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.

Thinking of doing the unthinkable... *Rotor to cap gap. Normal?*

Discussion in 'The Garage' started by y5mgisi, Jan 26, 2007.

  1. y5mgisi

    y5mgisi 1 ton status

    Joined:
    Aug 11, 2002
    Posts:
    17,156
    Likes Received:
    247
    Location:
    Portland Oregon
    I am at my wits end with my surging at idle issue on my 90 and cannot think of anything else to try. I think i have to take it to a mechanic:( . I just feel totaly lost and helpless. ive done everything i can think of and nothing helps. Today i had the injectors rebuilt becasue in my mind i knew that that was the problem for sure! but i put it all back together and guess what? no change... I just dont know what to do. I can rebuild a motor and an automatic transmision but i cant solve a stupid idle issue on the most simple of fuel injection systems. I am just going to feel like so much less of a man handing the keys over to someone else becasue I cant fix the problem...:frown1: :dunno:
     
    Last edited: Dec 3, 2011
  2. jk5blazer

    jk5blazer 1/2 ton status

    Joined:
    Jan 28, 2005
    Posts:
    306
    Likes Received:
    0
    Location:
    Braselton, Ga
    what do ya mean surge... does it act like you have a cam. Might be a vacum leak. Mine would surge at idle like that and was running real rich. It was the O2 sensor. Hope you figure the problem out!
     
  3. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

    Joined:
    Jun 23, 2000
    Posts:
    7,921
    Likes Received:
    331
    Location:
    Fort McMurray, Alberta
    Yep, give us more details on what you have done, and how it is acting. One of us may have dealt with a similar problem at some point :)
     
  4. jamber2541

    jamber2541 1/2 ton status

    Joined:
    Apr 10, 2006
    Posts:
    424
    Likes Received:
    1
    Location:
    e.p. texas
    plug up every vacuum port on your engine, start it and see how it acts (dont drive) if no problem there then start hooking up one vacuum line at a time and look for changes etc. etc. if there is an initial problem start tightening every single nut and bolt on your intake and throttle body and then move on from there.......worked for me I found the vacuum leak the mechanics could not find.
     
  5. Confedneck79K30

    Confedneck79K30 3/4 ton status

    Joined:
    Oct 1, 2006
    Posts:
    5,384
    Likes Received:
    0
    Location:
    LA
    can try brake clean or carb cleaner to find a vac leak as well
     
  6. southern customs k5

    southern customs k5 Newbie

    Joined:
    Sep 9, 2006
    Posts:
    4
    Likes Received:
    0
    Location:
    georgia
    egr valve stuck open
     
  7. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

    Joined:
    Dec 15, 2002
    Posts:
    15,139
    Likes Received:
    565
    Location:
    Iowa
    Sounds like one I had once, it was a map sensor of maf sensor or whatever ya call that thing.
     
  8. gmc4cw

    gmc4cw 1/2 ton status GMOTM Winner

    Joined:
    Jul 19, 2006
    Posts:
    3,907
    Likes Received:
    0
    Location:
    west chester, Pa
    used starting fluid to find an intake leak once.
     
  9. shane74

    shane74 1/2 ton status

    Joined:
    Feb 12, 2002
    Posts:
    4,100
    Likes Received:
    0
    Location:
    Vancouver, WA
    That' my bet too. I had the EXACT same problem as you w/ my '87 burb. It happened TWICE in less than a year :mad: . Talk about irritating. Do yourself a favor, if it is your EGR, buy an OEM unit. The ones from the parts store are junk. It's worth the extra 10 bucks for a good one.
     
  10. y5mgisi

    y5mgisi 1 ton status

    Joined:
    Aug 11, 2002
    Posts:
    17,156
    Likes Received:
    247
    Location:
    Portland Oregon
    Ok dudes. I just rebuilt the motor. It runs perfect as long as its not idleing. and runs the same iwth the egr hooked up or capped off. uive done the carb clean thing to check for leaks and coame up with nothing.all the vacume lines on it are new cause the old ones where crap. When i put the motor back in i replaced the o2 just cause i thought it would be a good idea and the knock sensor because i couldent get the old one out of the block without destroying it. sence then(this is going to sound stupid and it is) ive replaced the map, TPS, had the injector pod rebuilt, and put a 195 t-stat back in(was runing a 180) I even got the thing to pass DEQ.

    The problem is this. Your cruising around and you come to a stop light. It runs perfect for about 30-45seconds then it starts to run rough about 5 seconds then sonds like its going to die then idles way back up to about 1500 rpm or so and it does that over and over again. You can make it stop by taping the gas pedal real quick but then again it will run fine 30-45 seconds and start the cycle all over again. but like i said it runs great as long as its not idleing.
     
  11. Confedneck79K30

    Confedneck79K30 3/4 ton status

    Joined:
    Oct 1, 2006
    Posts:
    5,384
    Likes Received:
    0
    Location:
    LA
    ive seen explorers do that with bad fuel pump relays...
     
  12. Leper

    Leper 1/2 ton status

    Joined:
    Feb 18, 2005
    Posts:
    4,437
    Likes Received:
    0
    Location:
    Dallas Baby!!!!
    You may want to take a real close look at the dizzy. On my 90 Burb, it was coming apart under the little metal shield. Don't know what its called, but I knew that cracks in it were bad. It would run ok under load, but it wouldn't idle for squat. I put the trail spare for the blaze in it and it was fine.
     
  13. Steve GMC

    Steve GMC 1/2 ton status

    Joined:
    Dec 3, 2005
    Posts:
    247
    Likes Received:
    0
    Location:
    middletown,Connecticut
    same thing happened to our coevette. it was the computer. it would runl ike garbage cold, then when it warmed up it would run better if it wasnt idleing
     
  14. y5mgisi

    y5mgisi 1 ton status

    Joined:
    Aug 11, 2002
    Posts:
    17,156
    Likes Received:
    247
    Location:
    Portland Oregon
    man... i just went out and checked the codes and all i get is code 32 EGR but that is becasue i was driving it with it capped off. Does anyone know of a way to test the computer? and i'll pul the cap and rotor off the dist. and see if anything looks a miss.
     
  15. JpEater

    JpEater 1/2 ton status

    Joined:
    Nov 20, 2005
    Posts:
    299
    Likes Received:
    0
    Location:
    Augusta, Georgia
    Capping off the EGR wont do any good if its stuck open. Sounds like it could be stuck open causing a vacum leak that you can't find with carb cleaner. Pull it off and check it out.
     
  16. y5mgisi

    y5mgisi 1 ton status

    Joined:
    Aug 11, 2002
    Posts:
    17,156
    Likes Received:
    247
    Location:
    Portland Oregon
    ok, what exactly would i be looking for to give me a sign that it was stuck open?
     
  17. WRENCH-HEAD

    WRENCH-HEAD 1/2 ton status

    Joined:
    Dec 25, 2005
    Posts:
    327
    Likes Received:
    0
    Location:
    Littleton, CO
    I've been battling the same problem for a year now. Just started one day and I have yet to figure it out. I'm down to thinking a vacuum leak. If I disconnect the MAP sensor it runs perfect. The techs told me this was because the map sensor is what know if you have a vacuum leak and trys to compensate. So I guess try pulling the vacuum line the MAP sensor and see what happens.

    -Alex
     
  18. lrazer

    lrazer 1/2 ton status

    Joined:
    Oct 3, 2004
    Posts:
    231
    Likes Received:
    0
    Location:
    Mokena, IL
    u check the IAC?
     
  19. k204dr

    k204dr 1/2 ton status

    Joined:
    Aug 27, 2004
    Posts:
    463
    Likes Received:
    0
    Location:
    TN
    yea, the Iac can cause it to hunt, try cleaning it out, or getting a new one. also, you need to remove the egr and make a blockoff plate to check it.
     
  20. mike n

    mike n 1/2 ton status

    Joined:
    Oct 9, 2003
    Posts:
    101
    Likes Received:
    0
    Location:
    New York
    What's the TPS reading at idle?
     

Share This Page