Will not start when temp is in mid range
 

My 1985 will not start if the temp in in the mid range, after it cools down starts every time. Starts if you pull or push it off. My plan today is to clean all the ground points however, I feel the starter is the root cause. I believe its the original starter.

common issue with our cars, it is usually the solenoid going bad in our original Bosch starters.

Remanufactured Bosch starters don't have a good reputation on this site, the usual replacement is an upgrade to the smaller high torque starters.

There is also a thread on rebuilding the solenoid for your Bosch, if you choose to do a search.

since you think it might be the starter i am guessing the engine does not turn over.

the starters/solenoid are rebuildable. search under my posts for my thread on rebuilding it.
if you can solder, you can bring life back to the solenoid.

even though it sounds like the starter on the surface...
make sure all connections are clean, including grounds. battery to the body, body to the tranny even the battery connection on the starter. make sure the yellow wire has a good clean connection.
dont forget to have the battery checked.

ignition switches can be a problem along with the connector on the relay board

I just did this. Just echoing some of the good advice you've already recieved. Mine ended up being the starter. Check you grounds. You want to rule out any issues with the yellow wire that runs from the ignition switch back to the engine compartment and then to the starter. It's possible with old wiring and poor connections that your issue is wiring and not the starter. The Bentley is a big help checking the wiring as well. Check for voltage drop at the starter. Easier said than done but not that difficult.

My wiring checked out so I ended up with a new Hi Torque starter from our host. Looking through the records on my 86, hot start was a reoccuring theme. Looked like the starter had been out for cleaning more than once but never replaced or properly rebuilt. My understanding is Bosch no longer makes this starter so your options are rebuilt Bosch, new mini-starter from Hi-Torque or rebuilt mini-starter from Fleabay.

400 miles round trip yesterday including several stops of 30 minutes to an hour. Zero start issues when hot.

Good how-to on this in the Tech Info Center on this site.

-J

Same Possible problem with 71 911?
 

Do you think the starter could be the problem on a 71 911? It wont fire when its hot. I have an MSD ignitor.

thanks:confused:

Roper,
I just finished with this exact issue with my 86 Carrera. The engine would not turn over when hot (of course always in front of a bar). I pulled the starter and had it checked and the shop said it was faulty. I reinstalled a remanufactured starter only to find the same problem. When it would not start while hot with the reman starter in I crawled under the car (make sure car in neutral) and had my neighbour turn the key while I tapped the solenoid with a wooden mallet. It instantly started up. I brought back the reman starter and got mine back from the shop and took it to be rebuilt. Reinstalled my rebuilt starter and my problem disappeared.

Will not start when hot
 

Well guys, I've clean all the ground points but I believe I'm going to change out the starter to the high torque one. My wife has inform me that see will not take another trip in the Porsche unless I can assure her that the car will start. Thanks for your input and suggestions.

Not firing with the starter turning and the starter not turning while the engine is warm are two different problems.

The SR68X Bosch starter is a robust unit. It can be rebuilt locally cheaply and if you have a good rebuilder will solve one problem. The other problem of not firing is usally a fuel pressure problem......the fix is dependant on the intake system, Carbs, CIS or Motoronic have differnt fixes.

...and this is one of the major reasons I ponied up for the new Hi-Torque vs. rebuilding the 25 year old Bosch.

J

ETA - Just wanted to add a bit about my recent install. May or may not be of help. If you search previous threads you'll see a lot of mention about the spade connector for the small ignition wire connecting to the starter. On my '86 I found that wire connected to the origninal starter with a ring terminal. I thought about clipping it off and changing over to a spade type connector. Ultimately I was concerned about the robustness of the spade connector and how well it would maintain contact. The male spade onnector on the starter had a hole in it. I drilled this out and tapped it 6-32 (Sorry SAE is what I have). Once mounted it was a straight shot up with a screwdriver to connect the ring terminal with a philips machine screw and star washer. I then backed this with a nut on top. Took a little longer than just crimping on a new spade connector but I don't have to worry about it coming loose.

Starter installation
 

I hope this is the last time I will have to change a starter on a 911. As a 71 year old I have performed, I thought, a number of difficult repair jobs on various vehicles. This one tops them all.

The two things that helped was the information I read on this blog and a flexible camera tool. After cleaning the allen nut with a pick tool, the camera really helped this process, I was able to guide the 10 MM into the nut. I tried to use a universal tool but this didn't work, I was able to use a 6" extension straight to the allen 10 mm with no problems, well some problems, I finally understood what everyone was saying about hugging the transmission. I installed the high torque starter supplied by our host, It would have been helpful to know that the battery cable would have to be rerouted to fit, not a big deal but helpful. I replaced the 10 MM nuts with 17 MM nut with a washer and a lock washer. Tested the starter, no problems.

Thanks again for your suggestion and support.

Then you could solve multiple problems here ... replace the starter but dont tell her you did :)

glad to hear everything went well for you, even though the installation was a PITA. All's well that ends well.