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Thread: 1989 Westfalia Idles too Fast

  1. #1
    Join Date
    Jul 2002
    Location
    Sausalito, CA, USA
    Posts
    6

    Default 1989 Westfalia Idles too Fast

    My 1989 Westfalia (stock engine with about 30K miles after rebuild) idles too Fast, about 1200 RPM when completely warmed up. My smog inspection guy (I live in California) thinks it could be the "Idle Air Control Valve", or possibly a wiring issue or the "Control Module".

    What he is calling the Idle Air Control Valve sits on top of the engine, has a jack for electrical connections and a couple places it plugs in with rubber fittings. He removed the valve and liberally sprayed some lubricant in the openings and reinstalled, but the idle remained high. Also tried moving around wires in the vicinity but that didn't change the idle speed.

    Any advice on how to determine the real problem?

    Thanks!

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  3. #2
    Join Date
    Apr 2012
    Location
    G Town, BC
    Posts
    7

    Default Idle Control Valve

    -if you turn your key on, and the unit is 'buzzing', apparently it should be working. I'm having the same issue with my '86. I bought a reconditioned control valve, tried it, no difference. I also bought a replacement unit for the idle sensor module (?exact name?), but it's located behind the psgr side tail light - follow the large wire underneath air snorkel, reach back there and pull the rectangular unit up to release it from its position. maybe the connection isn't perfect with that. Anyway, replacing that didn't help me either. I've also read about changing ground wires. Especially the main ground strap drivers' side of engine, on the top of the head. Mine was pretty ragged. Next step for me is get to a dealer for a diagnostic reading. I'm down to about 1100 rpm, would like a bit lower. If you need to replace your idle module, or idle control valve, I have one of each for sale.
    Mike in BC


    Quote Originally Posted by antarkosho View Post
    My 1989 Westfalia (stock engine with about 30K miles after rebuild) idles too Fast, about 1200 RPM when completely warmed up. My smog inspection guy (I live in California) thinks it could be the "Idle Air Control Valve", or possibly a wiring issue or the "Control Module".

    What he is calling the Idle Air Control Valve sits on top of the engine, has a jack for electrical connections and a couple places it plugs in with rubber fittings. He removed the valve and liberally sprayed some lubricant in the openings and reinstalled, but the idle remained high. Also tried moving around wires in the vicinity but that didn't change the idle speed.

    Any advice on how to determine the real problem?

    Thanks!

  4. #3
    Join Date
    Apr 2012
    Location
    G Town, BC
    Posts
    7

    Default

    To add to this topic, this summer my Hall Sender went. Looked like it had been JB welded at some point, finally fell apart. Luckily it was miles from nowhere in the desert of northern Nevada... with it replaced, my idle dropped down to 1000 rpm, just where I want it, perfect for smooth, stealthy, walking pace putt-putt-ing through campgrounds, etc

  5. #4
    Join Date
    Jul 2010
    Location
    Snohomish, WA
    Posts
    112

    Default

    The CIS (Constant Idle System) allows air to bypass the throttle plate and by regulating that air the idle speed is controlled. This system is utilized when at idle so the first thing to check is throttle bore cleanliness and idle switch adjustment. If the throttle is dirty then the gap between the throttle butterfly and the bore is reduced, thus reducing the amount of air that can pass at closed throttle. If the switch is out of adjustment and the control module does not know that the throttle is closed then it will not bring the CIS system into action. If that happens, some people are tempted to 'adjust' the throttle and that just upsets the whole system. So, my advice for the first step is to make sure the throttle bore is clean and the basic throttle screw is adjusted correctly.

    Depending on year and engine management system there are various switches on the throttle body so you will have to identify and check accordingly. Once the throttle is set up, warm up the engine and turn all consumers off (AC, electrical etc.). With no load on the engine, pinch off the hose that goes to the CIS valve. The engine should barely run...(on my Yr. and Mdl. it says 880rpm +/- 50 but the engine should idle). Un-pinch the hose and the idle speed should increase and behave properly i.e. when you put a consumer on (AC, headlights etc.) the idle will dip momentarily but then stabilize around 900rpm. The idle will fluctuate when the temperature of the coolant changes so this must be done with a warm engine and no load.

    The other thing to keep in mind is that the throttle switch can appear to be correctly adjusted but act up. On page 24.59 of the Bentley the throttle valve switch adjustment is outlined and it shows a 0.002"- 0.004" feeler gauge to check the 'switching' point of the switch. It is important for this adjustment to be correct or there are drivability concerns that vary depending on how the switch is out of adjustment. Just keep in mind that the switch adjustment is important if you are in that area or working with your idle speed and that temperature can be a factor in this system.

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