TDC mark jumping around

[timetrialman59]

Hey guys new to this forum but have a problem. I have a 5.0HO engine that when I reset the TDC, removed bad dizzy, I get the timing mark "jumping" around when timing light is used, 15 BTDC is what I need. When I disconnect the spout I can set it OK and runs great but when I connect back for computer control, has a A9L with fresh tune SCT chip, it will not start, remember the jumping mark. Did I index the dizzy wrong? Retarded or advanced it 1 tooth off? Need some help here, thanks.
ps The engine is custom Jasper Racing with a Vortech 50lbs. injectors, all custom parts inside going thru a Zoom clutch to a T-56 race trans, to a 8.8 rear Posi all inside a Volvo 744. youtube has it "V-8 Volvo spanking a Porsche"
pps thanks for your help! timetrialman59

 

[liljoe07]

Thats normal. And its not really the TDC mark jumping, its the timing of the spark as its detected by the timing light.

With the SPOUT in the ECM uses spark as an Idle control function. So it will jump around. Dont sweat it.

That being said, you set the timing with the SPOUT plug out, and let the ECM do its thing when the SPOUT is installed.

 

[Tanus]

post pics if you got them, I gotta see this thng

like said above, set to 12-15 with spout out, timming light show be super steady with it disconnected.

 

[timetrialman59]

Thanks it's fixed! Will post pics. soon!