Results 1 to 6 of 6

Thread: new exhaust => low idle

  1. #1
    Van Enthusiast
    My Van(s):
    '88 4x4 5 speed manual
    Join Date
    Dec 2018
    Location
    ME
    Posts
    146
    Rep Power
    1

    new exhaust => low idle

    Got a new catalytic and muffler. The cat is a Walker from Rock auto, but my exhaust shop had to fabricate some pipe and said he ended up using a muffler from a Honda Civic.

    The muffler pipe is definitely small and I can see the connection from the cat to the muffler is downsized (pic)

    When I picked it up I notice it idles much lower - HOWEVER he also has not hooked back up the downstream O2 sensor yet since he got the wring sized flange and had to order..

    So I am wondering - is the low idle from the missing O2 (we will put it in next week) OR is it perhaps from the downsized muffler pipe?

    Thanks.

    '88 4x4 5 sp
    Attached Images Attached Images   

  2. #2
    Van Fan
    My Van(s):
    95 Previa SC, RWD, Auto
    Join Date
    Feb 2019
    Location
    Columbus, IN
    Posts
    27
    Rep Power
    1

    Re: new exhaust => low idle

    At what RPM is it idling?

    Did the battery get disconnected? Any other work done up front? vacuum leaks?

    So you have TWO O2 sensors in 88? cali emissions I take it? downstream should have no effect on the idle, it's only there to verify the cat is working.

    It's unlikely the smaller muffler is causing a lower idle, while it may be more restrictive, idle is when it matters the least.
    -Russell
    "You don't get to judge me for how I fix what you break"
    -95 Previa SC RWD
    -05 Subaru Baja Turbo, 03 Subaru Baja NA, 01 BMW R1200c, 94 Firebird v8, 70 VW Beetle

  3. #3
    Van Enthusiast
    My Van(s):
    '88 4x4 5 speed manual
    Join Date
    Dec 2018
    Location
    ME
    Posts
    146
    Rep Power
    1

    Re: new exhaust => low idle

    sub 1K on the idle.

    I think you answered it for me. No affect due to smaller pipe and the downstream cat will not affect idle, so I will get the exhaust work completed and look into other options after that.

    It was decent idle (1100-1200) before the work done except for when I turn the heater on it would dip to 1K, so exhaust work could just be a coincidence I guess.

  4. #4
    Van Obsessed
    My Van(s):
    1988 4WD LE auto dual range t-case (the mistress) 1988 4WD LE auto(the donut van)
    Join Date
    Aug 2012
    Location
    Tacoma, Wa
    Posts
    565
    Rep Power
    1

    Re: new exhaust => low idle

    11-1200 rpm at idle is too high. Idle speed should be 750 for A/T and 700 for M/T.

  5. #5
    Van Enthusiast
    My Van(s):
    '88 4x4 5 speed manual
    Join Date
    Dec 2018
    Location
    ME
    Posts
    146
    Rep Power
    1

    Re: new exhaust => low idle

    ah, got it. Pretty sure she would stall at that low an idle currently - guessing I'll brush up on the "low idle" and "leaky vacuum hoses" thread ;)

  6. #6
    Van Fan
    My Van(s):
    95 Previa SC, RWD, Auto
    Join Date
    Feb 2019
    Location
    Columbus, IN
    Posts
    27
    Rep Power
    1

    Re: new exhaust => low idle

    Quote Originally Posted by cpginkpt View Post
    ah, got it. Pretty sure she would stall at that low an idle currently - guessing I'll brush up on the "low idle" and "leaky vacuum hoses" thread ;)
    lol That was going to be my suggestion: fix what causes it to run poorly at proper idle.
    -Russell
    "You don't get to judge me for how I fix what you break"
    -95 Previa SC RWD
    -05 Subaru Baja Turbo, 03 Subaru Baja NA, 01 BMW R1200c, 94 Firebird v8, 70 VW Beetle

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •