13 41 000 a - Idle speed control valve - remove and install < 13 - Fuel System < BMW 728 - 745i
From model '83
VALVE (Since 1985 Models)

Pull off plug (1).
Disconnect retaining strap (2).
Pull off idle control valve on hoses and remove.

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Check code number (1)*.
Check idle speed*.

* See Specifications and Nominal Value Microfiche
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Whether or not the idle control valve is
running can be felt by taking hold of valve
with a hand (cycled power supply).

Mechanical Test:
The rotating piston (1) in the idle control valve
must move when turning the idle control valve

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Electric Test:
Measure resistance between terminals (1 and 3).
Nominal value: approx. 40 ohms.
Measure resistance between terminals (2 and 1)
or (2 and 3).
Nominal value: each approx. 20 ohms.

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Dynamic Test:
Remove idle control valve.
Plug remains connected.
Open rotating piston (1) completely, or close.
Turn on ignition.
Rotating piston must take on a position of
approx. 50% the cross section opening and
stay there.

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Testing sequence on engine with pulsating
idle speed but idle control valve (tested) in
perfect condition.

Engine at operating temperature.
No false intake air.
Idle speed CO level *) correct.
All consumers (Light, aircond. eg.) switched off.
Connect BMW Service Test of Digital-Tester.
There is no dilution on eng. oil.

Engine oil dilution means = Gasoline in Eng. Oil,
caused through cold ambient temp. and mainly
stop and go traffic.

*) see nominal Values
Plug Universal-Adapter between DME-Control
Unit and Engine Wiring-harness.
Connect plugs (3/5/2) together (eng. idle- and full
load contacts closed).
Engine idling.

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If engine idle rpm.>= 750/min. proceed as
outlayed in troubleshooting.
(fault is not on idle control system).

If engine idle rpm.<= 750/min. the basic throttle
setting has to be altered. Loosen screw (1).
Adjust connecting plate (2) with stop (3) until
idle rpm. is 780 ... 800/min.

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If the fault is not corrected, the throttle-flap setting has to be put in the
original state.

Cars with active carbon filter ventilation (US/J).

Even if the throttle-flap is slightly opened there must be
no vacuum on hose (4) - Check -

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