| Trouble | Cause | Correction |
| Engine does not start, fuel pump is not running. | Defective pump connections, pump relay or connections. Check pump connector for good condition. | Check if pump relay is functioning (switch ignition on and off, listen for relay noise). If necessary, use voltmeter. |
| Pump relay receives no current at terminal 86 (12V) because main relay is not functioning or wire is defective. | Check with voltmeter. Repair open circuit. |
| Pump relay shows 12 volts at terminal 86, but terminal 85 has no ground. | NOTE: Relay is active for only about 1- 1 1/2 seconds after the ignition has been switched on. Check with voltmeter; relay is wired from ground through control unit. Do not connect terminal 85 to ground without first disconnecting wire 19 leading to the control unit, otherwise the control unit will be damaged. If no ground is available to wire 19 (switch ignition on and off), replace control unit. |
| Engine does not start, fuel pump is running. | Connection from wire harness (wire 18) to starter terminal 50 is defective. | Check with tester with starter running. |
| Operator' s problem: Engine does not receive sufficient amount of air for starting. Cold start system defective. | Start with wide open throttle. Check thermoswitch and cold starting valve, possibly spark plugs as well, if overrich mixture is encountered (wet or carbon fouled spark plugs). See 1.1-2/7, test step 19. |
| Open circuit in wire connection of temperature sensor. | Check wires. Replace temperature sensor. |
| No pressure buildup in fuel main line (compressed fuel hose or defective pressure regulator). | Check pressure with gauge: 1.96-2.04 bar
(1.96-2.04 atm) when starter is running.
Replace pressure regulator if necessary. |
| Defective diaphragm chamber in pressure sensor. | Replace pressure sensor. |
| Engine starts when cold but stops again. | Wire connector for trigger contacts in distributor not connected or wire broken. | Connect tester and go through test steps
8,9, 10, 11, 11a (EFAW-tester) resp. 14
(VW1218). If necessary, replace wire
harness or trigger contacts. |
| | Defective trigger contacts. | Replace. |
| | Also see "Engine does not start". | |
| | Defective pressure sensor. | Replace. |
| Engine dies when car is in motion (usually pre- ceded by misfire). | Trigger contacts have excessive resistance or are dirty. | Connect tester. If test steps 8 and 9 (EFAW tester) or 14 (VW 1218 tester) show malfunctions, replace trigger contacts in distributor. |
| Defective connectors. | Check. |
| Entire system malfunctioning. Pump relay failing occasionally. | Loose connection in power supply line of pump or control unit ground. | Check pump relay and associated wires with voltmeter (follow wiring diagram). |
| Engine running badly. one cylinder not working. exhaust trails white smoke, | Stuck injector. | Replace. |
| Bad connection in injector winding or injector. | |
| Engine misfires due to causes other than the ignition system. | Loose connections, but also ground connections, in injectors (ground- related problems cause two injectors to malfunction). | Check connections, replace injectors if necessary. |
| Corroded or loose ground connections in the electrical system. | Check ground connections for firm seating and attachment; battery ground strap, ground strap connecting transmission with frame, and regulator ground. |
| Check if problem can be traced to the ignition system. Otherwise it may be periodic voltage drop (Voltage I and II) in control unit (loose connection also in multiple connector in control unit. | Check continuity in wires 16 and 24 with the aid of voltmeter. |
Engine does not produce its full power.
Poor power output and poor power transition. | Defective pressure sensor.
Regulating flap for crankcase vacuum binding.
Insufficient injection quantity over the entire range due to fuel remnant deposits on injectors. | Replace.
Free up.
Replace injectors (injectors cannot be checked with shop tools).
|
| Excessive fuel consumption. | Defective temperature sensor or high contact resistance, | Check connecting wires. Connect tester and go through steps 1-12 (EFAW-tester) or 1-13 (VW 1218 tester). Replace defective parts after possibly performing supplemental tests. |
| Considerable rpm surging during idling (between 1000 and 2000 rpm). | Leak between auxiliary air regulator and intake distributor. | Check. |
| Leak at throttle valve housing. | Replace gasket between throttle valve housing and intake distributor, possibly reposition. |
| Leak in connecting houses between the intake distributor and intake manifolds. | Poorly seated hoses, possibly requiring replacement. |
| Uneven idling, very poor transition during acceleration. | Engine out of adjustment. | Check and readjust ignition timing, valve clearance, and idle speed. |
| Mixed up injector groups. | Check if connections are properly attached to
ignition distributor and injectors. |
| Loose vacuum hose connections. | Firmly connect vacuum hoses, replace if necessary. |
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