1990 305 tbi timing procedures

[White_Beast98]

I replaced my starter because it was locking up. I am not a profesional just really good with my hands. I don't know all the secrets of automotives yet but I am trying to gain experence hands on. I need some wisdom to be pasted to me on how to time my distributor and get my RS starting at the tip of the turn. Can anyone sprinkle me with their knowledge so I can gain a touch more experience in my quest.

[wrightz28]

1-Disconnect the ECM ref wire, (tan, single wire), the quick disconnect is on the fire wall, right (passenger) side.

2-locate the timing index tab on the motor, below the water pump, just above the balancer. It will probably need a cleaning in order to determine the marks for +/- TDC. Usually seen from the left (driver's) side of car.

3-hook up your timing light according to the manufacturer and type of light being used.

4-loosen the distributer hold down bolt.

5-fire it up, point the light at the index tab and pull the trigger, you should then see the timing mark on the balancer pointing to where the ignition timing is in relation to cylinder 1 TDC. Stock is zero degrees. I like to throw a few degrees advance at it, around 4 for a little extra pep. You simply turn the disributer fore(retard) or aft(adv) to achieve.

6-when it's all said and done, tighten down the hold down bolt (no need to get really nuts on it) and recheck to make sure it didn't turn the dist. while tightening.

7-reconnect the tan wire.

***note 1, if the timing mark on the balancer is inconsistant on staying in the same spot on the index tab (jumping) it's a pretty good indicator that the timing chain is due.

***note 2, check your emessions label on the radiator fan shroud or hood for any vehicle specific steps not covered.

[Nate355RS]

That sounds about right. If you have any trouble finding anything like the EST connector that you have to unplug that comes out of the wiring harness on the passenger side, just let us know. Also if you don't want to clean up the index tab you can just follow this pic.

Pic is from thirdgen.org but it originally came from MonteCarloSS.com

[zman204]

i have a 90 camaro rs with the 305, i have set the time with the ecm wire connected, and disconnected, the timing mark does not dance around like it has a bad timing chain, but still seems to have a bit of a rough idle, like in the case of a bad plug wire, but they have all been checked and are good. then under any load, it will pop through the throttle body, any ideas?

[wrightz28]

Improper plug gap?

Weak spark?

Fuel pressure problem?