MSII with EDIS, Timing Fluctuating with SAW disconnected

[qadir03]

MSII is setup with EDIS as ignition control on a 1985 Toyota MR2 Turbo. Car starts and run, however timing doesn't hold steady. Tried unhooked the SAW input and timing still jumps around. The VR sensor SAW and PIP signal wires are all shielded. I've replaced both EDIS module and coil pack, still have no luck. Any advice would be greatly appreciated.

Thanks

[jsmcortina]

This is most unusual. Check your VR sensor gap, that the 36-1 wheel is not damaged and possibly try swapping the VR leads. All the times I have had EDIS on the bench the timing is ROCK solid with SAW unplugged.

James

[Heribert]

In Limp home mode, ie SAW disconncted , EDIS is steady , if all is well.
Pls make sure :
Sensor fastened on to the block and totally stable
VRsensor plug fully inserted and shielded VR wires .Route away from HT leads
0,25µF capacitor between coil pack plus, close to the coil and solid ground
Total HT resistance in each circuit ( ie HT wire +plug) 5-10 kiloohms
i.e resistor plugs and or resistor HT leads
Make sure that the 36-1 tooth wheel is connected solidly to the crankshaft , ie NOT on the vibration damper ring . The vibration damper will oscillate at certain RPMs and distort the VR sensor signal , leading to erratic sparking

Good luck

Heribet