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Thread: Hi Idle!

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    Member compyelc4's Avatar
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    Default Hi Idle!

    Hi Idle!

    I have a slight problem and could use some advise.

    I have a highly-babied '95 with 48k miles. She runs strong and sets no codes. Here is the problem: Every once in a while on a cold start she'll start on the first revolution and goes to normal high-idle until she warms up. This usually take about 5 minutes in warm weather. As I'm waiting at the first stoplight I notice the idle is about 200 RPM too high. High enough that I have to press on the brake just slightly more than usual to hold it still. Goosing the gas pedal a few times does not lower the RPM to its normal 650 RPM as we used to do with carb. engines. A couple of times I've gotten out, opened the hood and "tweaked" the throttle cam a little and even tried pushing the throttle plate toward the stop but this does not help. The only thing that helps, and this is 100% of the time, is to shut her down and restart. It then goes to normal. Any clues about this other than cleaning the throttle body which I have not done in about 20k miles? I'm thinking it may be mechanical but maybe electrical. Reminder: no codes and idle, normally, is just fine.

    Thanks
    Ted

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    I'd consult the service manual's troubleshooting info in re: rough or unstable idle.

    You can try removing the IAC and cleaning its pintle and seat but do not imerse the IAC in solvent. A problem IAC is one of many causes of unstable idle.

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    Member Schrade's Avatar
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    IAC, TPS, or carbon behind butterfly.

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    Member compyelc4's Avatar
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    Thanks guys. I'll check out these sources and report back.

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    Member tmkassin's Avatar
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    Quote Originally Posted by compyelc4 View Post
    Thanks guys. I'll check out these sources and report back.
    You might want to look for a vacuum leak too.

  6. #6
    Member compyelc4's Avatar
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    tmkassin,

    Thanks for your suggestion too. My question to you is: I know a a vacuum leak could bring on high idle but 1) I think that would be a high idle all the time. Mine is only sometimes. and 2) upon restart my idle goes to normal. Wouldn't a vacuum leak react differently?

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    I will look in my FSM tomorrow. It could be tied to a relay that resets when you restart the motor.

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    Member compyelc4's Avatar
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    tmkassis-

    Thanks. I would really appreciate that.

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    Hi I brought my FSM home tonight to try to look up how to test your vacuum lines. The test is in volume 2 and I only brought volume 1. It is called Air Management Functional Test. I will have more details tomorrow.

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    Member compyelc4's Avatar
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    tmkassin-

    You are too much. I thank you and would do that for someone else if I could.

    Thanks again.

    PS- I do have a vacuum gauge and know how to use it so the info will be quite helpful.

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    Quote Originally Posted by compyelc4 View Post
    tmkassin,

    Thanks for your suggestion too. My question to you is: I know a a vacuum leak could bring on high idle but 1) I think that would be a high idle all the time. Mine is only sometimes. and 2) upon restart my idle goes to normal. Wouldn't a vacuum leak react differently?
    Vacuum leak makes idle lope like a Duncan yo-yo. 30 year old lawnmower, or a new car on the lot - same loping idle. Vacuum leak will NOT steady idle.

    Steady high idle could be TPS...

  12. #12
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    Quote Originally Posted by Schrade View Post
    Vacuum leak makes idle lope like a Duncan yo-yo. 30 year old lawnmower, or a new car on the lot - same loping idle. Vacuum leak will NOT steady idle.

    Steady high idle could be TPS...
    There are several pages I would like to send you. Do you have access to a fax?

  13. #13
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    Quote Originally Posted by tmkassin View Post
    There are several pages I would like to send you. Do you have access to a fax?
    You can email it if you want - I think it's active in my profile. If it's FSM stuff, post up the sections/numbers - I got mine here, and they're pretty similar for LT1. If a vac leak makes a steady high idle, I wanna' see this...

    I just changed my email to 'visible', so however you want. But post it up; if I'm wrong, won't be the first time (or last).

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    Member compyelc4's Avatar
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    tmkassin-

    Thanks. Try this fax: 937/259-7867. That's my work fax. Please let me know when you fax so I won't be checking the fax every 5 minutes.

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    Quote Originally Posted by compyelc4 View Post
    tmkassin-

    Thanks. Try this fax: 937/259-7867. That's my work fax. Please let me know when you fax so I won't be checking the fax every 5 minutes.
    I will send it tomorrow morning

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