Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Cars & Trucks (https://www.askmehelpdesk.com/forumdisplay.php?f=41)
-   -   RPMs stay high when I stop. (https://www.askmehelpdesk.com/showthread.php?t=110781)

  • Jul 17, 2007, 09:58 AM
    L-001-06-H
    RPMs stay high when I stop.
    Well, just got my first stick a while ago... been driving it, and I find that when I get it up to about 4500 RPM, and end up slowing to a stop, it usually only drops to about 3000, until I downshift into first (for stops) and let out the clutch... then, it drops to about 1500 or 2000, where it's soposeto be and takes of just fine... it only does this sometimes, not all the time, and I'm wondering if it's a problem. My last car was an automatic, and I ended up throwing a rod, so this worries me a little. Most of the time though, it drops right back down when I deaccelerate. Any ideas on how to fix this if it is a problem, would also be appreciated.
  • Jul 17, 2007, 05:30 PM
    CaptainRich
    What are you driving: year make and model? Mielage, recent repairs, etc...

    Help us help you.
  • Jul 17, 2007, 06:01 PM
    L-001-06-H
    Quote:

    Originally Posted by CaptainRich
    What are you driving: year make and model? Mielage, recent repairs, etc...

    Help us help you.

    94 saturn, sc1.

    It's a 5 speed, all stock parts (for now), repressed a wheel bearing, two new tie rod ends, and a new ball joint. New rotors, new front break pads, and I'm running it with premium gas, 5 W30 natural oil. The clutch needs adjustment, but it works for now. Shifts just fine, when I'm not tryign to downshift too early, but that's only into first...
  • Jul 18, 2007, 05:34 AM
    CaptainRich
    Mileage? Overall condition under the hood?

    High idle frequently comes from vacuum leaks associated with fuel delivery and emissions control.

    Safety is paramount. There are many moving parts on a running engine that may not be apparent while it's running. So start looking while the engine is OFF.

    Look at the vacuum lines on the engine, running seemingly to and fro, to see if any of them have come loose or have broken/dryrotted.

    Check those lines and let us know.
  • Jul 18, 2007, 10:05 AM
    L-001-06-H
    Quote:

    Originally Posted by CaptainRich
    Mileage? Overall condition under the hood?

    High idle frequently comes from vacuum leaks associated with fuel delivery and emissions control.

    Safety is paramount. There are many moving parts on a running engine that may not be apparent while it's running. So start looking while the engine is OFF.

    Look at the vacuum lines on the engine, running seemingly to and fro, to see if any of them have come loose or have broken/dryrotted.

    Check those lines and let us know.

    Forgot the milage, under 200,000 over 100,000, and it's great under the hood. My uncle and I worked on it, he useto be a marine mechanic, and we checked all the lines and valves, we're prety good there, unless we missed something... it only does this sometime, that's the weird part... sputters SLIGHTLY when I turn it on though sometimes, but then idles out...

    I did find out there is something up with the 'quad driver imput module' (I think is what it's called), it's a chip that works with the injection system, and it does need to eventually be replaced... think that could cause it?
  • Jul 18, 2007, 10:35 AM
    CaptainRich
    It's not always the easiest or cheapest thing. But now the preliminary stuff has been checked. Now it comes time to get to the technical stuff.
    Possible throttle position sensor worn? Or idle air control valve sticking? (This can sometimes be cleaned and buy some time)

    To clean it you need some tools and some throttle plate/carburator cleaner, and some rags. After the engine is warmed up, remove the air cleaner assembly (you are going to access the throttlebody) Now, while bringing the idle up slightly, spray in short bursts, into the throttlebody area. Not just the plate iteslf, but also look for the opening that houses the idle control valve, and clean here, too. All the while keep the engine running to keep that valve open and moving. Let the engine run at idle until stable and check for results. If that works, even for a little while, at least you know you're headed in the right direction.

    I would recommend a qualifed certified shop or dealer. I could guess all day, but without the car in front of me and the right tools to access the vehile on-board data, it would still be guessing.
  • Jul 18, 2007, 10:39 AM
    L-001-06-H
    Air filter is fine, we did have to replace an air something sensor, but I'll have the shop check these things out when I take it in to get my tires ballanced and my clutch and
    e-break adjusted. And thanks for your time friend.
  • Jul 19, 2007, 09:59 PM
    L-001-06-H
    Update: I've been driving it hard to get the RPM rate up there, and when it does that, I can smell gas... the quad driver imput thing that needs to be replaced (far as I was told) controls the injection system, could that explain the smell and the RPM rate?

    Also, would getting that fixed make it accelerate a bit faster? I think I could get it 0-60 in 9sec with just a tiny bit more percice injection settings... and the voltage was off by a bit when me and my uncle tested it... can't remember what it was though...

  • All times are GMT -7. The time now is 09:09 AM.