Vauxhall Workshop Service and Repair Manuals

Subject:

 

Customer Complaints about Vehicles with 25 DT Engines regarding "Hesitations when Driving Off Hot"

 

 

Vehicles:

 

All Omega-B vehicles with 25 DT engines up to Vehicle Identification Number: 22S1195396

 

 

Condition:

 

Customers complain that the vehicles at operating temperature drive off on gradients either poorly or not at all. The problem worsens with increasing outside temperatures and payload as well as in trailer operation.

The cause is an unfavourable interplay of various factors, such as high fuel temperature, fuel quality, tolerances of the distributor fuel injection pump and calibration of the engine control unit.

Remedy:   In case of complaint, first check the affected vehicle for correct installation of the entire intake air duct system, at no charge to the customer:     1)      Inspect fabric hose in front of air cleaner housing (hose under left cover); - illus. F 6684 (I,1) -             -   for proper seating   2)      Open air cleaner housing and check air cleaner element             -   for proper seating           -   for proper condition; if necessary replace   3)      Inspect air duct insert in bumper             -   Inserts with 25DT engine must be open; if necessary install open ones; - illus. F 6684 (II,2) -

 

 

In addition, a special engine control unit and a modified fuel pump closure cap must be installed for the customer at no charge.

 

 

Replace the engine control unit according to the Service Instructions.

 

 

Removal of the fuel pump cap is performed analogously to the operation: "Fuel Supply Pump, Replase (25 DT)" of the Service Instructions, group L, as described on page L-38.

Connect the fuel lines to the new cap as shown below.

Fuel Pump Cap Connections   Cap, bottom   1     Return hose (R) 2     Connection remains free (arrow) 3     Feed hose (S)   Cap, top   4     Feed hose to distributor injection pump (S) 5     Return hose from distributor injection pump (arrow)

 

 

Important:

After performing the actions specified in the TI, visibly mark the vehicle for identification with a white dot on the top of the newly installed engine control unit.

 

 

Parts:

 

Designation			Number		Part No.		Catalogue No.
Engine control unit	MT	1		90 512 701		90 94 766
	AT	1		90 512 702		90 94 767
Cap, fuel pump			1		90 512 984		90 94 788

 

 

Time Allowance:

 

T 0378 00        Check and Repair                                                                      1.1 hrs.

                        TC: 92

 

 

+:      Check intake air guide system (inspection)

         Check air cleaner element / if necessary replace

         Replace fuel pump cap

         Remove and install Motronic / DDE control unit

         Activate immobiliser function

 

 

W 1000 00      Vehicle from Parking Place to Workplace and Back                 .2 hrs.

                        TC: 99

 

 

Note:

 

Should in individual cases the described measures not prove successful, please contact your appropriate Aftersales / Service Department or Technical Info Centre (TIC) to co-ordinate further procedures.