Motronic M 1.5 Checking Procedures Opel Frontera A

Subject: Motronic M 1.5 Checking Procedures

Vehicles: All with Motronic M 1.5

This Technical Information Bulletin contains important information about and modifications to the Motronic M 1.5 in Model Year 1991, which are not contained in the "System Checking with TECH 1, Program Module Opel/Vauxhall 90/91 ECU" brochure or the "Motronic M 1.5, Program Module Opel/Vauxhall 89/90 ECU" brochure.

This Technical Information Bulletin should be filed along with the "Motronic M 1.5 Program Module Opel/Vauxhall 89/90 ECU" Checking Procedures brochure.

Time Allowance: The modifications carried out do not affect the published time allowances.

Survey of the Vehicles to be Checked

(Checking Procedures "Motronic M 1.5" - page 5)

2.5 Manometer KM-J-34730-1 (only C 24 NE, C 26 NE*, C 30 SE, C 30 SEJ) or MKM-588

For measurement of the fuel pressure, two different manometers are used.

· Manometer KM-J-34730-1 for C 24 NE, C 26 NE*, C 30 SE and C 30 SEJ

· Manometer MKM-588 for C 16 SEI, C 20 NE, 20 NE, 20 SEH, 20 SER, C 20 NEF, C 20 NEJ and C 30 NE

Peculiarities when using KM-J-34730-1:

The manometer is used for checking the fuel pressure in the injection system. It is connected via a special threaded connection to a valve on the intake manifold.

Note: Depressurize the system before connecting and installing.

After connection, the hose between the intake manifold and the gauge must be bled to avoid incorrect measurements. A bleeding hose with a hand valve is integrated into the gauge.

* For measuring fuel pressure on the C 26 NE engine, use Manometer KM-J-34730-1 in conjunction with Adapter KM-J- 34123.

(Checking Procedures "Motronic M 1.5" - page 11)

DATA LIST

Note:

The air/fuel mixture correction of the oxygen sensor regulation can be evaluated with the O2 INTEGRATOR If, for example, the air/fuel mixture is too lean, the value of the O2 INTEGRATOR and thus the injection period are increased in steps until the oxygen sensor signals a mixture that is too rich. After this, the O2 INTEGRATOR is decreased again in steps and thus the injection period reduced until the oxygen sensor indicates a mixture that is too lean (only with closed loop).

O2 INTEGRATOR 128 means either: stochiometric air/fuel ratio approx. 14.7 parts by weight air to one part by weight fuel, i.e. during combustion, one air particle is available for each fuel particle.

or: The loop has been opened by the control unit, because there is a malfunction (e.g oxygen sensor defective) or the conditions for closed loop are not yet fulfilled.

or: The system functions according to the EC norm (open loop system).

O2 INTEGRATOR < 128 means: System gets leaner, mixture too rich (injection period is decreased).

O2 INTEGRATOR > 128 means: System gets richer, mixture too lean (injection period is increased).

(Test step no. 30 - Checking Procedures "Motronic M 1.5" - pages 84 - 90)

Note: Note:

The O2 INTEGRATOR affects the injection period and thus the amount of fuel that is injected. As the fuel quantity depends on the fuel pressure, an incorrect fuel pressure is noticeable in the following ways:

· Fuel pressure too high: O2 INTERGRATOR and thus injection period are decreased in steps (system gets leaner).

· Fuel pressure too low: O2 INTEGRATOR and thus injection period are increased in steps (system gets richer).

In order to be able to evaluate a deviation in the O2 INTEGRATOR value, the O2 BLM IDLE THR. correction and O2 BLM PART THR. correction must also be evaluated.

Possible correlations when nominal values are not attained:

· O2 INTEGRATOR < 108 and O2 BLM IDLE THR. < 68: System gets leaner, mixture too rich.

· O2 INTEGRATOR < 108 and O2 BLM PART THR. < 112: System gets leaner, mixture too rich.

· O2 INTEGRATOR > 148 and O2 BLM IDLE THR. > 188: System gets richer, mixture too lean.

· O2 INTEGRATOR > 148 and O2 BLM PART THR. > 144: System gets richer, mixture too lean.

DATA LIST

Trouble-shooting: Nominal Value: Cause of Fault:

C 16 SEI, C 20 NE, 20 NE, 20 SEH, 20 SER,

C 20 NEF, C 20 NEJ and C 30 NE:

Measured value < 108 steps (system gets

leaner, mixture too rich)

· Check fuel pump pressure Feed pressure: · Fuel pressure

(observe safety regulations) C 16 SEI, C 20 NE/NEF/NEJ,

20 NE and 20 SE/SEH/SER:

1.8 to 2.2 bar/26.1 · Pressure regulator defective

to 31.9 psi C 30 NE :

2.3 to 2.7 bar/

33.35 to 39.15 psi · Return line blocked or kinked

In addition

- Install manometer in feed and Return pressure:

return Engine running at idle

speed C 16 SEI, C 20 NE/NEF/NEJ,

20 NE and 20 SE/SEH/SER :

0.3 to 1.5 bar/ · Splash baffle in fuel tank

4.35 to 21.75 psi C 30 NE : blocked

0.3 to 1.5 bar/4.35 to 21.75 psi

· Remove vacuum hose

from fuel pressure Feed pressure: · Vacuum hose to fuel

regulator. C 16 SEI, C 20 NE/NEF/ leaky pressure regulator

NEJ, 20 NE

Close off hose and 20 SE/SEH/SER :

2.5 to 3.0 bar/36.25 to 43.5

psi C 30 NE :

3.0 to 3.5 bar/43.5 to 50.75 psi

Measure pressure in system Return pressure:

as above

DATA LIST

Trouble-shooting: Nominal Value: Cause of Fault:

C 16 SEI, C 20 NE, 20 NE, 20 SEH, 20 SER,

C 20 NEF, C 20 NEJ and C 30 NE: Further Causes of Fault:

· Tank vent valve constantly open

· Leaky injection valves

· Temperature sensor defective

(s. test step 06)

· Oxygen sensor defective

(see test step 29)

· Idle CO potentiometer maladjusted (open loop systems only)

· Control unit defective

DATA LIST

Trouble-shooting: Nominal Value: Cause of Fault:

C 16 SEI, C 20 NE, 20 NE, 20 SEH, 20 SER,

C 20 NEF, C 20 NEJ and C 30 NE:

Measured value > 148 steps (system gets richer,

mixture too lean)

· Check fuel pump pressure Feed pressure: · Fuel pressure too

(observe safety regulations) C 16 SEI, C 20 NE/NEF/

NEJ, 20 NE and

20 SE/SEH/SER : 1.8 to 2.2

bar/26.1 · Fuel pump defective

to 31.9 psi C 30 NE :

2.3 to 2.7 bar/

33.35 to 39.15 psi · Splash baffle in tank loose

In addition

- Install manometer in feed and Return pressure: · Fuel filter dirty

Engine running at idle speed 20 SE/SEH/SER :

0.3 to 1.5 bar/4.35 to

21.75 psi C 30 NE :

0.3 to 1.5 bar/4.35 · Dirty pre-filter

to 21.75 psi

· Check pump fuel feed quantity (see Technical Data)

· Remove vacuum hose from

fuel pressure Feed pressure:

regulator. C 16 SEI, C 20 NE/NEF/NEJ, 20 NE and

Close off hose 20 SE/SEH/SER : 2.5 to 3.0 bar/36.25 to

43.5 psi C 30 NE : 3.0 to 3.5 bar/43.5

to 50.75 psi

Return pressure:

as above

DATA LIST

Trouble-shooting: Nominal Value: Cause of Fault:

C 16 SEI, C 20 NE, 20 NE, 20 SEH, 20 SER,

C 20 NEF, C 20 NEJ and C 30 NE: Further Causes of Fault:

· Injection valve defective or dirty

· Poor fuel quality

· Intake system leaky (air loss)

· Temperature sensor defective

(see test step 06)

· Oxygen sensor defective

(see test step 29)

· Idle CO potentiometer maladjusted (open loop systems only)

· Exhaust system leaky

· Control defective

Table 2 - Trouble Code Table

(Checking Procedures "Motronic M 1.5" - page 106)