DAF CF65, CF75, CF85 Series . Manual - part 14

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System inspection with DAVIE XD

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DAVIE XD diagnostics manual 

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3. SYSTEM INSPECTION WITH DAVIE XD

3.1 GENERAL

If the vehicle has been modified and the 

configuration changed, the electronic unit may 

have to be re-programmed.

If the electronic unit is replaced, new UPEC 

software must be loaded into the unit using 

DAVIE.

The immobiliser code for the fuel release is 

automatically "read" when the ignition is switched 

on.

UPEC

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System inspection with DAVIE XD

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DAVIE XD diagnostics manual

3.2 ENGINE BRAKE TEST

Note:

1.

This test must be done with the engine at 

operating temperature.

2.

To obtain a good comparison, ensure that 

during the test neither the air-conditioning 

system compressor nor the air supply 

system are switched on or off.

During this test, the engine speed will be 

increased and decreased while the exhaust 

brake/DEB is activated.

After this, the engine speed will again be 

increased and decreased, this time without the 

exhaust brake/DEB being activated.

In both cases the fall in engine speed when 

slowing down will be measured per second.

The ratio between the measured values with and 

without activated exhaust brake/DEB will be 

expressed as a percentage.

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System inspection with DAVIE XD

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DAVIE XD diagnostics manual 

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3.3 SPEED VARIATION CONTROL TEST

One of the controls of the engine management 

system is the uniform operation of the engine via 

the speed variation control (this speed variation is 

recorded via the crankshaft sensor).

Too large a variation in speed is prevented by 

correcting the quantity of injected fuel per 

cylinder.

Due to a fault in the fuel system (bad injector, fuel 

leakage etc.) the fuel correction applied to a 

cylinder may have increased to such an extent 

that it falls outside the permitted specification.

Note:

Bear in mind the fact that a mechanical defect in 

a cylinder (compression loss) may affect the fuel 

correction for another cylinder that falls outside 

the permitted specification.

Here the relation is as follows:

In the "speed variation control" test the fuel 

correction of each cylinder is determined during a 

trip cycle (a trip cycle where a high engine load is 

required for a long period), on the basis of the 

total fuel consumption.

The "speed variation control test" in DAVIE is one 

of the diagnostic tools that can be applied in case 

of complaints about fuel consumption and 

reduced engine power.

Other tests are the acceleration test and plotting 

a boost pressure curve; in principle these have to 

be carried out before the "speed variation control 

test" is carried out.

in case of compression loss of cylinder:

1

5

3

6

2

4

a positive fuel correction on cylinder:

3

6

2

4

1

5

UPEC

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System inspection with DAVIE XD

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DAVIE XD diagnostics manual