This is my extra dme. Now you have me curious.

http://i475.photobucket.com/albums/r...ps0b4e04cf.jpg

Ops. Too late. I just saw the post. My thought here is to have this one looked over and then plug it in. Leaving the original one in the car. This came out of a donor car for another project. I may send it off at any rate to have it thoroughly inspected for future use.

Bosch 0261210002

Crank Reference/Speed sensor for BMW application. $60 each if you search the web. I have about 6k trouble free miles on a set. -J

Thanks. It looks like the application is an 85 635is. $54 each.

Testing coil is easy.
1. remove '-' wire from coil's '-' terminal
2. turn key to RUN test that you have 12v on the '+' terminal
3. place a spark plug wire from the coil to a test spark plug on the end and ground the test plug. Do NOT go through the distributor, you want just one spark plug hung directly from the coil's hi-voltage output.
4. using a test wire, wire one end to the coils '-' terminal and then ground the other end for no more than 2 seconds, within 2 seconds remove he ground and the plug will fire.

Testing for DME coil pulses requires a simply LED test light. You can get one at Walmart for $5. It must be a a 12vdc LED test light. Then test DME for coil pulses like this:
1. Remove wire from '-' terminal on coil
2. Place test light's '-' to the wire you just disconnected.
3. Place test light's '+' to the coil's '+' post.
4. Crank engine and watch test light, it will flicker as the DME generates coil ground pulses.

Thank you. I will try those.

John

The speed sensor is the main timing device and the reference sensor is required to determine TDC. With an intermittent speed sensor your engine cuts out every time the signal fails. With an intermittent reference sensor you might fare better since it is not always required. It is used to correct timing every once in a while.

Both sensors can fail intermittently with age due to the heat cycling/vibration at the bell housing. Not easy to diagnose since you need to catch the failure "in the act" by having a breakout box with an O-scope. Probably a good idea to replace the sensor when in doubt before embarking on more expensive items.

Ingo

How many cars do you have, John? :)

Ingo and Sal are very well versed in these systems. You're in good hands. Just remembered, I have a new sensor in my toolbox if you need to buy one. Only used for testing.

Tippy,

Too many...

I ended of putting intwo new sensors, the BMW interchangeable one and it fired right up. I took it on a 400 mile drive without a related hitch. I only lost a mirror as if fell of while driving.

Quick question. I just measure the resistance on my reference/speed sensor in my 964. It measures approx 500 ohm. Manual says it should be 960 +/- 96 ohms. The motor fires up and sounds normal. I'm having an issue with the headers glowing (even at idle I see a faint glow). Infrared thermometer shows temps in the 750 range at idle. I've checked most everything trying to narrow down the problem. Would this sensor cause the headers to glow? I'm guessing maybe the ignition timing would be effected by this causing it to run too hot.