How to check and set timing??

[lennyg]

Just bought a 95 tahoe 4x4 5.7tbi for my sons 16th bday.
The engine was running really rough when i got it. I went to check to make sure the previous owner didn't have any of the spark plug wires crossed and when i grabbed the distributor to check to make sure the plug wires were seated, the dist was able to turn very freely. Prob now is I don't know how to put it where it needs to be.
I have a timing light but I thought the timing was all controlled by the computer.

Any suggestions???

Thanks:

 

[samotahoe]

2. Put the IC system in the bypass mode by disconnecting the "set timing" connector. This is a single wire sealed connector that has a tan with black stripe lead. This connector breaks out of the wiring harness below the heater case in the passenger compartment. 3. With the ignition switch "OFF," connect the pickup lead of the timing light to the number one spark plug. Use a jumper lead between the wire and plug or an inductive type pickup. DO NOT pierce the wire or attempt to insert a wire between the boot and the wire. Connect the timing light power leads according to manufacturer's instructions. 4. Start the engine, and aim the timing light at the timing mark. The line on the balancer or pulley will line up at the timing mark. The timing should be O° TDC. If a change is necessary, loosen the distributor hold-down clamp bolt at the base of the distributor. While observing the mark with the timing light, slightly rotate the distributor until the line indicates the correct timing. Tighten the hold-down bolt, and recheck the timing. 5. Turn "OFF" the engine and remove the timing light. Reconnect the number one spark plug wire, if removed. 6. Reconnect the "Set Timing" connector.

first you need to find the "set timing connector" and connect it accordingly. then you can adjust the timing. if it has a distributor then it can be adjusted. the individual coil packs are controlled by the PCM.

and the connector for the timing can be found passenger side under the glove box by the heater control module
good luck

 

[lennyg]

Thanks for the reply and help.
Starts right up now, even with one of the injectors not firing.