Hot start problem 82 911sc

[porsche930dude]

I have a problem starting my 82 911 after it is hot and has been sitting for 20+ minutes. Then after it has cooled down its fine and starts easily. When it is hard starting i have to crank it for almost a minute with no reaction at all then it fires right up. I usually give it a break or 2 for a second during this minute and maby pump the gas once or twice. According to pelican parts it is either the fuel accumulator or the fuel pump check valve. I have replaced the check valve and the problem persists. I am a do it yourself kinda guy and i dont have a cis pressure guage to check the fuel psi nor do i know how. Before i spend 120$ on a accumulator i am wondering if anyone else has had this problem that knows what else it could be. Also what exactly does the accumulator do? i cant seem to find a decent write up on it. Thanks in advance

[syncroid]

My first instinct would have been the fuel pump check valve but you said you already replaced that. The fuel accumulater would be the next in line to check, but...you need the gauges for that. The accumulator is a diaphram that gets pushed back when the fuel pump is running. The 82 911SC accumulator held 40cc of gas if I remember correctly. When it is working properly it will keep pressure on the system for a minimum of 20 minutes after the car is shut down. If the diaphram inside it is bad, you won't have any residual pressure to fire the engine. When the engine is cold it does not matter because it uses the cold start injector instead for that initial fire up. A temporary "bandaid" to get you around till you fix it right would be to disconect the rollover switch on the back of the sensor plate.

[ruf-porsche]

Accumulator maintain the fuel pressure in the line after the engine is shut off. This is to prevent gasoline in the line from vaporizing due to the heat from the engine. A bad check valve in the fuel pump or leaky injectors can also cause residual pressure in the fuel line to dissipate quickly.

[tldry]

I had precisely the same problem with my 82. Like you, I first replaced the check valve which didn't solve the problem. Replacing the accumulator did the trick.

[cmonref]

You don't need guages to diagnose a faulty accumulator. In the 20 minutes after engine shutdown, remove the lower fuel line on the accumulator. If gas comes out of the accumulator, the accumulator diaphram is leaking and the accumulator must be replaced.

[porsche930dude]

Originally posted by Brian K. Haggard
You don't need guages to diagnose a faulty accumulator. In the 20 minutes after engine shutdown, remove the lower fuel line on the accumulator. If gas comes out of the accumulator, the accumulator diaphram is leaking and the accumulator must be replaced.

Cool how much gas are we talking about a constant stream or a trickle

[cmonref]

A couple of shot glasses worth of gas is what came out of mine. Not a stream.

[porsche930dude]

so if it is good then just a trickle should come out maby 1 shot glass worth? also this is testing it in the first 20 minutes? not the 20 minutes after that when it wont start, correct? Thanks again very much you guys have been a great help. Im new to these forums and i must say i will be frequenting them often. Here are some pics of my porsche for your enjoyment