :wink:
Author:  lindsayhbrown [ Thu Mar 22, 2012 9:55 pm ]
Post subject:  Re: 924s fuel supply issue?
:thumbleft:
Author:  John W [ Fri Mar 23, 2012 7:50 am ]
Post subject:  Re: 924s fuel supply issue?
PaulPSB wrote:
Just thought I would post to confirm that the problem was a blocked fuel pump :roll: Car now running with new fuel pump :D


In-tank pump or external?
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