bypassing ign module

[customefi]

i was wondering if anyone has bypassed the ign module on a 5l and directly fired an ignition box like a 6al or equivelent. i dont need the bypass control. Does the ign module reshape the crank signal or can the ecu handle it as a direct input.

[Holden202T]

have a search on the net for msd manuals, i remember finding info as to how to wire it to all different setups.

if the computer controls it you will get timing advance, but if the computer isn't involved it wont advance unless you get a dizzy with advance in it, like a pre EFI electronic one or something.

[customefi]

i was actually wondering if the icm does any wave shaping to the ckp signal before sending it to the ecu or can i just run the ckp ref signal straight into the ecu

[VL400]

On a V8 its a 12v signal out of the dizzy, the ref signal going to the ECU is 5v. Why do you want to not run a module? The MSDs can work fine with the factory module.

[Holden202T]

and the ability to have full control of the spark curve!

[customefi]

i was just trying to minimise the components invoveld to sve room on a conversion
when i used my scope both signals were 12v and were both identical to each other

[TTVN]

i think the ecu sends a + signal to the module where the module converts it to a - to fire the coil

usually the msd etc use the - to trigger

not sure if u can configure the msd to fire with a + signal , would possibly depend on the model you buy

also not sure how u would go starting as the module supplies bypass spark until the engine gets to preset rpm to initiate run spark

food for thought?