Flywheel Sensors on 328

Hi, I'm getting ready to replace the two flywheel sensors on my 87 328, and wanted to ask if anyone out there has done this, and could offer some input (pictures would be nice as well). Also, are both sensors white with a short harness?
Thanks!
Joe D.

 

Yes, two white wires. Located at about 10 oclock & two o'clock on the bell housing . Just a couple of small nuts holds them in place.

 

Thanks Iain. Are they accessable through the wheel well, or better from under the car?

 

I doubt you'd get to them from underneath. Though the wheel well is probably the way to go though you might get to the rear sensor from above.

Speaking of these, I've been meaning to test mine before I put my engine back in.

I found some stuff that you can test these sensors by measuring the resistance across them with 700 ohms being the desired number. Can anyone confirm/deny? Also what is the tolerance? i.e. is 675 or 725 "close enough for government work" or do they need to be dead on 700?

What happens when they get old/start to fail? Does the resistance increase/decrease gradually over time or do they just fail?

 

Iain,the only other way that these can be tested is with the motor running.
To test the RPM sensor,You have to access the microplex unit in the left rear of the trunk(or boot) remove the multipin connector cover to expose the wires.The connector terminals are numbered and at idle with a warm engine, using a multimeter on the AC setting,put the (-) lead on terminal #3 and the (+) lead on #16 it should read >2.0 volts
To test the TDC sensor the same process only put the (-) lead on #2 and the (+) lead on
#1 and it should read >0.2 volts.
As far as the resistance,it needs to be between 600-1000 ohms for both sensors.

 

Maurice, thanks for that - I will just do the static/resistance test for now. My engine was running fine when I took it out so it was just a matter of seeing if there was a quick check I could do (while its very easy to do so) to see if there is an obvious problem brewing.

Maybe I should just look at the cost of replacing the things anyway - presumably they break down over time like most other things electrical?

(#119052 - £38 each inc tax.)

I.