Thread: RPM stays up

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  1. #1
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    Default Re: RPM stays up

    My 2000 does the same thing...holds the idle up until you stop. I understand that this is normal. If memory serves me, it has something to do with emissions.


  2. #2
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    Default Re: RPM stays up

    Ditto my 00.After driving a 95 for 6 yrs it took me by surprise, but I guess it is normal.


  3. #3
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    Default Re: RPM stays up

    Check the "bad gas" post by steveb. May be the lower octane gas around these days.


  4. #4
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    Default Re: RPM stays up

    I too have this problem. I have tried just about everything to remedy this condition to no avail. I have replaced the idle speed motor, installed different computers, new intake gaskets, and even a vacuum restrictor to the idle motor. If you re-flash the computer, the problem disappears for a short while, but then returns. It's as if the computer is learning bad information, then trying to compensate for it. The problem seems to plague both stock and modified cars. I have tried to talk with Chrysler engineering about this, and have had little cooperation or interest. Frankly, lately, DC Tech support has been a joke. If you tell DC the car has been modified, they turn their backs completely on the issue. This is a annoying and potentially dangerous problem that DC seems to ignore. If anyone does come up with a fix that actually works, I would sure like to know about it. Until then, expect to burn up some brakes slowing the freeking idle down until the car is completely stopped.


  5. #5
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    Default Re: RPM stays up

    Check intake manifold gasket...problem on 97's.


  6. #6
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    Default Re: RPM stays up

    No doubt this is a sinister plot to sell MORE PARTS and labor by the boys LURKING on the "inside"
    "LURK".... I just love that word.......Thanks Jon B

  7. #7
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    Default Re: RPM stays up

    My 2000 will not return to normal idle if the clutch is in and I am rolling and any speed above 5mph. Once the car almost comes to a stop, the idle drops to normal. I am pretty sure it's normal. I have tested it with the clutch in an rolling down a long hill. The car can stay with a high idle for 2 minutes. As soon as the car comes to a stop the idle drops. Anyone who thinks theirs has a problem should test it in the same way. If your idle hangs once you are stopped, you probably do have a problem.


  8. #8
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    Default Re: RPM stays up

    John Hennessy posted the fix for this not too long ago. I believe it had to do with an added interior tube to one of the vacuum hoses. I'm certain you will all find it if you search on idle problems and as I recall the fix was quite easy to implement.

    Phil


  9. #9
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    Default Re: RPM stays up

    Mine does it as well but only with the a/c on. Since a/c and flat out performance don't usually go hand-in-hand, it's not a problem for me.


  10. #10
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    Default Re: RPM stays up

    Just to satisfy my own curiosity, when (mileage wise) did you folks start experiencing this idle problem? As for myself, I had trouble free operation for about 32,000 miles, of which 16,500 were driven after extensive modification to the heads, TB's, intake & exhaust manifold, cam, and ECU. etc...
    I think if the Mod's were the culprit, they would have shown up much sooner than 16.5K miles. When you re-flash your ECU, does the idle straighten out for about 300 miles then start hanging?Mine does. After re-flashing, the idle will "step down" in about three seconds to the idle position regardless of car speed when decelerating and the clutch in. (This is how the car should behave) After a few hundred miles, the idle will begin to hang at about 1200 to 1500 RPM until the car is completely stopped. No difference with the clutch depressed or not at this point, and even then, it takes 15 or 20 seconds to settle out. The only other way to bring the idle down is to "lug" the motor down to idle. DRB shows all systems OK. yet obviously something is not! I've tried all the "fixes" I know. Any additional Viper Owner or tech experiences concerning this problem would be appreciated. Someone help us fix this problem PLEASE!!!


  11. #11
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    Default Re: RPM stays up

    Jim,

    You and I are very familiar with our similar Viper Idle problems. I continue to have the hanging idle issue as well. The Hennessey restrictor tube did make some improvement. I would still suggest reinstalling the restrictor tube and then manually adjusting up the idle on the TB's

    My problems started right after the Venom package. However, that was pretty close to 32k miles. I also agree that Flashing the PCM does solve the problem - temporarily. Hell, I dont really mind the idle....I just hate the hesitation and sputtering before the car warms up......

    Car runs like a scalded dog....so I guess I should not really complain!

    Regards,


  12. #12
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    Default Re: RPM stays up

    Hi Martin. Your hesitation and sputtering is probably a result of the restrictor. When I replaced the restrictor hose with the stock hose, the "cold" derivability issues mentioned above cleared up. I don't think this (high idle) problem is caused by Hennessey's work or design. There are cars out there with similar symptoms that HMS never touched.


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