L81 base timing, help please!
Thread Starter
Intermediate
Joined: Oct 2005
Posts: 42
Likes: 0
From: Saratoga Springs UT
L81 base timing, help please!
Hi, I’m trying to setup the base timing on my L81 (HEI with ECM). What cable(s) do I need to unplug to disconnect the ECM advance? Is it the 4 plugs connector coming from the back of the distributor? I also heard about a single connector (tan and black wire) to unplug but can’t find it anywhere. I only have the 4 plug connector. I tried to setup the timing with the 4 plug connector unplugged but it doesn't seem right...
The original owner also added a Mallory Hyfire 29029 electronic ignition control. Can I still setup the base timing with it or do I need to unplug it?
Thanks,
The original owner also added a Mallory Hyfire 29029 electronic ignition control. Can I still setup the base timing with it or do I need to unplug it?
Thanks,
Race Director
Joined: Jul 2004
Posts: 12,703
Likes: 329
From: Scottsdale Arizona
Assuming that the computer still controls the timing advance with the Mallory module, then yes, all you need to disconect is the 4 post connector leading to the firewall wire harness. Set your base timing (at the correct RPM) and reconnect.
No idea what effect, if any, the Malory module has. if it is simply a high performance module designed for this application, then it shouldn't matter. If it is designed for a non-ECM application, then you probably aren't getting any advance. Easy enough to check. Disconnect the 4 prong wire. Set your timing. Reconnect the harness. Recheck timing. If the timing mark hasn't moved, you've got no advance.
No idea what effect, if any, the Malory module has. if it is simply a high performance module designed for this application, then it shouldn't matter. If it is designed for a non-ECM application, then you probably aren't getting any advance. Easy enough to check. Disconnect the 4 prong wire. Set your timing. Reconnect the harness. Recheck timing. If the timing mark hasn't moved, you've got no advance.
God bless, Sensei
Thread Starter
Intermediate
Joined: Oct 2005
Posts: 42
Likes: 0
From: Saratoga Springs UT
I unplugged the Mallory Hyfire and was able to set the base timing. Looks like it's either shot or not compatible with the ECM because I don’t get any advance when it’s hooked up!
Thanks guys!
Love this forum plenty of info for our sharks and very good people!
Thanks guys!
Love this forum plenty of info for our sharks and very good people!
