87 tbi 305 est issues

[rusty but trusty]

Hello i have a issue with my electronic spark timing system. with the bypass wire unhooked i have the timing set to 0. but when i hook the wire up it runs very bad mostly backfiring and running rough the wire between the ecm and connector shows some resistance between it alone and unhooked from everything but not a lot what would be a good place to look? for the short

[roboticjunky]

Did you check your knock sensor and the wire going to it?

[rusty but trusty]

The wiring and the knock sensor are both good but the est wire from the ecm to connector under hood seems to be partially grounded

[zieg85]

I wonder how your timing chain is?

[VileZambonie]

the wire between the ecm and connector shows some resistance between it alone and unhooked from everything but not a lot what would be a good place to look? for the short

Can you be specific about what you are measuring resistance on and why? Verify everything primary and secondary ignition is good and fuel pressure is good. If so check the ECM, prom, ground and EST module.

[rusty but trusty]

the resistance i measured was on the wire that goes through the firewall to the ecm and i completely un hooked it on both ends and it has only a little resistance from it to ground like it was grounded before it goes where it goes