Do the envoys have an EGR valve that the trailblazers dont have? I noticed my 05 Envoy had one on the head, passenger side. The engine I just put it in came out of an 05 trailblazer and it just had a block off plate where the EGR was on my other engine. I thought someone just removed it until I looked at my friends 02 Trailblazer and saw the same block off plate, and my parents 2004 Trailblazer also just has the plate. Whats the deal with this?
No EGR on some 4.2L?
- Thread starter Catriderf7
- Start date
Mounce
Member
It's called SAIS (secondary air injection system) I'm not sure if that's the same as EGR or not. But, some motors had it and some didn't. All of the 4.2's for the GMT360's work the same and are interchangeable so it's nothing to worry about. I'm not sure but it might throw a code for it.
Thats what I figured I saw the hoses went to an air pump under the driver seat area. Im just wondering why its on some and not others. Im sure ill get a check engine light because I have a connector not plugged into what I thought was the EGR valve. Apparently its not called an EGR valve cause autozone doesnt have any parts listed for EGR valve, Although they they have a gasket, and block off plate? Ill wait and see if anything comes up on the dash
smt 59
Member
You will throw a code, its a dealer part about $50, two bolts, put it on and save the aggregation.
Mounce
Member
I think it started in 2004 but it was kinda scattered as to which got it. Like the EXT's from the Oklahoma plant (what I have) didn't get them.