I need to set the timing on my 87 5.7 IROC. I keep reading in the searches that I need to disconnect the "brown" wire. Well, I don't have a brown wire since this has been rewired. The distributor has two plugs in it. I have tried unplugging them one at a time, but with either one unplugged, the engine won't start. I'm kinda stuck. I'm sure it's something obvious, but my amateur brain isn't seeing it. Near as i can tell the timing is in the 2-4 degree range. The engine bogs down on acceleration so I'm guessing this is the problem. Fuel pressure is fine. Anyway, any suggestions would be greatly appreciated.

Steve

 

Would you set the timing different with the msd than one would normally run or would it be the same? Did you get any instructions.

 

As far as I know, it's the same. I didn't install it. Done by PO. MSD was no help. All they told me was to disconnect the brown/tan wire.

 

Well I know someone will jump on here that knows more than we do but can't you just unhook the multi spark box and set timing as you normally would.

 

Is the multi spark box the small black box under the dash? I did find a tan w/black stripe wire under the dash. There isn't any way to unplug it individually but it goes into a plug with a bunch of other wires into a small black box on the passenger side underneath the dash.

 

I do not know for sure but if that is the tan wire associated with the msd make sure you don't do anything you can't fix! I thought the muti spark box was the red box usually mounted on the firewall.

 

Ok you're refering to the 6AL box. It doesn't control the advance as far as I know. The ecm still does this. The 6AL just boosts the power to the spark.

 

The "brown" wire is not near the distributor. It should be by the firewall towards the passenger side. But it sounds like someone put in a non computer controlled distributor which would be why you don't have very good throttle response since the computer is not advancing the timing. It would help if you gave the model number off the distributor and ignition box.

 

All right so what do you do next? Look for that wire some more I guess.

 

MSD model 8366 with 6AL and MSD coil. Like I said, I found a tan with black stripe wire under the dash but no way to unplug it. What exactly am I looking for under the hood? A tan with black stripe wire with a plug? Obviously there has to be a somewhat convenient way to uplug this wire since this is a function that has to be performed whether the engine is modified or not.

 

You're good on the distributor as it is computer controlled.

Take a look here for detailed instructions to set your timing.
https://www.thirdgen.org/settingtiming

 

I knew we would get you some help what a thread that is let me know if it works.

 

Here's a photo of the tan wire with the black stripe to be unhooked. Its near the fan motor on the passenger side.