Test Point 9 - Throttle Switch
TEST POINT 9Throttle Switch - Idle Contact
The idle switch is operated by a drag lever via the accelerator linkage. When operated, the idle switch must have already switched before the throttle valve opens after a specified dead travel of approx. 1 mm.
1. Start and run engine at idle speed.
Press accelerator linkage by hand approx. 1 mm (dead travel) slowly, without that the throttle valve opens.
Idle speed should now increase approx. 500 rpm and ignition timing must be advanced (approx. 12° before TDC)
If not, check microswitch and its adjustment.
2. Check idle switch with a power flow tester or ohmmeter.
Pull off idle switch plug and connect tester.
Display: 0 ohm (power flow)
Move throttle valve by hand (approx. 1 mm) slowly.
Display: infinite ohm (switch open)
3. Adjust idle switch.
Push drag lever down until it rests on throttle valve lever (dead travel). Throttle valve must rot yet be moved.
Adjust distance between switch and drag lever to 0.2 mm with a feeler gage blade.
4. Check coasting shutoff.
Run engine at idle speed.
Bridge contacts on idle switch plug with a test lead.
Increase engine speed to approx. 1300 rpm.
Engine begins to surge (cutting off of injection signal).
If not, check wires to control unit according to wiring diagram or replace control unit if necessary.
Throttle Switch - Full Load Contact
1. Start and run engine at idle speed.
Pull off plug (9) on full load switch and bridge contacts on plug with a test lead.
Engine speed should drop.
If not, check wires according to wiring diagram.
2. Check full load switch with power flow tester or an ohmmeter.
Pull off plug on full load switch and connect tester.
Display: infinite ohm (switch open)
Move throttle valve to full load (wide open).
Display: 0 ohm (power flow)
3. Replace full load switch.
Switch does not have to be adjusted.
When installing switch, turn against left lock in slots and tighten mounting screws.