DAF LF45, LF55 Series. Manual - part 157

©

 200505

1-3

Tractive problems

DIAGNOSTICS

ΛΦ45/55 series

2

1

Result of first acceleration test
If the acceleration time is not achieved, first carry 

out the following work.

-

Check the fuel system for the presence of air.

-

Replace or clean the air filter element.

-

Check the adjustment of the wastegate on 

the turbocharger.

-

Check the exhaust brake butterfly valve for 

correct operation.

-

Check the charge cooler exterior for dirt 

deposits.

-

Clean the water separator.

-

Check that the primer pump is attached.

-

Replace the fuel fine filter.

-

Check the suction pipe of the tank for 

clogging by coarse dirt.

-

Check the fuel suction line for clogging and 

flow resistance.

-

Check the fuel tank for fouling. Clean with a 

steam cleaner, if necessary.

-

Check the air intake system for any leaks.

-

Check the exhaust system for any leaks.

-

Check the exhaust system for blockages by 

measuring the exhaust gas back pressure.

-

Check the turbocharger impellers on the 

compressor and turbine sides for damage 

and for deposits of salt or any other 

contaminants.

-

Check both the valve clearance and the DEB 

clearance.

-

Check the injector pipes for damage.

-

Check the fuel gallery/rail pressure.

-

Check the fuel lift pump output.

-

Check whether the right type of components 

has been fitted. This includes turbocharger, 

injectors, etc.

-

Check the opening pressure of the injectors.

Repeat the acceleration test. If necessary, plot a 

boost pressure curve.

DIAGNOSTICS

1-4

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 200505

Tractive problems

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ΛΦ45/55 series

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1.3 ACCELERATION TEST FORM

General data

Customer's name:

Chassis number:

Registration number:

Test conditions

Weather conditions: dry / rain / wet road / drizzle

Wind force: none / average / strong 

Outside temperature:

 °C

Vehicle data

Vehicle type:

Trailer type:

Superstructure:

Total combination weight:

 kg

Total vehicle height:

 m

Cab type: day / sleeper / space / superspace

Aerodynamics: roof spoiler / fenders / front spoiler / skirts / sun visor /

Engine type:

Gearbox type:

Transmission:

Rear axle type:

Transmission:

Tyre size: front:

rear:

Tyre make:

Energy:

Space between cab and superstructure/trailer:  

 m

TOPEC data

Starting speed:

 km/h

End speed:

 km/h

Gear selection:

Acceleration time:

 

 sec.

Measured time of 

outward journey:

1:

 sec.

2:

 sec.

Average time of outward journey:

 sec.

3:

 sec.

Average time: 

 sec.

Measured time of 

return journey:

1:

 sec.

2:

 sec.

Average return time:

 sec.

3:

 sec.

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 200505

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Tractive problems

DIAGNOSTICS

ΛΦ45/55 series

2

1

1.4 ACCELERATION TEST USING DAVIE

The acceleration test can also be carried out 

using DAVIE. Collect the necessary data and, 

after starting DAVIE, go to the engine 

management system and carefully follow the 

instructions in DAVIE for carrying out the test 

correctly.

The test results should be saved to diskette after 

each test.

The acceleration test in DAVIE 

should only be started when the 

vehicle is stationary. As the 

communication between the 

accelerator pedal sensor and the 

unit will be broken for a short time 

when DAVIE is started up, this can 

lead to dangerous situations when 

the vehicle is being driven.

When driving, never start a "direct test" or "guide 

diagnosis".

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DIAGNOSTICS

1-6

©

 200505

Tractive problems

1

ΛΦ45/55 series

2