How to correctly set the timing on a 1994 chevy van 5.7

why not ask UNICHIP.
it is their piggyback. ask them. it a custom hack for a car.
how it fits your unstated car and engine, is not knowable.

With a warm engine and timing light ready (engine running) disconnect the single connector (black and brown wire) located on the passenger side firewall. It sticks out of the main wiring harness. Set the timing by rotating the distributor. Clockwise to ****** the timing and counter clockwise to advance the timing. Lock the distributor in place @ 4 deg. before top dead center. Shut the truck off and reconnect the black and brown wire.

Hi:) There is a brown wire with a singal black connector in the wiring harness under the brake booster that goes up behind the engine on the drivers side to the distributor area.You disconnect this wire to disengage the computer timing auto adjustment. Set the timing to 0.deg and turn off engine before reconnecting brown wire. Computer will automaticly set the timing.

The timing (base), is 0 degrees before tdc. Keep in mind the timing connector must be unplugged. usually a brown wire with a black tracer, has a single connector, located under glove box, or by distributor. Thanks...

Is this carbureted or Fuel injected? What size engine? The plug sounds like it goes to the secondary air injection solenoid. If the coil isn't on top of the cap the timing adjust wire is tan with a black tracer and it is taped to the harness near the distributor.

Look on the passenger side floorboard by the firewall. Should be a single connector. Tan wire with a black tracer. Set the timing to 0

THE FIRING ORDER IS AS FOLLOWS : 1-6-5-4-3-2.
CYLINDER NUMBERS (front-to-rear) :
LEFT (driver side) 1-3-5
RIGHT (passenger side) 2-4-6

To set ignition timing, ensure that engine is at operating temperature, (190 degrees or above), bypass EST (electronic spark timing) by unplugging the single tan wire with a black stripe from the distributor. Ignition timing should be set at 0 degrees or TDC (top dead center). If not, loosen distributor hold down bolt and adjust, then retighten.

If the distributor hasn't been taken out, the timing can be set manually but you have to disconnect the distributor wire behind the glove box inside the cab. Tan wire with white tracer it is taped up to the a multi wire harness but is the only one with a single plug. Disconect the plug and use your timing light on the timing mark to set timing per specs. Rotate the distributor as needed to advance or retartd as required for the correct setting. tighten the dizzy clamp and plug the tan wire back together. The computer will now be fooled asd to what the base timing is and advance from there.
Contrary to popular belief, 96' and up do not have this wire. Timing has to be done with a programmable scanner.
Dan
Hope this helps.

0 degrees BTDC would be the spec , there is a brown w/tan tracer wire near the distributor , you have to disconnect the connector before setting timing

look behind the glove box there will be a brown wire with a black strip it will have a disconnect that looks like a fuse holder.disconnect and set the timing then plug it back after timing is set.