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Discussion Starter #1 (Edited)
Howdy
My envoys been running flawless and I’m very happy with it
But sadly Iv been smelling a little gas and I noticed my fuel pressure regulators got a small leak, since it’s stock and the truck got 208k it’s about time to replace it.
How difficult is it to replace? it seems pretty straight forward but I’m a bit iffy on messing with fuel lines..
The last thing I wanna do is disconnect the battery during this and mess up my hvac actuators, idle and who knows what else.. I’m so not ready for this ):
There aren’t any reliable mechanics near by either so sadly I have to figure this out somehow
 

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2004 chevy trailblazer_lt
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If you have the proper tools - socket set with Torx bits, fuel line disconnect tools, screwdrivers, end wrenches, etc., it is not a terribly difficult job. There are a couple of youtube videos on how to do this job. Just take your time, take pictures as necessary and you should be fine. Disconnecting the battery should not mess up the HVAC actuators.
 

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Disconnecting the battery WILL trigger an hvac actuator recalibration upon powering up afterwards, during which the actuators will operate until they hit their mechanical stops at which time the old brittle plastic gears often do fail. A valid concern for an aging system.
 

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Yes, I realize that disconnecting the battery does trigger the HVAC actuators to recalibrate when the vehicle is next started. However, I don't think the risk of failure is significantly higher than when one changes modes or temperature, but, I could be wrong.
 

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Discussion Starter #5
I disconnected the negative battery terminal and went ahead with replacing the fuel pressure regulator
I had no problems with my hvac controls thankfully and the truck is running like new, no more sputtering and stalling and gas fumes I’m very happy
 

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I disconnected the negative battery terminal and went ahead with replacing the fuel pressure regulator
I had no problems with my hvac controls thankfully and the truck is running like new, no more sputtering and stalling and gas fumes I’m very happy
Can any one help me find the location of the fuel pressure regulator on my 05 gmc envoy slt elite? It seems that the 05 is a little different from the 03-04 models. Cause the 05 doesn't even have an external fuel filter I found out. They are calling the filter the pad at the bottom of the fuel pump, the only filter this year has.
 

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However, I don't think the risk of failure is significantly higher than when one changes modes or temperature, but, I could be wrong.
Well we all can be wrong at times!

As I understand it during normal operation modes are changed by driving the actuator(s) to a particular spot as determined by 'counts'. These counts can be observed with a Tech 2 scanner. However, to know where these spots are the controlling module needs to calibrate by driving the actuator first in one direction until it hits a hard stop where it can turn no more, and then reversing in the other direction again until it hits a hard stop. These actions, hitting the hard stop, are only done during a calibration after power loss or as commanded by a scan tool. When the actuators were new it didn't break anything but now when these plastic gears are at the least 10 years old and getting brittle, they can break under the strain of the hard stop.

This is what I've read on this and several other forums.

  1. Naturally, I could be wrong!
 

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There's several great videos in YouTube on resetting your actuators. I just replaced both of my rear actuators on my 02 TB and they are all plastic. The gear wheels were so badly brittle they fell apart inside the box. The tip to the blend door (inside of the air box) is plastic and one of the 2 on mine was broke, not allowing the door to switch from heat or ac. It's been a pain because you can not just buy the door. I'll attach a picture. I had to order a full air box, my ac and heater core didn't fix into it. So I took the new shaft(doors) out and installed into my box. If you mess with any of the actuators use caution they are old weakened plastic and will snap off. Pull the acuator straight out. One thing I know from having plenty of time waiting on the new air box, I took the broken acuator apart and the shaft door tip was glued to the gear! Thus the shaft was broken before and was glued together. If that is able to be done the epoxy glue is perfect however, it needs time to dry or it will glue to the acuator gear.
 

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There's several great videos in YouTube on resetting your actuators. I just replaced both of my rear actuators on my 02 TB and they are all plastic. The gear wheels were so badly brittle they fell apart inside the box. The tip to the blend door (inside of the air box) is plastic and one of the 2 on mine was broke, not allowing the door to switch from heat or ac. It's been a pain because you can not just buy the door. I'll attach a picture. I had to order a full air box, my ac and heater core didn't fix into it. So I took the new shaft(doors) out and installed into my box. If you mess with any of the actuators use caution they are old weakened plastic and will snap off. Pull the acuator straight out. One thing I know from having plenty of time waiting on the new air box, I took the broken acuator apart and the shaft door tip was glued to the gear! Thus the shaft was broken before and was glued together. If that is able to be done the epoxy glue is perfect however, it needs time to dry or it will glue to the acuator gear.
 

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