Northstar Engines and System Technical Discussion Discussion, EGR Valve and Throttle Body in Cadillac Engine Discussion; Where are these located? How can I get to them and clean them. I have a 1998 STS. I am ...
Where are these located? How can I get to them and clean them. I have a 1998 STS. I am car illiterate but want to learn. Please help me!
You have a Northstar engine so it would be better to post in the Northstar section...not the 4.9 section. Those two are completely different engines.
Go to www.helmsinc.com and order the factory service manual for your car. Helms publishes the manual or order one from the dealer...or watch ebay as the service manuals are often available on there. It will show you where everything is an explain the operation of all the items on the engine and in the car. If you really want to learn about your car so that you can work on it yourself or just be knowlegable on how it works then the factory (not chiltons or haynes...) manual is the way to go. It is the cheapest thing you can buy that will help you the most over the long run. It has complete system operating instructions and descriptions as well as diagnostic troubleshooting diagrams for the whole car...and step by step repair procedures.
Follow the inlet duct from the air cleaner to the engine. The throttle body is the silver part with the throttle shaft sticking out of it that the large rubber inlet duct is attached to.
Look immediately beneath and beside the brake master cylinder booster...the EGR valve is a round cylindrical device about the size of an orange juice can standing on end with a wiring connector sticking out of the top.