troubleshooting 911T ignition

[michaelgrasso77]

Can anyone assist me in trouble shooting a 71 911T ignition sys? Car has been sitting four years and has no spark. I ordered a new set of morelli points which I will install tommorow. Positive side of coil does not get hot when I switch ignition on (blue wire w/ yellow stripe that I assume comes from ignition module mounted on left side of engine bay?) This terminal should become hot, no? Does anyone have a schematic that would be easy for them to send to me so that I may understand the flow of juice from ign. switch to coil? It appears that the juice should come from this ign. module of sorts (I don't really know what it is) Do these units typically go bad after sitting? car ran when stored. How do I troubleshoot? Any input would be greatly appreciated. Thanks in advance
-Michael

[911pcars]

Yes. Ignition coil + terminal should be "hot" (9-12 Volts) with the ignition switch ON.

Here's a page with schematics you can download:

http://members.rennlist.org/911pcars/WiringDiag.htm

Using a voltmeter, check the corresponding wire connection on the back of the ignition switch to verify this circuit and/or switch is okay.

You can temporarily "hot wire" the coil by bypassing the switch. With a jumper wire, connect the coil + terminal to any battery source in the engine compartment. The secondary fuse box is okay. Don't run the coil at full battery voltage too long as the points may overheat.

Hope this helps,
Sherwood

[Early_S_Man]

Michael,

Sherwood may have been thinking of the 1968 and 1969 911T models which had conventional battery-coil ignitions ... but the 1970 and later 911T models came with the same Bosch CDI ignition as the 911E and 911S models! And, no, the coil shouldn't have +12 Volts present at any time!!! Following the points opening ... the coil should get a pulse of +350 Volts to +460 Volts ... of a few micro-seconds duration! An oscilloscope is the best way to view the CDI pulses!

Here is a thread with full Bosch explanation and test procedures for the CDI ignition:

Perma-tune CD or Bosch CD?

If your browser times out before all of the images have loaded, hit refresh! It may require multiple refresh attempts, depending on your connection quality!

The SL35 left and right diagrams on Sherwood's page are appropriate for your car ...

[911pcars]

Michael,
Sorry for the incorrect information, but I hope you found the wiring diagrams helpful.

Warren,
Thanks for the correction.

Sherwood
(gotta sharpen up my reading skills)