Why would my starter do this???

artisticent · 03-16-2007, 07:42 AM

I have a 77 911 that start every time. However lately i may drive somewhere, stop the car, come back in a few mins and the starter wont turn over at all. I had to push start the car. Once this happened, I drove it home and parked it. I turned the car off and then tried to turn it right back on and again I got no turning over, so I left it figuring the starter is out but I left it a day in the exact same spot and it started right up.
WHats the prob here?? Keep in mind my battery is fine and when key is fully turned I hear fuel pump on, lights. It really is connected to the wiring or the starter. The thing that confuses me is parking the car and it not working at all, and then working the next day without the car being touched in any way.
Any help
Thanks
Nathan

Gasman59 · Gasman59's Garage

Nathan:
When I was in college I had an old BMW that acted the same way. It was accessable from up top so for about a year I wacked the solenoid with a hammer and it worked.
The gas station folks always had a nice laugh over this.
Might be the solenoid sticking when hot.
Ron Y

artisticent · 03-16-2007, 07:51 AM

I ahd to do that with my chevy truck too. But if you are just driving your car after 20 mins or so, why would the starter be hot?? Im sure thats got to be the problem but i want to make sure its not anything else related to the starting system.
thanks
Nathan

angelny911 · 03-16-2007, 09:53 AM

had the same problem on my porsche ,took starter apart and found one of the wires in the solenoid just bearely touching so if i hit a good bump the wire would pull away from making contact solderedit back on never had a problem again

dependencies · 03-16-2007, 11:43 AM

Mines done this about once for every year of ownership
and about as frequently,

either a very brief tow-start

(or as I found out)
merely rocking it in First gear by myself is enough to correct it

eapcpa · 03-16-2007, 12:01 PM

Appears you may have a dirty connection at the battery positive or negative, a poor connection to ground, a poor positive connection at the starter soilenoid, or worn starter. The problem reveals itself due to heat (heat soak). Bad connections get hot due to high resistance which makes it worse and starters are subjected to heat soak when they sit after shutting down. That is why the next day after everything is cool, it starts.

Vintage911Racer · 03-16-2007, 12:06 PM

Check the wires on the solenoid. Make sure they are securely on there. Then Clean the ground wires on the Battery and the engine ground and the trasnmission ground stap. If the above does not solve the problem you may need a new solenoid, or a hot start kit.

Or jsut make sure you always park on the downhill side of any street. Pop it in 2nd or 3rd gear. Not first.

John Brandt · 03-16-2007, 12:16 PM

replace the ground strap

teenerted1 · 03-16-2007, 02:33 PM

i would guess either solinoid or ground.

just had a simular issue this weekend in my teener. usually a fuel pump issue not the starter. but the exact thing you describe happend to me. was the main relay, for me. pulled it off and reconected and was fine. no more issues this week. not sure if 911 are the same but you might check your relays?

VFR750 · 03-16-2007, 02:39 PM

Same problem during a road trip. After I got back I replaced the starter and it never happened again.

cab83_750 · 03-16-2007, 03:59 PM

This was discussed many many times.

Anyway, this was actually my first Porsche issue. All I had to do was replace the ground strap, replace the factory starter with a High-Torque starter, and it never recurred again...........ever!

Good luck!

stevej37 · 03-16-2007, 04:40 PM

Is it possible that the problem might be in the the ignition key switch? Mine has been giving me problems lately...but eventually after turning the key a few times, it starts.

oneblueyedog · oneblueyedog's Garage

It's time for the yellow wire lore to rise up from the archives like a Phoenix.

Get a Hi torque after you try all of the free stuff posted. I replaced every part and cleaned all of the components related to the circuit. Yes even the ignition key switch after turning it off and on 2 to 5 times a try. It's the Bosch starter. It only lasts 27 years. This was after a rebuilt one and 2 new solenoids. Live with the Asian sound of starting excellence. The ridicule you will indure with your Porsche friends will not matter since it will crank every time unless you leave the lights on overnight.

Joe Bob · Joe Bob's Garage

It does it to just pissya off....usually it's old dry grease in the solenoid. Sometimes it's the ignition switch. If the BFH treatment on the solenoid frees it up...it ain't the switch.

ischmitz · ischmitz's Garage

First, a hot engine is harder to turn over. Second, a hot starter has less efficiency and last, a dirty contact in the solenoid accentuates the problem due to a slight voltage loss. Maybe it's time the for the high-torque starter that our host sells....

Rouxzy · 03-17-2007, 01:40 AM

The exact same thing happened to my '77. Checked the ground straps - replaced them. Checked the battery - replaced it. Checked the ignition - replaced it along with a hot start solenoid. I check everything that everyone here has mentioned. Finally I broke down and pulled the starter. The solenoid was never sealed properly and had corosion all through it. Seeing that the starter was almost 30 years old I just replaced it with a high torque starter and ALL problems went away. Good Luck.
Tom

Quicksilver · 03-17-2007, 02:11 AM

It commonly happens with older starters on any car that has a solenoid that physically engages the starter gear. It can be wiring related, switch related, etc... But usually all of the other reasons come back to the fact that as the grease on the solenoid plunger and mechanism gets old and nasty it takes more omph to get the solenoid to slide and kick off the starter. Because the hardened, dried up grease isn't cooperating, the magnetic field created when you turn the key just isn't enough to get it to slide. Improving the wiring so more juice gets to the solenoid can help. Wacking it with a hammer can obviously get it to move. These are generally just treating the symptoms though. (It never hurts to cleanup the wiring connections though!) The solenoid has to slide to the engaged position before it hits the contacts that actually feeds power into the starter. (There is an add-on starter relay kit that can help keep the contacts in your ignition switch from eroding.)

Cleaning and greasing the solenoid, the actuator that engages the gear, and the shaft the gear slides on will usually bring it back to life. Once you have it moving then it will start to spin. The Porsche solenoids are sealed units so you can't take the extra step of cleaning or rotating the contacts inside the solenoid like you can do with a lot of other cars. I'm not even sure if anyone makes a replacement solenoid. (Why replace the whole starter when it rarely needs more then a new solenoid and/or brushes?)

Oh, and the reason that it can take half an hour or an hour to 'come back to life' is that it takes quite a while for the heat to soak out of the motor into the transmission and starter, and then even more time for it to cool down significantly.

BTW - If you get very far into this I highly recommend the Hi-Tork starter as an upgrade. It is a much more modern design and weighs less.

Quicksilver · 03-17-2007, 03:56 PM

Hey! Someone just posted this in the parts forum...

FS or Trade: High Torque Starter

artisticent · 03-17-2007, 06:21 PM

Ok, here is an update. I just changed the starter with one I had already. After the install the car started right up so I turned it off and back on a few times just to be sure it was good. Everything seems fine. UNTIL I drove to the store, then drove to another store, get in the car and nothing. SAME PROBLEM. So once again I banged on the starter but it still would not start so I push started it. Must be something else. HOW ANNOYING.
Nathan

cab83_750 · 03-17-2007, 07:13 PM

Quote:

Originally posted by artisticent
Ok, here is an update. I just changed the starter with one I had already.
Nathan

How old is the one 'you already have'? I am not certain that buying a brand new high-torque starter would fix your problem, but what you are going thru was same route I went thru. I spent many many frustrating hours fixing my problem. I even bought the stupid 'relay.'; I finally said "I will buy a new starter, and if it did not fix the problem, at least it is new, it is high-torque, and lightweight."

Good luck. I am hoping your issue is a simple fix.