AD07.52-S-3001A | PEC fuel injection and ignition system diagnosis operational check actual values (engine) | 5.5.97 |
ENGINE 111.948 /978 in MODEL 638
Fuel injection and ignition system (PEC) diagnosis, previous knowledge | |||
Function check | |||
Actual value no. | Actual value | Specified value | Possible cause/Remedy |
| Engine coolant temperature | > 80 °C | |
| Engine speed | 75050 rpm | |
| Injection time | 2.1–2.7 ms | |
| Lambda control | 010 % | In the event of a complaint the Lambda control must be measured at idle speed and at 2500 rpm with the purge line (to engine) disconnected and sealed. |
| Throttle valve angle | 0.3–2.5 ° | |
| Intake manifold absolute pressure (A/C compressor off, no drive stage) | M111.948: 55050 mbar M111.978: 60050 mbar Value applies to an ambient air pressure of approx. 970 mbar | |
| Oxygen sensor voltage (fluctuates around 300 mV after 2 minutes) | –200 to +1000 mV | |
| Idle speed self-adaptation Idle speed basic position: Idle speed: Idle speed: | 00.2 ms 0.0 ms < 0.0 ms (neg. value) > 0.0 ms (pos. value) |
Fuel mixture has a tendency towards "rich" Fuel mixture has a tendency towards "lean" |
| Part-load self-adaptation factor Part-load basic position Part-load factor: Part-load factor: | 0.85–1.15 1.0 < 1.0 > 1.0 |
"Rich" tendency "Lean" tendency |
| Ignition advance angle The ignition advance angle is also used to stabilize idle speed and therefore in an extreme case the ignition advance angle may briefly deviate 10° from the specified value. | 55° CKA before TDC | |
| PEC resistance trimming plug | ||
| Selector lever position | Depending on selector lever position | |
| Inertia fuel shutoff (closed throttle position) Engine speed > 2100 rpm (closed throttle position contact closed) The engine speed threshold is variable and is dependent on manual or automatic transmission, engine coolant temperature, engine load as well as number of ignitions. | Display: OFF Display: ON | |
| Ignition coil combustion period | 1.7-2.3 ms | |
| Ignition coil combustion voltage | 30-35 V | |
| Ignition coil fault counter | < 50 | |
| Exhaust gas valve (idling) | Display: CLOSED |