Welcome to Club Hot Rod!  The premier site for everything to do with Hot Rod, Customs, Low Riders, Rat Rods, and more. 

  •  » Members from all over the US and the world!
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and hundreds of thousands of posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

 

Thread: Need help with my 90 Tbird
          
   
   

Reply To Thread
Results 1 to 11 of 11
  1. #1
    joker51's Avatar
    joker51 is offline CHR Member Visit my Photo Gallery
    Join Date
    Oct 2002
    Location
    Mandan
    Car Year, Make, Model: 1949 Ply/ 1979 International Traveler
    Posts
    373

    Need help with my 90 Tbird

     



    My other post on this disappeared so here it is again.
    My engine is running a high idle after acceleration. If I don't touch the pedal it idles fine. But if I rev the engine it doesn't come back down. The return linkage for the throttle is on the spring is fine I have checked all that. When driving the car will go about 40mph without my foot on the pedal, at stop signs it sounds like I am trying to do a break stand with it.
    Is there a vaccuumm that is suppose to bring it back down or something else that might have gone out on it? I only work on carb motors so I am lost on this.
    Thanks for any help.
    1949 Plymouth Club Coupe Still in pieces.
    1979 International Scout Travler with SOA, 345 Engine and 727 AT

  2. #2
    Jerilynne1965's Avatar
    Jerilynne1965 is offline CHR Member Visit my Photo Gallery
    Join Date
    Jul 2004
    Location
    :)
    Car Year, Make, Model: 3 Pontiac T/A's, 1965 Ford F-100
    Posts
    447

    Hey Tim, Let me first say that I don't know my rear from a hole in the ground when it comes to engines. So this probably won't help you a bit ha ha! But, I just went through a very similar issue with my TransAm...pedals not stickin...but the car is revvin and racin down the street doin 35 an accelerating with no help from me whatsoever...I also had issues with stalling and what appeared to be some kind of short (lights flashing etc.) I don't know how it all works together, but turns out I had a bad alternator...once that wuz replaced ...she runs like a dream....
    You miss 100% of the shots you never take

  3. #3
    Jerilynne1965's Avatar
    Jerilynne1965 is offline CHR Member Visit my Photo Gallery
    Join Date
    Jul 2004
    Location
    :)
    Car Year, Make, Model: 3 Pontiac T/A's, 1965 Ford F-100
    Posts
    447

    Talking

     



    OK, yeah, now that I think about it...I can't believe I actually wrote that post to an experienced engine person LOL...to quote the Grinch "I'm an Idiot....echo echo echo...You're an Idiot...echo echo echo"...Good luck anyway!
    You miss 100% of the shots you never take

  4. #4
    drg84's Avatar
    drg84 is offline CHR Member Visit my Photo Gallery
    Join Date
    Sep 2003
    Location
    Dansville
    Car Year, Make, Model: 1996 Aurora Autobahn edition
    Posts
    1,201

    OK, assuming that your motor is the plenum-style 5.0, im going to go with this. The idle is mostly controlled by the air intake past the throttle plates. As it seems to increase upon heating, my guess would be that either your plates are sticking due to improper oiling(pcv does a good job at this) or there is something either scoured or caught on your plates. Also, check for vacum leaks on the rear of the plenum. Give more info(motor, turbo?, ect) and we can help more.
    Right engine, Wrong Wheels

  5. #5
    joker51's Avatar
    joker51 is offline CHR Member Visit my Photo Gallery
    Join Date
    Oct 2002
    Location
    Mandan
    Car Year, Make, Model: 1949 Ply/ 1979 International Traveler
    Posts
    373

    3.8 V6 stock engine.
    Someone had mentioned to me that there was a motor or something that controls the idle, Does anyone know what this is?
    ANd Jerilynne, don't worry about it, If I was that experienced with the FI and EFI engines I wouldn't have asked the question. A carbed motor I can figure my way around and fix, but am lost with this and any help is appreciated.
    Last edited by joker51; 09-08-2004 at 06:38 PM.
    1949 Plymouth Club Coupe Still in pieces.
    1979 International Scout Travler with SOA, 345 Engine and 727 AT

  6. #6
    Matt167's Avatar
    Matt167 is offline CHR Member Visit my Photo Gallery
    Join Date
    Jan 2004
    Location
    Prattsville
    Car Year, Make, Model: '51 Chevy Fleetline and a Ratrod project
    Posts
    4,990

    Originally posted by joker51
    3.8 V6 stock engine.
    Someone had mentioned to me that there was a motor or something that controls the idle, Does anyone know what this is?
    ANd Jerilynne, don't worry about it, If I was that experienced with the FI and EFI engines I wouldn't have asked the question. A carbed motor I can figure my way around and fix, but am lost with this and any help is appreciated.
    Well, if ur better with carbed motors, why not drop in a carbed 5.0 and be done with it? . The only thing I can think of is sticky pedal. My brothers 1990 Ranger 2.8 V6 did this, it had some kind of gaurd for the throttle linkage and the cable got all gunked up and it would stick but if you let it set a day or just a while, it would go back, fixed it with degreaser and a rag, just a thought.
    You don't know what you've got til it's gone

    Matt's 1951 Chevy Fleetline- Driver

    1967 Ford Falcon- Sold

    1930's styled hand built ratrod project

    1974 Volkswagen Super Beetle Wolfsburg Edition- sold

  7. #7
    joker51's Avatar
    joker51 is offline CHR Member Visit my Photo Gallery
    Join Date
    Oct 2002
    Location
    Mandan
    Car Year, Make, Model: 1949 Ply/ 1979 International Traveler
    Posts
    373

    Not a sticky pedal, I can play with the linkage under the hood and it snaps back just fine. Thats what confuses me so much on this. I was wondering if there is an idle motor or sensor or vaccumm that controls it that could be screwed up.
    1949 Plymouth Club Coupe Still in pieces.
    1979 International Scout Travler with SOA, 345 Engine and 727 AT

  8. #8
    Jerilynne1965's Avatar
    Jerilynne1965 is offline CHR Member Visit my Photo Gallery
    Join Date
    Jul 2004
    Location
    :)
    Car Year, Make, Model: 3 Pontiac T/A's, 1965 Ford F-100
    Posts
    447

    You were asking about sensors...i'm sure you already tried this...but I did a Google search for "high idling" on the 90 t bird...came up with a few articles that talked about something called a Mass Air Flow Sensor ---- but the symptoms it described seemed more geared toward lower idling...sputtering etc. & only way to fix it is to replace the sensor....

    But also came up with a number of articles and service bulletins from Ford about the "Throttle Air Bypass Valves"...sypmtoms included High or Low idling...
    You miss 100% of the shots you never take

  9. #9
    joker51's Avatar
    joker51 is offline CHR Member Visit my Photo Gallery
    Join Date
    Oct 2002
    Location
    Mandan
    Car Year, Make, Model: 1949 Ply/ 1979 International Traveler
    Posts
    373

    Thanks JeriLynne I appreciate the help and the effort it took you to look those up for me
    1949 Plymouth Club Coupe Still in pieces.
    1979 International Scout Travler with SOA, 345 Engine and 727 AT

  10. #10
    The Al Show's Avatar
    The Al Show is offline CHR Member Visit my Photo Gallery
    Join Date
    Nov 2002
    Location
    .
    Car Year, Make, Model: .
    Posts
    631

    I'm like you Tim. I don't work on modern engines.
    I think Jerilynne is on the right track. The idle is controlled by a computer. The sensors tell the computer what's going on. A bad sensor will give the computer the wrong input. The MAF sensor is the one that goes bad more often but there are other sensors on the exhaust manifolds and catalytic convertor too. I think a MAF sensor costs less than having a technition ( remember when they were called mechanics?) hook it up to a diagnostic computer. Or it might just need a new air filter.
    " Im gone'

  11. #11
    cobra13 is offline CHR Member Visit my Photo Gallery
    Join Date
    Nov 2004
    Location
    noble
    Posts
    26

    hey check the IAC valve Idle air control valve....it may be bad or gunked up

Reply To Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Links monetized by VigLink