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Start-up High Idle Problem

Discussion in '80-Series Tech' started by SUMOTOY, Jul 1, 2005.

  1. SUMOTOY

    SUMOTOY

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    Gents:
    My 94 FZJ80 appears to have an issue on startup. It fires right up no problem, but within 5 seconds, my fast idle is somewhere in the 1800rpm range. No other issues, after some time it returns to a normal idle. This doesn't appear to be a cold start issue either, since it happens after sitting for a couple hours as well. Doing some brake service on a friend's '93, his starts and fast idles around 1100. Is there any adjustment or sensor I should be looking at specifically to put this down at a more reasonable level.

    My concern is the oil pressure can take 10 seconds to get up to pressure, during which time I have 6cylinders in hyperdrive.

    Thanks in advance for any insight to this issue.

    Scott Justusson
    '94 FZJ80 (TJM is on!)
    '87 4R turbo
     
  2. whodat

    whodat

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    does it rattle too? the high rpm start with rattle has been linked to a carbon buildup. do a search on startup rattle if you have this issue.
     
  3. Vitesse_6

    Vitesse_6

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    Sounds like mine, It idles about 1700 till it warms up(emission*sp reasons)Then it drops to 650 or so, From what I have been told it is very normal to have this high idle, If it is erratic after it drops sown there is a issue with the throttle body. IIRC Toyota oil filters have a valve or something in them so they dont let the oil out, So there should be oil in the crank and what not but the oil pressure dosnt show for a few seconds, Could be the perssure guage is measured elsewhare?!?
    Mine has the rattle too.
    Good luck
     
  4. SUMOTOY

    SUMOTOY

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    Thanks for the responses! Glad I'm not the only one. I occasionally (very rarely) do get the startup rattle. I use the factory toyota LC filter always. Yes, the oil pressure takes a while to get up to pressure, which is why this high idle concerns me. 1700 rpm with low oil pressure makes me wince a bit....

    Scott Justusson
    94 FZJ80
     
  5. landtank

    landtank SILVER Star

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    I've mentioned this before and I'll post it up here again. Ever since my valve lash adjustment the startup rattle has been totally eliminated.

    It's been near 2000 miles since done so I'm thinking it's pretty much taken care of.
     
  6. cruiserman

    cruiserman

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    I doubt that. My rig rattled right after the rebuild. No carbon in the cylinders at that time. Also, valves were adjusted to mid spec, and they are still mid spec.

    I've been trying to get the o-ring fix to work, and I've not had any luck yet. Stupid o-rings get squished.
     
  7. snowwolfwarrior

    snowwolfwarrior

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    Just like to add, the last few days I have been parking my LC on a forward sloping hill, and in the morning when starting, there is a lot less rattle on start up.
     
  8. semlin

    semlin discouraged user

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    all i know about start up high idle is that it is somehwere in the t-body or throttle cables. removing the throttle body and replacing it can temporarily fix it for a few weeks. i found this out after removing the t body to try to fix my egr. even though i didn't touch the t-body the start up idle was 1200rpm for two weeks afterwards. same thing after i removed and cleaned the t-body. i wonder whether just unplugging the tps and iac sensors might do it. experiment coming.

    i eliminated start up rattle completely for two years with small good filter and mobil 1 10w30 or 5w30. recently switched to rotella synthetic 0w40 and small good filter and have momentary start up idle maybe one day in three. however, now my main seal doesn't leak anymore. what to do?