Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

name this egr related part, what does it do???

Discussion in 'The Garage' started by GMCLegacy, Nov 22, 2005.

  1. GMCLegacy

    GMCLegacy 1/2 ton status

    Joined:
    Jan 24, 2002
    Posts:
    620
    Likes Received:
    0
    Location:
    Grand Haven, MI
    i'm attempting to get a 92 tbi 350 to run without hesitation. after searching around here i decided to throw a new egr in. this didnt solve a thing. long story short, the truck runs good if i bypass "unknown part".

    it is inline with the vacuum line that feeds the egr valve. it has a 2 prong connector on it. is it needed, if so, what does it do? the truck seems to run good with straight vacuum on the egr.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    It's the EGR solenoid. It opens to allow engine vacuum to pull the EGR valve open.

    It wouldn't be there if it wasn't needed.
     
  3. GMCLegacy

    GMCLegacy 1/2 ton status

    Joined:
    Jan 24, 2002
    Posts:
    620
    Likes Received:
    0
    Location:
    Grand Haven, MI
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    It's open or closed. Receives a signal from the ECM and it opens.

    There are typically three "connections" on the solenoid, one barbed that is a VENT line. The other two from my experience use a formed rubber plug so you can't hook them up wrong, but not sure what the '92 truck piece looks like.

    With it disconnected you are "bypassing" EGR as a whole, so that doesn't mean the solenoid is the cause. Did you clean out the EGR passages when you replaced the valve?
     
  5. GMCLegacy

    GMCLegacy 1/2 ton status

    Joined:
    Jan 24, 2002
    Posts:
    620
    Likes Received:
    0
    Location:
    Grand Haven, MI
    i did not clean the egr passage, mainly because i could not see any build up. i think i replaced a working egr valve. i am thinking it is a solenoid problem because if i run a vacuum line from the tbi to the egr it runs good.

    i put the solenoid back inline and could not get vacuum at the egr. at what point(s) does the ecm tell the solenoid to give the egr vacuum?
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    ECM is programmed for what conditions to operate in, generally it will be with steady cruise. (time at speed threshold probably, with high engine vacuum)

    There are two general types of EGR valves, I'm not quite sure how they work if vacuum isn't used to pull the valve open, or if it's just another way of doing the same thing.

    If you can put vacuum to the EGR at idle and it runs ok, something is either wrong, or the valve operates differently than the ones we commonly deal with on the trucks. You've made sure that whatever line you are hooking up to the EGR is also clear of blockages and doesn't leak?
     

Share This Page