How to set timing on TBI?
How to set timing on TBI?
I have a chiltons manual that says for 4bbl cars disconnect est connector,for TBI ground ALDL connector,for TPI dissconnect tan wire w/black stripe.I have a 92 305 TBI so i grounded ALDL to set base timing.When i took intial reading it was ooff the timing tab at what i would guess to be 14-16* BTDC so i turned it back to 8* but doesnt seem to be quite right now . slight hesitation, idles consistent but kinda rough.Just did this earlier so I hanent had a chance to look for tan w/blk wire like everyone here says to do regardless of FI system.Is chiltons wrong and i need to find this wire and dissconnect to do this right instead of grounding ALDL?
Joined: Dec 2005
Posts: 6,499
Likes: 31
From: Macon, GA
Car: 1992 Camaro RS
Engine: Vortec headed 355, xe262
Transmission: T56
Axle/Gears: 9-bolt 3.70
Re: How to set timing on TBI?
I dont know what you mean by the aldl connector? I never bothered with anything like that.
There is a plug over near the passenger side strut mount that you unplug after you got the car warmed up and running, then set base timing to zero. Turn the car off, disconnect the battery and let everything reset itself. Turn it back on and you should be good to go.
That plug is... and I may be wrong on this.. but I think it's the ESC connector. Either way, the computer uses it to adjust timing. So if you leave it connected, the computer will keep moving the timing to counteract your adjustments so you never get anywhere until it's so far out the computer will stop adjusting it back. So what's going to happen is the car will run fairly badly since the computer is being told that the base timing is at a certain place, and the distributor is set at a different place.

See the loom that goes around the back of the AC condenser? There should be a plug/connector around there somewhere. You can actually see the one on mine in the picture but it's hard to notice because of the angle.
There is a plug over near the passenger side strut mount that you unplug after you got the car warmed up and running, then set base timing to zero. Turn the car off, disconnect the battery and let everything reset itself. Turn it back on and you should be good to go.
That plug is... and I may be wrong on this.. but I think it's the ESC connector. Either way, the computer uses it to adjust timing. So if you leave it connected, the computer will keep moving the timing to counteract your adjustments so you never get anywhere until it's so far out the computer will stop adjusting it back. So what's going to happen is the car will run fairly badly since the computer is being told that the base timing is at a certain place, and the distributor is set at a different place.

See the loom that goes around the back of the AC condenser? There should be a plug/connector around there somewhere. You can actually see the one on mine in the picture but it's hard to notice because of the angle.
Last edited by InfernalVortex; Nov 18, 2007 at 11:03 PM.
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: How to set timing on TBI?
Your manual is wrong. For a TBI you disconnect the tan/black wire, same as a TPI car.
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