vapour lock?

Need some help with a technical problem - ask away and let's see if we can all help.

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jb
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Re: vapour lock?

Post by jb »

Thanks Will I appreciate it
Good to hear from you
Maybe you are right
The reason I think it might be fuel is that I suspect the pump may have overheated
When I replaced the fuel filter in October it looked like this
... and maybe the in tank one is also blocked
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jb
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Re: vapour lock?

Post by jb »

I took out the in tank filter today and it looks ok
I also inspected the fuel pipes from the tank and they also looked ok and not kinked
Not sure what is next but I will probably renew the distributor cap and rotor arm as everything else electrical is new
I think it must be the CDI+ box - just kidding Jonny

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911hillclimber
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Re: vapour lock?

Post by 911hillclimber »

Indeed, a fine W&D 600 grit rubbed between the contact breaker points might do the trick.
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Nick Moss
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Re: vapour lock?

Post by Nick Moss »

Have all the fuel lines been replaced with hose that is properly resistant to new fuels? Maybe an oldhose is collapsing when hot? Is the fuel pump failing when hot?
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jb
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Re: vapour lock?

Post by jb »

Graham I did wonder if the contacts had closed up when hot.
They were new in the autumn and I set the gap at a nominal 15 thou before adjusting to get the dwell right.
Since they are fairly new do you still think it worth doing the wet and dry treatment?
I looked earlier and the contacts seemed to be ok but everything was disconnected and with an empty fuel tank as I was waiting for the seals so I could not check the dwell angle.
However all is now back together and it even has a little fuel and a new distributor cap and rotor arm so I will try to check the dwell tomorrow.
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jb
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Re: vapour lock?

Post by jb »

Nick I think the pressure side is all new but some of the return lines look a bit older.
The trouble is that I did not do enough checking when it stopped and I cannot remember if I heard the pump or not but as it started ok both times after a cooling off period I assume that the problem is heat related.
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Nick Moss
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Re: vapour lock?

Post by Nick Moss »

I thought I had just stalled but then it would not start. It caught but immediately died each time I tried.
This would lead me to believe it's fuel related rather than ignition
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Jonny Hart
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Re: vapour lock?

Post by Jonny Hart »

Does an early CIS car have a fuel pump relay?
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jb
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Re: vapour lock?

Post by jb »

"The early 911 CIS fuel pump wiring was simple. Turn on the ignition to the Run position and power is immediately supplied to the fuel pump. Not even a fuse got in the way".
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jb
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Re: vapour lock?

Post by jb »

I had the fuel pump pressure and volume tested and all the fuel hoses renewed last week and also changed the air filter so I am hopeful that the problem will not occur again.
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