still rough
 

OK - set up the test module & only got a continuous 12 volts (actually 11.54v) - no dips to 0.00 so assumed (correctly I hope) that the unit was faulty. A bit puzzled tho since it starts & idles OK most of the time.

Anyway - swapped back to the points. Set new points, added new rotor for good measure. Timing to 5 ATC, idled nicely. Set off on road test - 1st gear good, second strong, third gear ok then splutter. What? Bugger! Limped home.

Only thing in ignition left is coil & plug leads. Running a genuine Bosch black coil. Think the leads are at least 12 years old.

Where to from here? Fuel lines, injectors? A good mechanic???
I just hate being beaten - but I hate being unable to enjoy my 911 even MORE.

Any other ideas before I pick up the phone?

wild guess is that points wear block "broke in" and closed.

then there is the coil.

"-" by Ronin
Red by me.

- combustion ignition voltage demands only what's necessary no matter what the coil is claimed to output.
Never thought about that!

- The MSD works for me and carbs. MSD will also cover up some idle and start deficiencies of a beat engine w/ bad rings, valves etc.
MSD in this case a coil, or the CDI replacement unit?

- imo the best coil for Bosch CD is the old black and expensive Bosch coil. I have an old one in my garage and maybe part number is on it ?
I have the old coil, nothing wrong with it, I just thought a higher voltage coil would be better.

- I use Pertronix 1867 Ignitor to replace points. I have a spare 1867 wired and ready to be screwed into the connector block.
- if moving the Ignitor within the dizzy the ignition timing is affected.
- I use blue loctite to fasten the Ignitor.
- imo all electronics is heat sensitive. Even Ignitor instruction say the Ignitor will be damaged if ignition is left "on" without engine running.
- I've been running the 1867 for 20,000 miles problem free. Even hung around 100-110F deserts with only slow street driving with no problems.
- I rewired whole ignition wiring w/ Ancor marine wire that has tinned copper strands.
- imo, poor wiring connectors or even faston connectors and old stock wiring is a problem waiting to happen.
- Waytek www.waytekwire.com has double wall shrink tube, "Polyolefin Dual Wall", that looks almost stock to encase wire completely.

I think I'll replace the point with the Ignitor and keep the point in the car as a backup.

1] ignition voltage demand fluctuates with load, compression, etc.

2] MSD CD. I use the MSD ss coil because I'm using a MSD CD. I figure it's a package. The ss is mounted off the engine to keep it away from engine heat and vibration. I also use the MSD rubber isolators under the CD and coil. Magnecore ignition wires sells a long coil wire for about $12us from Pelican Parts.


also imo

it's the CD that determines ignition efficency.

911 shops have told me that they've seen MSD CD failures when mounted in the engine compartment. My MSD CD does get hot when ambiant air is over 85F. Hot enough that you can't grab it tight. Many track guys install it in the cabin. I use the marine MSD because i've installed a few of them in small ocean racers and never had one fail on me when mounted in their engine compartments. Ocean racer's engine compartments can get very hot. They also pound the crap out of everything. Jock straps, although not required, do help.

Bosch CD and coil is a great ignition.

again, different strokes.............