TBI Swap - Finding EST Wire
 

Just picked up an '83 with an '87 TBI engine swap. I would like to set the base timing and need to unplug the EST wire. I can't seem to find a tan/black wire anywhere. Where does the wire connect? I am thinking it might be easier to track it down if I know where it connects to. Does it go to the distributor? Is it normally a lone single wire or is it normally bundled with other wires.

Sorry about the basic question, but I am new to TBI engines

Thanks
Doug

Re: TBI Swap - Finding EST Wire
 

Look for a 4wire distributor plug that plugs into ICM (ignition control module) - it should be tan color wire at Pin B along with other 3 wires. From there you can trace it to the set EST connector. Dizzy plug should have the following wires:

Pin A Black-red
Pin B Tan-white
Pin C Purple-white
Pin D White

Sometimes set EST connector is hidden inside harness or taped.

//RF

Re: TBI Swap - Finding EST Wire
 

Thanks for the reply.

I looked behind the distributor and found 2 plugs. One has 2 wires and one has 4. It's tough to see but it appeared the four wired plug had a tan wire. Since I could not see to follow the wires I used my hand to follow the path. The wires ran down and into some plastic wire covering, which tee'd into a larger loom with plastic wiring covering. I followed the larger wire loom, hoping to see a single tan wire with a junction coming out at some point.

Under the hydroboost unit, I found this (pictured and circled in red). Does this look like the correct wire and connector? I expect when I disconnect this I should see the idle drop and timing to retard - correct?

Thanks again
Doug

Re: TBI Swap - Finding EST Wire
 

That is it, and yes.

Re: TBI Swap - Finding EST Wire
 

Yes, that's the set EST connector. Make sure that engine is warm and idling steadily. Once you set timing, secure dizzy, shut engine off and disconnect battery for 30 seconds to clear code 42 (this is normal). Stock LO5 engines is spec at 0 deg, but +2 deg will give you a touch more power.

//RF

Re: TBI Swap - Finding EST Wire
 

Thanks all

Once it gets out of the single digit temps, I will go out and check the timing along with a long list of other items I need to address

Doug