Sorry in advance -- 87 non-start

[A8bil]

Hi, I know there are lots of threads touching on my issue, but they all leave me with unanswered questions which I hope to clarify in this thread.

I have a 1987 911 carrera. I took it out of winter hybernation and ran it for a good run up to take a hike. When I came back, it wouldn't start. When I turn the key to start, i can hear the solenoid click, but the engine doesn't turn. Fortunately, I was on a slight hill, so i push started it and it runs perfectly. The battery is near new and strong, so when the condition persisted, I presumed it was a starter. I had a well known west coast specialist replace the OG starter with a Bosch gear reduction starter. It started 2-3x normally, then after a run to the beach, same no start condition returned, and I had to have the car flat-bedded (darn parking lot was flat!)

So, my questions:

In other threads, I've seen people mention the 14-pin connector. Is that something I have on the 87 carrera? If so, where do I find it?

I've seen others mention the "DME relay" but it seems that when it goes bad, it prevents the engine from turning over. I'm not sure it prevents it from cranking. Can anyone confirm? And if I am wrong, where is the DME relay and how do I test it to determine if it is the problem?

Given that the car did not start pre-replacement of the starter, then started several times after replacement before returning to a non-start condition, I"m guessing that this is a current issue where the starter is not getting enough power to turn, pointing to a bad ground at the transmission. When i get a chance I'll try jump the transmission ground to a good chassis ground. Other than that, any ideas?

Thanks in advance.

[911obgyn]

Battery ground strap is another thing to clean, check high resistance will cause starter issues. Clean battery terminals pull battery and clean where the ground meets the body of the car,
You can jump the engine to the body to check ground strap on transmission

[famoroso]

I had a similar issue with my '87. Occasionally, over about six months, I would go to start it, get one click from the starter and then... Nothing. Dash lights were bright, etc. Then, I'd cycle the key and... It would crank and start. This could happen both from a first cold start or a hot start.

Something was rotten in the state of Stuttgart. So, I casually checked various grounds, connections, etc. (I have a pump-prime solid state DME relay that was clearly working everytime I switched the ignition on, so that wasn't the culprit). Everything I checked looked good, and the car always cranked & started on the second try, so I wasn't super diligent about continuing the search for a culprit.

Earlier this year I drove the car to visit my uncle who lives less than fifteen minutes away. Before that drive, I pulled the trickle charger off (or reconnected the battery ground, I forget which, as I use both methods between drives), and the car started the first time and I drove off.

It just so happens that my uncle is a Porsche factory trained master mechanic who had his own shop in Palo Alto for ~35 years. He and I got to talking about the symptoms and he immediately suggested a bad battery. I discounted his opinion as my battery was only a year old, Porsche branded unit. I had checked voltages, including my charging voltage, a few times over the previous six months and all had been good there.

So anyway, he and I went out to my car so he could take a listen while I started it. The car cranked strong (i.e. it didn't sound slow / weak), but after cranking for 5-6 seconds it didn't start. Odd (as this was not the previous one-click failure mode). I cycled the key and cranked it again. This time the starter sounded weak and the cranking visibly (audibly) slowed from when I first turned the key to about 6-8 seconds later. I'll be damned if my one year old battery didn't up and die right in front of my, and my uncle's, eyes. His diagnosis had been correct. I bolted a new AGM Group 42 battery in and haven't had an issue since.

Moral of the story is, if your classic car is going to crap out, have it do so right in front of your master mechanic uncle's eyes. That, and don't assume your battery is good based on age. Confirm it by taking it to your FLAPS and having them load test it.

[A8bil]

thank you Frank. I'm in the Burlingame area...want to have your uncle look over my shoulder? We load tested the battery before swapping out the starter under the KISS theory. It tested out fine. The battery is strong, so I have to imagine there is a resistance in the path to the solenoid, which makes me think ground. The DME relay...would it have any effect on the starter cranking?

[famoroso]

Originally Posted by A8bil

thank you Frank. I'm in the Burlingame area...want to have your uncle look over my shoulder? We load tested the battery before swapping out the starter under the KISS theory. It tested out fine. The battery is strong, so I have to imagine there is a resistance in the path to the solenoid, which makes me think ground. The DME relay...would it have any effect on the starter cranking?

That would be a good idea, but my uncle is in SoCal nowadays.

Is your issue a single click or clicking?

My issue persisted through different DME relays.

Sounds like you need to measure electrical resistance of your starter cable and try jumping the starter directly too.

[A8bil]

Just one click. It feels like the engine is seized, but I know it is not because I can push start it and it runs great. I'll try the ground jump when I have a chance to get it on stands.