1990 Chevy BB timing

[llih]

Just finished installing a new 454 in my 1990 TBI suburban. The truck has OBD1 and is a California vehicle. The problem I am faced with is setting the timing. This is the only Chevy I have owned, that is new enough to have OBD. What needs to be disconnected to set the initial base timing? The truck sticker is showing 4 degrees before TDC. I have the truck running and the cam broke in. I tried setting the timing without disconnecting anything, but it doesn't seem to be correct. I am also getting error codes 33 and 45. They are supposed to be low vacuum or high signal from the map and a rich exhaust.
Thanks Brad

 

[ToyotaDon]

Look for the EST connector (tan with black stripe) near the distributor. The connector is round in shape and about 2" long. When you disconnect it, the SES light will come (if not already on), and the engine RPM will change.
The other codes you may need a book with a trouble tree to follow, and track down the source of the issues.

 

[llih]

Found it and got it all squared away.
Thanks
Brad