EGR system question

[That One Guy]

Hello all. I've been searching for a diagram for the EGR system for my truck that I just picked up but haven't been able to find one specific to mine. The truck is an 03 b2300 that I picked up recently for $600 so I expected it would need some work, but oh boy did this guys "mechanic" do some interesting things to the truck. The EGR vacuum solenoid control valve is completely bypassed so I'm curious if any of you can give me an idea of where it is supposed to be in the system. Pics below of what I'm referring to.

I took this as a reference picture when looking for the part so please let me know if it is not enough to go off of. It's bolted to the bottom right of the intake manifold when looking through the driver side wheel well. The hose isn't connected to anything so it's essentially disconnected from anything but the electrical connector.


Looking from the top you can see the two elbows connecting the vacuum lines(I may be identifying these incorrectly) running from the vapor canister purge valve to the other side of the engine. I feel like these shouldn't be connected this way but car engineers do some crazy things when laying out engines sometimes.


I'm typing this out on mobile so I apologize if the formatting is horrible. Thank you for any help in advance.

 

[adsm08]

I am not overly familiar with that engine, but IIRC the EGR system uses an electric valve bolted to the back of the head, not a vacuum actuated one. This one sticks out to me because of all the shit you go through to get to it.

That valve you pictured looks like an evap purge valve, which is consistent with your statement that it is hooked to the canister. EGR would be hooked into the exhaust, not the evap system.

After the purge valve the evap line can be hooked to any appropriate port on the intake.

 

[That One Guy]

Yeah, they tucked it pretty far down in there. I only noticed it when I was doing the PCV valve.

If I'm understanding you correctly, the line coming from the canister should be running to the purge and then exiting to the intake so the 2 elbows connected together are supposed to be going down to it.

If so, are the inlet/outlet sides marked specifically on these usually?

I appreciate the help.

 

[Soledad]

That solenoid valve you show above is actually the IMRC (Intake Manifold Runner Control or Intake Manifold Swirl Control) solenoid valve. And the missing hose connects to the intake manifold.

So, using that picture, the missing hose connection runs to side of the intake manifold where a similarly small vacuum nipple is located. Then the vacuum hose pointing down on that solenoid runs to the back of the intake manifold and connects to the IMRC vacuum actuator. It is located on the back of the intake manifold and almost up against the firewall and is a real pain to get at and see. You'll need to use a good flashlight and an inspection mirror to see it. The IMRC actuator uses a vacuum signal from the IMRC solenoid to move an arm that opens and closes the intake manifold runner flaps during a certain RPM.

 

[That One Guy]

Awesome, thank you Soledad that's just what I was looking for. I'll run with that info and attempt to locate them and report back.

Apologies to the admins for posting this in the wrong forum originally. I read the (no tech articles) after the fact so thank you for moving the thread to the appropriate forum.

 

[That One Guy]

Got everything routed correctly again. For some reason they had bypassed the valve in question and just run a line from the intake up to the actuator on the back.

It's still studders a bit while idling and at certain RPM driving but I'm going to give that a tank of gas or two and see if it smooth's out since the truck sat for a few months. No codes so it doesn't lead me to believe there is a more serious issue lurking but time will tell.

Thanks for the help.

 

[transplant]

There are a couple write ups within the last few years about problems with the IIRC system when I was looking for some answers.

 

[That One Guy]

The stuttering issue seems to have been gas as I was hoping. It has pretty much stopped doing it after putting some mileage on the truck and idles and drives now very smoothly.

Since putting the IMRC solenoid valve back in the loop none of the codes have come back and it was able to pass inspection so I'm happy about that. It still needs quite a bit of work to increase quality of life but it functions as a work horse like I need it to for now.