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.

Diverter valve

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by RedBrute, Feb 16, 2003.

  1. RedBrute

    RedBrute 1/2 ton status

    Joined:
    Sep 22, 2002
    Posts:
    346
    Likes Received:
    1
    Location:
    Southern tier New York
    Is there any way to check the diverter on my '87 for proper operation? My understanding is this sends air from the air pump either to the exhaust manifolds or to the air cleaner as conditions require. I hooked a vac pump up to it and can pull vac on it but it bleeds off quickly. Is this a valid test or am I chasing my tail. The reason for this is I plan on legal headers this spring and want all the emmisions stuff working as required by law. I've checked from the manifolds back to the "D" valve and realized this thing may be smarter than I am right now. /forums/images/graemlins/blush.gif Any experts or "PROFESSORS" /forums/images/graemlins/smirk.gif out there. /forums/images/graemlins/confused.gif
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    I don't know all the controls for the divert valve, so you probably need to look it up in a manual for your year...

    Likely run by engine temp, so at startup, the divert valve should be sending air into the exhaust manifolds, at operating temp, into the air cleaner. You could *probably* disconnect the hose and pay attention to where the air is going when its cold, and once its warm.
     
  3. RedBrute

    RedBrute 1/2 ton status

    Joined:
    Sep 22, 2002
    Posts:
    346
    Likes Received:
    1
    Location:
    Southern tier New York
    I never thought to check it cold, only checked when it is fully warmed up... thanks for the response. /forums/images/graemlins/thumb.gif It's 3 degrees out right now, think thats cold enough /forums/images/graemlins/eek.gif I think I'll take this back up in the spring time /forums/images/graemlins/cool.gif
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    I'm with you, now is no time to be tinkiering with the truck outside! /forums/images/graemlins/smile.gif
     
  5. the professor

    the professor 1/2 ton status

    Joined:
    Feb 6, 2003
    Posts:
    130
    Likes Received:
    0
    If its a TBI its simple..

    You get "upstream air" at the exhaust manifolds in "open loop", when the engine is cold..

    Cause the O2 and Cats to heat more quickly, and adds air to lower emissions during warm up

    When it is warm, you get air to the air cleaner...NO air to the exhaust...it will confuse your computer, it will think the engine is lean, because of the extra air

    If its computer carb, it can be more complicated.Usual a big air line to the air cleaner is a giveaway...

    That is the system that works like I said... /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  6. RedBrute

    RedBrute 1/2 ton status

    Joined:
    Sep 22, 2002
    Posts:
    346
    Likes Received:
    1
    Location:
    Southern tier New York
    Thanks to you also "professor". I do have TBI, guess I left that out in my post. Now I have a better understanding of what to look for. My local weather forcaster says a heat wave is coming thursday... may reach 32 degrees /forums/images/graemlins/grin.gif I'll be able to check it out. /forums/images/graemlins/thumb.gif
     

Share This Page