Where's the ECM plug that you diconnect to time? On mine it's suppost to be tan and black in color.
Also I havn't used my timing light in a "few years" and it's not working. I don't think that I've used it a dozen times. It's a Craftsman.
Is there anything that I can do to get it working again or to check?
The timing light has a advance on it. Isn't this so that you don't have to disconnect the ECM?
Thanks! :thumbs:

 

ON mine, it is a single connector that is black and it isREAL close to the Brake Booster. Sorry...I am not sure about your questions on the timing light...I just went and bought a new one for $29.99 and it works fine.

 

You still need to disconnect the EST bypass wire, regardless of your timing light. It should be a single wire connector that comes out of the big engine harness near the brake booster. On mine it's near the bracket that holds the wiring harness to the firewall, just above the #7 exhaust.

Jason

 

Thanks man. I'm going to go take a look see again. The sticker on the radiator made it sound like the wire went to the distribitor.

 

Err. it does...it is just that the connector is by the power booster because it's a little more convenient to get to. Hell, F@rd puts their SPOUT (spark output) connectors on the inner fenderwells, kinda like where they occasionally put their EST modules.

You disconnect the wire and then timing is all controlled by the EST module. At this point, advance is fixed via the module. There is some built in advance with the module, but you're not gonna want to write home about it. At ~400RPM, your ignition setup usually switches from this advance to ECM advance. If you have the bypass wire disconnected, you won't have the ECM controlling the advance. It's GMs way of KISS.

If your timing light has a dial on it, it's probably a 'dial-back' timing light. Kinda handy when you can't find the right balancer tab to install on your timing cover if you are using a bastardized cover and balancer setup. Basic idea is to dial the light til the 0 mark on the balancer crosses the zero mark on the timing tab. Then you look at the dial and you read your advance off the dial. But you still disconnect the bypass wire to set base timing, because the idea is to set base timing. If you keep the wire connected, the ECM advance is going to be different at different temps, etc. After you set it correctly, you could 'map' out the timing with the dial-back light. Compare different advances with vacuum readings, IAC operation, gets kinda deep, but that's stuff to mess with if you have a lot of free time and want an idle that appears to be stock with a cam that is far from it.