Cold Start Injector: Testing and Inspection

Motronic ECU Harness Connector (pin # Locations):

1. With the engine cold (coolant temperature below approx. 20~C/68~F), disable ignition coil by disconnecting electrical connector from power output stage. If engine is already warm, remove coolant temperature sensor and immerse sensor tip in ice water until sensor is sufficiently cooled, or disconnect sensor and bridge terminals of sensor harness connector with a 1/4 watt 5K ohm resistor to simulate approx. 0~C/32~F.

2. Remove cold start valve from intake manifold, leaving fuel hose and electrical connector attached, and place valve in suitable container to catch fuel.

Cold Start Injector:

3. Turn ignition switch to "start" position and crank engine for 10 seconds while observing spray from cold start valve.
- Cold start valve should spray a uniform cone shaped mist of fuel for the period of time shown in the diagram, depending on the temperature of the coolant temperature sensor.

4. When valve stops spraying, dry off tip and check for fuel leak. Tip of valve should remain dry. If not, replace valve.

If valve did not spray, connect LED test light between terminals of cold start valve electrical connector and repeat step 3. LED should light or flash (if connected with proper polarity) for the period of time shown in the diagram. If LED does light or flash but valve did not release a spray of fuel, replace valve. If LED did not illuminate, check for:
a. Open circuit between cold start valve connector terminal #1 (Blu/Blk wire) and fuse relay panel.
b. Open or grounded circuit between cold start valve connector terminal #2 (R/Blk wire) and ECU terminal #16.

If no wiring problems are found and LED still does not light or flash, ECU is faulty.