Diagnostický případ

Opravené vozidlo

Autoopravna Václav Kačírek

Jazyk případu:

Opel Sintra bad starting

22.09.2006 | aktualizováno 15.02.2007 0:00:00 0 6173x

Informace o vozidle

VIN:	4GDDUO399WD338931
Výrobce:	Opel
Model:	Sintra
Rok výroby:	1999
Kód motoru:	2.2 DTI 16V
Typ motoru:	X 22 DTH
Výkon (kW):	85 kW
Převodovka:	Manuální
Palivo:	Diesel
Najeto:	0 km

R-CODE

paměť závad nečtena
nelze se spojit / asi chyba auta

během jízdy
[P-1650]
[P-1651]

trvalá závada
sporadická závada

Doposud provedeno bez úspěchu

Injection pump (overhauled by Bosch service)
Glow plugs
Overhaul of cylinder head

Závěr

VOZIDLO JSEM NEOPRAVOVAL

Repaired: The problem of the workshop is that they are using test equipment of insufficient quality. After reading the DTC memory and using the appropriate oscilloscope, the fault was immediately revealed. The engine noise fault, around 3000 rpm is connected with the bad starting.

The actual cause of all these problems was a damaged ground ring connector on the transmission.

Obrázky, fotografie a soubory

Pic. 1: Can Bus I (1480/1)

Pic. 2: FCD - wiring diagram for alternate testing of pump CAN (1480/2)

It is necessary to determine if the noise is from the ECU or not. After disconnecting the connector from the ECU and the 120 Ohm resistor we measured pins 99 and 100, also pins 1 and 2 with a 2 channel oscilloscope.

Pic. 3: At ECU (1480/3)

Pic. 4: At fuel pump control unit (1480/4)

Pic. 5: Can - unsuccessful start (1480/6)

Channel 1 - Can Low (RED)
Channel 2 - Can High (BLUE). The signal is badly distorted during start.

Pic. 6: Can x ECU feed - before start (1480/7)

Channel 1 - Can Low

Channel 2 - ECU power feed

Recessive voltage reaches 2,5V.
Both signals are without fault.

Pic. 7> Can x ECU feed - unsuccessful start (1480/8)

Channel 1 - Can Low

Channel 2 - ECU power feed

Constant changes of recessive voltage are not connected with power feed of the ECU.

Pic. 8: Can x ECU ground - unsuccessful start (1480/9)

Channel 1 - Can Low (RED)

Channel 2 - ECU ground pin 1 (BLUE)

During start the ECU ground potential copies Can Low. The cause could be the ground....

Pic. 9: Can x ECU ground - continued start (1480/10)

Channel 1 - Can Low (RED)

Channel 2 - ECU ground pin 1 (BLUE)

During cranking the ECU ground potential copies Can Low!

Pic. 10: Ground test - start (1480/11)

Increased voltage during cranking on the ECU, fuel pump control unit and engine grounds! This increased potencial has direct influence on recessive voltage of the CAN Bus data line.

Pic. 11: Testing grounds - continued start (1480/12)

After introducing a new extra ground connection to the engine, we measured lower voltage on the engine ground, but there was no change to voltage on the grounds of both the control units. We can see the main cause of the CAN signal distortion on the waveform and the reason why a DTC was stored in the ECU memory after an unsuccessful start. After adding new grounds to both the control units, the engine started at first instance, no problem.