I wonder too;-)? i have still in my 911 an original DME relay Made in West Germany and never ever i had any problems..
ivan

Coming back to this......

The car has a intermittent no-start with the analog relay installed so I think we may be able to rule out relay issues.

I did unplug the relay and re-seat the connector and it re-started so I plan to re-solder all the pins in the connector and take a closer look at the crank position reference sensor.

Will update as I go.

Regarding the pump prime on the solid state relay, the feature is designed to build pressure for quicker starts. Honestly, I can't tell the difference in crank times between the FT9 and factory relay (when the car starts normally (^: )

dtx - sounds like maybe there is a connection and/or ground issue somewhere. I have swapped back and forth with a new DME and the F9 with Prime with no real difference in the past. I have the version with the indicator lights installed with a back up in the glove box. Knock on wood, no issues to date. I had a slow to start issue, but that was resolved by replacing the fuel check valve, FPR and damper. The prime makes the start immediate, not even what I would consider a full one crank cycle - which is great. I have been happy with the F9, but have no comparison of whether it is better.

I've seen several mentions of the BMW sensors. Where does one find these?

BMW Crankshaft Position Sensor
BOS-0261210002

I bought my 85 911 in 1995 and it ran fine for 19 years with the original DME relay. Then one hot day in 2004, it started to die. The car felt like the ignition was turned off for a half a second at random. I replaced it with a new relay from a dealership, and all was fine for years. The German made or Austrian made relays became hard for find and the aftermarket ones were not good at all.

The Solid State relay I bought from Focus 9 has been flawless for many years.

OK, to come back to this one final time! Issue is solved.

I had an intermittent Reference Sensor. The sensors were installed in 2009 when I did the clutch (~7k miles ago)
In 2021, when I did the top-end, I tested both sensors and they checked out.

Fast forward to today and now the Reference Sensor intermittently reads 1kOhm (spec.) and 14MOhms.

The car is running again and it seems to be running smoother with better throttle response. It may be a placebo effect but it does run smoother.

I re-installed the F9 relay and have the mechanical relay as a spare.

Thanks to all the inputs and help guys!

I have the same basic history with mine.

I have a Focus 9 and its been fine.

The crank reference sensors can be tricky. My car had an occasional no-start-when-hot. Would fail 3 times in a row and then be fine for 2k miles! My mech determined one was bad by doing an ohm check when hot. The reading bounced around. Once it cooled down, the reading was fine. The one which failed lasted 6yrs and 20k miles.

The sensors can indeed be flaky. I had one set of them that tested fine when cold, and even hot when I tested them, but the car ran like it was haunted. At idle it would suddenly go to 2,500 RPM and stay there for 30 seconds, and then die like the key was turned off.

I replaced them and bam, the problems were cured. If changing the DME relay does not fix the issue, replace the sensors.

As one gotcha, I had one time the car just would not run right. It turned out to be the original Bosch black coil had started to ooze out tar. I have yet to find a current coil on the market that works right for the 3.2 DME ignition. I managed to find an original 38 year old Bosch black coil, and it is working great. The new Bosch silver coils are just garbage, and a brand new one from the dealership can be non functional, or last a short few days.

I really would like to find a source for a quality coil that is designed for the 3.2 Carrera DME system voltages. The wrong voltage coils can damage the DME itself.

Had my Focus9 relay recently fail. At least it failed permanently on so that the car still ran but the fuel pump would not shut off.
Went back to the standard relay and I just carry a spare.

-Todd

Yes, nothing is as reliable as the original DME relay with less than 5 components, once re-soldered properly.

Focus 9 DME Relay w/Prime
 

I definitely agree about the new coils being garbage. I have a new one sitting on a shelf that worked when it felt like it. Caveat emptor.

I hope someone decides to make a good working new unit one fine day….