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Since I had to remove the plenum to change the injectors I decided to investigate a little bit under the hood and to check egr valve (negative bp) and the vaccum lines. The lattesr had been modified by the previous owner in order to add a vacuum gage in the dashboard.
I've read the Haynes and the Chilton but I still don't get it. Especially for the vacuum lines if someone can help me out understand the purpose of each hose it would be great.
Here's a link of a video I made which will explain better that any writting.
From port vacuum on plenum, line goes to a tee and check valve. One side goes to the Vacuum ball and tees to the drivers fender for the cruise control. The other side goes to EGR solenoid port. Then from the other solenoid port to the EGR itself. The EGR Solenoid has a vent port on it covered with a piece of foam.
Hi Bob thank you very much for your reply. Now I understand the left side of the vacuum line (Cruise Control et vacuum ball)
What is a check valve?
Could you explain me the vac line which goes out at the rear of the plenum (1'40 in my video) please?
On all the official diagrams it says it goes to "HVAC".
I know it means "Heating, ventilating and air conditioning" but I still don't figure out how does this work and what are the roles of the different lines.
Here is the Vacuum Check valve.
It says in the diagram about going to HVAC. It is one of the hard plastic tubes that comes out of the wire harness on the firewall and goes into the cabin to the HVAC unit controls on the dash
At 3:14 in your video, That is your Heater control Valve. It connects to Valve and also goes straight to the Heater controls on the dash. It opens/closes to send water through the Heated core
I just saw your last post. Really, thank you so much. It helps me a lot. It's been two days that I was seeking through all the web, youtube video... to try and look for a clue.
Hello,
New member here trying to get his son's newly purchased 1989 IROCZ 5.7L to pass smog. No Check engine light. Failed for high NOX so checking the operation of the EGR valve (new). This thread was helpful but cannot view the utube video, so need to ask some questions.
Pic1 is a snapshot of my vacuum line diagram. It's difficult to see the vacuum lines going in/out of the EGR solenoid but my current setup has the top line going to the EGR and the bottom line coming from the throttle body nipple hanging straight down on the drivers side.
Pic2 is a vacuum line coming from the rear manifold nipple into a T. One end is plugged off (how I found it) and the other goes into the firewall which I assume is the HVAC control.
Pic 3 is the vacuum line/rubber connection to the EGR solenoid.
I pulled this plug to test if vacuum was coming from the throttle body nipple when the engine was rev'd. My understanding is the EGR solenoid has a vacuum source on one side and receives a signal from the ECU to allow vacuum to the EGR to open the exhaust gas re-circulation tube back into the intake above a certain speed. The vacuum source in my setup is the vacuum line from the throttle body but I do not pull any significant vacuum when the engine is reving beyond idle.
Pic2 has a plugged off tube. This would be a constant vacuum source suitable for the EGR solenoid. It could also go to a vacuum ball? I'm not sure I have that on the Camaro. It does not have cruise control.
My questions are the following:
1. On the EGR solenoid, please confirm if the vacuum source plugs into the lower or upper nipple?
2. Does the vacuum source for the EGR solenoid come from the plugged off tube in Pic2 or does it go to a vacuum ball? If it does go to the EGR soleniod, how does the vacuum tube from the throttle body nipple tie in? This does not pull a vacuum but I'm wondering if it pulls air from the throttle body inlet after the EGR solenoid releases the EGR of vacuum? It has to be a closed system after the MAF.
I was going to hook up a vacuum gauge to the hose going to the EGR, route it into the driving compartment, and drive the car to see if a vacuum is present above certain speeds, confirming the EGR solenoid is working. I need to know where the vacuum source is coming from into the EGR solenoid.
Any pictures of this area would be greatly appreciated.
I'm a new member trying to pass smog for my son's 89 IrocZ. It failed for high NOX so I wanted to test the EGR function. EGR is new, EGR solenoid is not. This post almost provided the detail but I cannot see the utube video.
Pic 1, Is the Vacuum line diagram for the EGR and EGR solenoid.
Pic 2, Is a capped off line from the intake manifold which I found. The T fitting goes to the HVAC line inside the car. The capped off line may go to a vacuum ball or EGR solenoid, not sure which.
Pic 3, Is the plug into the EGR solenoid which I pulled to verify vacuum source and attempt to see if the solenoid was working.
My plan was to hook a vacuum gauge T'd into the line going to the EGR. into the car and drive it, confirming at speed the EGR gets vacuum to open and close the exhaust port.
I need help on the following issues:
1. I do not get a vacuum source from Pic 3 plug. One line goes to the EGR. The other line goes to the throttle body nipple handing down on the drivers side. Can someone confirm where the vacuum source comes from to the EGR solenoid? I suspect Pics capped of line is it.
2. If the vacuum source to the EGR solenoid is Pic 2 capped off line, how does the line from the throttle body tie into the EGR solenoid or line to EGR?
Anytime
