Results 1 to 6 of 6

Thread: T-stat?

  1. #1
    Join Date
    Apr 2005
    Location
    Stoney Creek
    Posts
    667
    Time Online: 1 Wk 18 Mins 20 Secs
    Avg. Time Online: 34 Secs
    Rep Power
    13

    T-stat?

    2002 Saturn SL1

    I read somewhere that if your t-stat is shot then the fuel:air ratio will most likely be off and this can cause stumbling when you hit the gas. Is this true?

    I have pretty severe stumbling when I hit the gas at all if I do not downshift first. This means I am almost always in too (numerically low) of a gear revving high to avoid this problem.

    Does this sound like something that a T-stat could affect? the other diagnosis is the Intake manifold gasket. But the last mechanic that looked at it said that there is nothing wrong with it.
    Do either of these make sense? any other ideas?


    Very strange though, it does not stumble when downshifting. Just when giving it gas (eg. when going slow in 3rd, but could be in a very high 2nd)

    thanks
    93 YJ
    4" rough Country Susp. lift 2" shackle lift 2" Body Lift, TJ Flares
    35" M/T's
    Cobra CB with no antenna (thanks Grimsby)

  2. #2
    Join Date
    Jan 2007
    Location
    Waverley
    Posts
    237
    Time Online: 1 Day 8 Hrs 8 Mins 51 Secs
    Avg. Time Online: 6 Secs
    Rep Power
    11
    A late model saturn like yours should set very specific codes for that type of senario. Always start with DTC's if they are available. If not, a realtime data stream may give you clues to whats causing the problem. As far as defective thermostats go, yes it could have a negative effect on driveability. However, its just one thing on a very long list of potential suspects. Regardless, an easy way you could monitor its operation is a coolant temp guage if equiped. If your serious about fixing the problem your going to need more information about the senario. Having the proper diagnostic tools will provide you with all the clues to the puzzle. Without them your just going to be throwing parts at it hoping for results. Good luck with it.

  3. #3
    Join Date
    Apr 2005
    Location
    Stoney Creek
    Posts
    667
    Time Online: 1 Wk 18 Mins 20 Secs
    Avg. Time Online: 34 Secs
    Rep Power
    13
    I am going to need someone to diagnose the problem for real. I could just start replacing one part at a time but that could be pointless.
    Anybody know someone that could do an honest diagnosis? I can most likely do the work myself but want to know what has to be done.
    So far on the list of possibilities I have:
    - Intake manifold gasket
    - ECTS sensor
    - fuel pump
    - fuel filter
    - (maybe but prolly not) clogged CAT.

  4. #4
    Join Date
    Sep 2007
    Location
    Ottawa Area
    Posts
    4
    Time Online: 7 Hrs 4 Mins 16 Secs
    Avg. Time Online: 1 Secs
    Rep Power
    0
    The problem you are having is most likely caused by the coolant temperature sensor - located on the back side of the head (opposite of belt). I had to change one on my Brother's car a couple of years ago. The part is only $10-20 bucks from the dealer.
    I work at a Gm dealer in Ottawa, this is just my $0.02 worth.
    Cheers

  5. #5
    Join Date
    Jan 2004
    Location
    Thornhill / Bowmanville, On
    Posts
    3,736
    My Mood
    Stressed
    Time Online: 1 Wk 4 Days 3 Hrs 23 Mins 35 Secs
    Avg. Time Online: 54 Secs
    Rep Power
    17
    Why not have the dealer ( or reputable shop ) diagnose it for you...
    Give them an hour to diagnose it and see if they can tell you whats wrong?
    The initial diagnosis is 1 hour of labour ( most places ). It would be a good place to start rather than just replacing parts....


    The reason that I dont think its the thermostat ( and going on what you described as your problem ) is that the thermostat keeps the engine running at operating temperature. If it is not reaching operating temperature, the thermostat is most likely stuck open. The computer is constantly reading this and when it is reacting to this info, it will feed more fuel into the system to make the engine warm up faster.
    What will make the car stumble is if the rpm is too low when you mash the peddle to go faster...
    As well, when was the last tune up? Have you ever considered having the intake system cleaned?
    You will need more diagnosis before you start throwing money at it....

  6. #6
    Join Date
    Jun 2005
    Location
    Burlington
    Posts
    5,009
    Time Online: 1 Mth 3 Wks 5 Days 8 Hrs 29 Mins 23 Secs
    Avg. Time Online: 4 Mins 37 Secs
    Rep Power
    18
    HRJ and Dyno are both right in that more information is required on this one. Historically, based on drivability issues that I've seen in the shop, a coolant temp sensor CAN cause your issues, and GM is rather famous for having them fail. At ~$20, it's your call to decide if you're just going to throw parts at it. Ideally, I would hook a datastream tool to your OBD connector and see what the computer is seeing. And, as stated, a simple tune up w/wires may be in order. Wires have a habit of failing in cold/damp weather, which we've been experiencing. Idle will be okay due to the low load on the motor, but if you try to accelerate the lack of ignition will become more pronounced.

    If you're mechanically inclined, I would begin with plugs & wires, coolant temp sensor and thermostat. These are all wear items and must be replaced on a regular interval anyway, so it's not wasting money. Also, if it does not fix your problem, it is less items the inspecting garage can recommend to you as repair requirements. Often, to cover their ass, a shop will recommend a blanket of repairs instead of isolating exactly what the fault it. Often it's in the owners best interest to have all the repairs done, but was not required at the time to eliminate the immediate issue.

    It is in your best interest in having a shop or reputable mechanic diagnose this issue for you, IMO. Throwing money at it blindly often adds more aggravation when you eventually do bring it in.
    Last edited by Noltz; 01-23-2008 at 06:31 PM.
    ....-Noltz
    '91 Frankenheep Edition. 4.0, 4" BDS, Richmond 8.8, 35" KM2's, Titan 12k, ... gone.
    '95 4Runner SR5. Air-Lift bags, OBA & 8K Winch, DD... gone.

Posting Permissions

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