Engine not starting

[Yardy]

Hi, I've 75 911S that was starting with no problem, then it started intermittently on a few tries now I have to leave it for awhile and try again and it would start then it be for a day and so on anyway I took it to the dealship and they told me that it's an old car and that's how they behave, is this true? When I turn the ignition on I can hear something humming in the back but that's it, the lights and everything else is operational and I even try to jump start it even though the the one thing the dealership did was recharge the battery which is new.When I picked it up from the shop it started right up but in the morning it wouldn't start, it did get very cold that night but I went through the entire last winter without any problems.
Please, if anyone that have had any similar experience give me any advice on this matter!
Thank you!!

[Walter_Middie]

Please don't take the car to a dealer. Find an independent mechanic that specializes in Porshce. If you add your location to your profile, we can give you recommendations in your area.

My 1975 starts right up every time. Saying that old cars just do that is a way of getting you to go away.

It could be a low battery, needs a tune up, or the cold start valve is not operating.

[Rexs-911T]

I would guess the humming in the back is your fuel pump sound

[Targalid]

You have come to the right place. Your 75 is a gem! The experts here can walk you through the diagnosis and repair of this fine car. Start by getting Wayne Dempsey's 101 Projects for your Porsche 911, available at this website and then go from there. By spring you will be in the driver's seat, literally and mentally.

[ossiblue]

Your post is a bit unclear to me. When you say your car does not start, do you mean the starter motor is not being activated or do you mean the engine is turning over with the starter motor but is not firing? I ask because you mention not starting (which, to me, sounds like the engine is turning over but not firing) but then talk about other electrical items working and even trying a jump start and a battery recharge.

Whatever the problem, it will be solved with the help here and, contrary to what the dealer said, it is not normal even for such an old car.

Please clarify exactly what the problem is--no activation of the starter or no ignition of the engine, and we can proceed from there.

[al lkosmal]

Can you provide a little more info regarding the symptoms. does it turn over strongly, start and then die.....or does it not turn over at all...or turns over slowly....etc. With a little more info, we can start to help. It is difficult for me to tell, from your description, if you are experiencing a non-start problem that eventually drains your battery..or a low battery problem that won't crank the engine over enough.

If the 75 is the same as the 77, (Rex, jump in here if I'm wrong) the fuel pump is located at the gas tank and the humming will be heard from the front...but sometimes it's hard to tell where it's coming from. Whining from the back could be your CDI unit, which is a good indication that it is working.from the front will be the fuel pump.

regards,
al

PS: I owned a 77S for many years. While everything was sorted properly, it would start right up, in all weather conditions.

[ossiblue]

I'm not Rex, Al, but I do stay an Holiday Inn . On a 75, the fuel pump is mounted over the left rear wheel, unless a PO has moved it.

[Jerome74911S]

My '74 has the fuel pump under the left rear seat. Stock position for that year.