Checking the Engine Warm-Up Valve

PROCEDURE

K-Jetronic Fuel Injection System Components 1, 5, 9 – electrical connectors; 2 – O-ring; 3 – fuel line from fuel pump; 4 – fuel return line to fuel tank; 6 – cold start valve thermal switch; 7 – cooling system hose; 8 – engine warm-up valve; 10 – pressure regulator; 11 – adjusting shim; 12 – fuel distributor; 13 – air flow sensor; 14 – fuel distributor plunger; 15 – O-ring; 16 – plug; 17 – mixture control screw; 18 – injector; 19 – intake manifold; 20 – gasket; 21 – cold start valve

After starting, during warm-up, the engine requires a richer mixture. Valve 21 (see figure K-Jetronic Fuel Injection System Schematic), which is in effect a pressure regulator, reduces the pressure acting on the fuel distributor plunger 22. As a result, plate 18 rises higher and moves plunger 22 upward, enriching the mixture. Check the valve with the engine cold in the following sequence: PROCEDURE 1. Disconnect the center high-tension lead from the ignition distributor and ground it. 2. Disconnect electrical connector 9 (see figure K-Jetronic Fuel Injection System Components) from valve 8.

3. Connect a voltmeter to the terminals of connector 9 and crank the engine with the starter. The voltmeter must show a voltage of at least 11.5 V. 4. Switch off the ignition. Connect an ohmmeter to the valve terminals. The ohmmeter must show a resistance of 20–26 Ω; otherwise, replace the valve.