123 distributor curve. Please look and comment!

[SunburntLobster]

Hi
Finally connected my usb 123 dizzy to the PC and the curve looks completely different and wrong compared to a normal 2.7 curve?
Car is 1976 911s converted to megasquirt 1, MSD AL6, 123 distributor.
Help!?
Cheers

[snbush67]

It looks like you are at 20 degrees at idle (1000 rpm) and then take a long time to get from 22 to 28 degrees.

Have you verified using a timing light?

[snbush67]

It is wrong. Was it hard to start? At idle it should be closer to 10 degrees BTDC.

[snbush67]

[SunburntLobster]

Yup at cold it requires a light throttle to maintain idle at 900rpm. By time it warms up the idle is nearer 1200rpm.
Also sounds flat and smells a bit!
The dizzy cap and arm are burning out quickly.
I plan to move curve 2 degrees at a time until I end up closer to stock graph and then request local dyno shop to fine tune

[Jonny H]

All three devices are programmable for ignition curve. I would be very careful, there could be curves lurking in the Megasquirt and the MSD box

[rwest]

Originally Posted by SunburntLobster

Yup at cold it requires a light throttle to maintain idle at 900rpm. By time it warms up the idle is nearer 1200rpm.
Also sounds flat and smells a bit!
The dizzy cap and arm are burning out quickly.
I plan to move curve 2 degrees at a time until I end up closer to stock graph and then request local dyno shop to fine tune

This just caught my attention and along with your other post on the car not running- check the rotor for continuity. MSD boxes run very “hot” and many rotors have resistors in them and the MSD will melt the resistor making for no current going through the rotor, which of course means no spark and no start/run.

[icarp]

Originally Posted by rwest

This just caught my attention and along with your other post on the car not running- check the rotor for continuity. MSD boxes run very “hot” and many rotors have resistors in them and the MSD will melt the resistor making for no current going through the rotor, which of course means no spark and no start/run.

rwest, good call
SBL , said he changed the rotor
SBL you should have a 1977 vw golf rotor in the 911

[snbush67]

SBL, like Jonny said you might have ghost curves lurking. I think you should zero out the curves on the MSD and the MS and use the distributor. Set your curve as stock and then check with a timing light to verify.