comprobacion rendimiento y consumo de combustible

7/23/2019 Comprobacion Rendimiento y Consumo de Combustible

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© Scania CV AB 2009, Sweden

00:03-13Issue 4 en

Checking performance and fuelconsumption

PGRT and FKN series

Work description



2 © Scania CV AB 2009, Sweden 00:03-13

Contents

Introduction ..................................................................................3

Procedure ..................................................................................5

Preparations ..................................................................................6

Asking the customer ..................................................................................7Analysing tacho charts .............................................8

Checking how the vehicle is drivenand the pulling power ................................................................................10

SCOP...................................................................... 11Stored operational data ...........................................15Acceleration test on a flat road...............................26Hill test ................................................................... 28

Troubleshoot the vehicle ................................................................................31High fuel consumption ...........................................31Low power output or poor pulling power............... 32Abnormal smoke emission .....................................32Troubleshooting the vehicle, trailer and

powertrain...............................................................34Troubleshooting the fuel and fuel system ..............35Troubleshooting the electronic control system.......36Troubleshooting the charge air system...................37Troubleshooting the EGR system...........................38Troubleshooting the exhaust system ...................... 39

Contents



00:03-13 © Scania CV AB 2009, Sweden 3

Checking performance

Introduction

High fuel consumption and poor pulling power are not alwayscaused by a technical fault in the vehicle. The fuel consumptionand pulling power are greatly influenced by the following factorsfor example.

• How the driver operates the vehicle

• The total weight of the vehicle

• Use of the power take-off

• The energy content of the fuel

• The air resistance of the vehicle

• The rolling resistance of the vehicle

• The road surface

• The topography

• The weather conditions

The following describes a timesaving and efficient procedure to

check performance and fuel consumption.

Introduction




Introduction




Procedure

A technical investigation of the vehicle is bothexpensive and time consuming. Therefore, firstensure that the problem is not caused by any of

the factors on the preceding page.

This is achieved by following steps 1-3 below. Note that the actions described in the first threesteps are not exact methods of measurement.You will however gain an indication ofwhether the fault is due to the vehicle or due toother circumstances.

IMPORTANT! Allow the customer to be present when you carry out step 3 so that the

customer understands what your conclusion isand how you reached it.

Allow the vehicle to remain outside theworkshop until you are ready to carry outstep 4.

1 Preparations

Note down any fault codes.

Save and print the vehicle’s stored

operational data using SDP3.

If high fuel consumption is the problem -request information from the tachographand driver’s log-book in order to carry outa correct performance check. The longerthe time period being reviewed, the greaterthe accuracy.

2 Asking the customer

Find out everything that the customer

knows about the problem.

3 Checking how the vehicle is driven andthe pulling power

Analyse the vehicle in SCOP.

You can prepare yourself before meetingthe customer by accessing the vehiclespecification in SCANIA MULTI and thenentering this information into SCOP. Youmust however check that this information

corresponds to the vehicle.

Procedure

Analyse the stored operational data thatyou obtained. Compare this with theinformation obtained from SCOP.

If the customer claims that the vehicleseems to have poor pulling power, this can

be checked by carrying out a performancetest. You can carry out an acceleration testor a hill test.

4 Troubleshoot the vehicle

If the above analysis indicates that the faultis with the vehicle - troubleshoot thevehicle.

The above steps are described in more detail inthis booklet.




Preparations

There are many things that can be investigated before beginning to troubleshoot the vehicle.Therefore, allow the vehicle to remain outsidethe workshop.

At this point you should only carry out thesteps below.

• Note down any fault codes stored in thevehicle.

• Obtain the vehicle’s stored operationaldata.

• If high fuel consumption is the problem,the following points should also be carried

out.

• Request to see a driver’s log-book thatdescribes the fuel consumption.

• Request information from thetachograph for different drivingsituations.

• Measure the fuel density by weighing

1 litre (= 1 dm3 ) of the vehicle’s fuel oruse measuring equipment 588 158. InSCOP, density is indicated using the

unit kg/m3.

Lower density results in lower engine power output. The power output of ourengines is stated for a fuel density of

840 kg/m3 at 15°C.

Preparations




Asking the customer

Note: Before carrying out the following stepsyou should first follow the instructions in thesection Preparations.

Find out as much as you can about how thecustomer experiences the problem, by goingthrough the following list together.

Find somewhere quiet and undisturbed to sitdown with the customer.

Use the information to build up a picture of the problem and the troubleshooting to follow.

• What is the problem? High fuelconsumption? Poor pulling power?

• Is the problem based on a comparison withanother vehicle? If so, are the conditions thesame for both vehicles? For example,compare the rear axle gear ratio, engine

power output and total weight of bothvehicles.

• Has the problem always been present or didit arise at a certain time?

If the problem arose at a certain time, itcould be due to a technical fault orsomething else being changed at that time.

Analyse any fault codes that were retrievedand see if they can indicate what the causeof the problem could be. Note down yourconclusions and save them for anytroubleshooting of the vehicle that may berequired.

• How is the vehicle maintained?

Could poor maintenance be the cause of the problem?

• Have they changed the trailer to checkwhether the problem is related to that?

• Have they checked by having the vehicledriven by different drivers?

• If high fuel consumption is the problem, thefollowing points should also be carried out.

• Select information from the tachographthat represents how the vehicle is used.If the vehicle has a tachograph withgraph charts - analyse the tacho chartsaccording to the section Analysing tachocharts. If the vehicle has a digitaltachograph - print the information fromthe tachograph.

• Using the driver’s log-book, find out thefuel consumption for the same dayscovered by the tachograph.

Enter the following data - obtained usingthe tachograph - into SCOP.

• The cruising speed. The speed the driverattempts to maintain for most of the

journey.

• The number of stops (include thosetimes when the vehicle has had a speed

below 20 km/h).

• Road distance.

• The average speed. Calculate theaverage speed by dividing the drivendistance by the time it took to cover thatdistance. Disregard longer stops such as

rest stops.

Asking the customer




Analysing tacho charts

Asking the customer

Interpret the tacho chart as follows.

A tacho chart.

1 Time scale in hours

2 Vehicle speed

3 One stop

4 Road distance. The distance between each peak on the curve indicates that the vehicle hastravelled 10 km.




Asking the customer




Checking how the vehicle is driven and the pulling power

Note: Before carrying out the following stepsyou should first follow the instructions in thesections Preparations and Asking the customer.

IMPORTANT! Let the customer be presentwhen you follow this section so that thecustomer understands what your conclusionsare and how you reached them.

This section describes how to check if thevehicle actually consumes too much fuel or has

poor pulling power.

The section is subdivided as follows.

• SCOP - the information which should beentered into the SCOP program isdescribed here.

In SCOP there are features such as powerand torque diagrams, information foracceleration and hill tests, plus anindication of how much fuel the vehicleshould consume and the most economicalroad speed range and engine speed rangefor the vehicle.

• Stored operational data - explains how toanalyse the stored data you obtained.

• Acceleration test - explains how to checkthe pulling power of the vehicle bycarrying out an acceleration test.

• Hill test - explains how to check the pulling power of the vehicle by carryingout a hill test.





SCOP

In the SCOP program you can specify thevehicle and obtain the information below.

• Power and torque diagrams - the power

and torque curves indicate, among otherthings, within which engine speed rangethe engine achieves maximum torque andthe engine speed at which torque

breakaway begins. If the vehicle is drivenat an engine speed where breakaway hasstarted the engine will have poor pulling

power.

The stored operational data of the vehicleshows the the engine speed ranges in which

the vehicle was driven. Compare with theSCOP power and torque diagram.

• Data from an acceleration test on a flatroad

• Data from a hill test

• Fuel consumption - compare the SCOPvalue with the fuel consumption youcalculated using the figures from thedriver’s log-book. Compare with thecalculated value obtained from the storedoperational data.

IMPORTANT! The fuel consumption fromSCOP only gives an indication of what the fuelconsumption should be. It should not beregarded as a precise fuel consumption value.

• The most economical vehicle speedrange - compare with the cruising speedshown by the tachograph. Also compare

with the vehicle speed shown in the storedoperational data.

• Recommended engine speed intervals -compare with the engine speeds at whichthe vehicle has been driven according tothe stored operational data.

The following is a short description of theinformation to be entered into SCOP. TheSCOP user manual gives a more detaileddescription of how to use the program.





General information for SCOP

Below is a description of which informationmust be entered, irrespective of whether the

problem concerns high fuel consumption or poor pulling power.

Enter information about:

• Engine type

You do not need to choose an exhaust brake.

Allow the Power output factor to remainas 1.

• Gearbox and whether the customer uses theretarder, if fitted.

• Rear axle gear and gear ratio.

• Tyres.

• Fuel temperature and density.

Note: The fuel density and temperature areimportant for the result obtained, and it istherefore necessary that this information isentered.

• Air temperature.

If an acceleration test or a hill test is to be performed, enter the current airtemperature.

To check fuel consumption indicate theaverage temperature for the days to beanalysed.

• Gross train weight of the vehicle.

• Weight on the driving axle.

• Frontal area information.

• Information about the road surface.

If poor pulling power is the problem, youonly need to select the type of road surface.

If high fuel consumption is the problem,you should also select the type oftopography.

• Click on the calculator.

The following pages describe how to proceed,depending on whether the pulling power is

poor or whether the fuel consumption is high.





Information in SCOP when thepulling power is poor

It is not necessary to enter more informationinto SCOP if you only want to check the

pulling power.

You can obtain the following information.

1 Engine power and torque diagram.

The torque curve indicates, among otherthings, within which engine speed rangethe engine achieves maximum torque andthe engine speed at which torque

breakaway begins. If the vehicle is drivenat an engine speed where breakaway isactivated, the engine will have poor pulling

power.

The vehicle’s stored operational data can be used to check in which engine speedranges the vehicle has been driven.Compare with the power and torquediagram.

2 Data from an acceleration test on a flatroad and hill test.

The information in the group box Acc.

should be used when you carry out anacceleration test.

The information in the group box Hill testshould be used when you carry out a hilltest. There you must also enter the gradientof the hill. In the section Hill test is anexplanation of how to measure thegradient.

Enter the data in the group boxes and thenfollow the instructions in the sections

Acceleration test and Hill test.





Information for SCOP when thefuel consumption is high

If high fuel consumption is the problem youshould continue to enter the information intoSCOP as described below.

Note: First you must enter the information asdescribed in the section General informationfor SCOP.

Enter the following information:

1 Whether the vehicle has been subjected to power driving, i.e. outside the green enginespeed range. Check this by looking at thevehicle’s stored operational data.

2 Whether the power take-off has been used

on the vehicle.

Select power take-off and then enterinformation about the power output, powertake-off speed and operating time.

3 A stretch of road which corresponds withinformation from the tachograph.

4 The number of stops according to thetachograph.

5 The cruising speed according to the

tachograph.When you have entered all the information.

1 Click on the calculator.

2 Compare the average vehicle speed youcalculated using the information from thetachograph with the average speed thatSCOP has calculated. The speeds shouldcorrespond.

3 You can now see the fuel consumptionfigure that SCOP has calculated.

There are many factors affecting fuelconsumption. It is important that all data inSCOP is entered as correctly as possible sothat the calculated fuel consumptioncorresponds. This gives an indication ofhow much fuel the vehicle shouldconsume.

If the actual fuel consumption of thevehicle is lower than or equal to thecalculated consumption, there is no

problem with the fuel consumption.If the actual fuel consumption of thevehicle is higher than the calculatedconsumption - continue according to thesection Stored operational data.





Stored operational data

According to the section Preparations youshould have obtained the vehicle’s storedoperational data. It is now time to analyse thisdata.

The engine control unit is one of the controlunits which stores operational data. Whenvehicle information is stored using SDP3 theoperational data can be read off from the controlunit’s total running time.

If the operational data from a vehicle has beenstored on several occasions the two files can becompared, providing operational data for a

particular period.

This section describes the operational data thatis useful when analysing vehicle performanceand fuel consumption.

Go through the operational data of the vehiclewith the customer and compare it with theresults you obtained from SCOP.





Speed

The bar chart shows an example of operationaldata for vehicle speed. In the bar chart it is

possible to see for what part of the operationaltime the vehicle has been driven within thedifferent speed ranges.

Compare the vehicle speed with the mosteconomical vehicle speed range that youobtained using SCOP.

At cruising speed the engine speed should bewithin the green engine speed range.

If the bar chart indicates that the vehicle has

been driven a lot at low speed, but this is not thecase, there may be an error in the message fromthe tachograph to the engine control unitregarding the vehicle speed. If the vehicle speedsignal is incorrect the engine control unitregisters a preset speed value of 15 km/h.





Coolant temperature

The bar chart shows an example of operationaldata for engine coolant temperature. In the bar

chart it is possible to see for what part of theoperational time the engine coolant temperaturehas been within different ranges.

A cold engine consumes more fuel than a warmengine.

On certain engines, the engine power output isreduced slightly at coolant temperaturesexceeding 100°C.





Engine speed

The bar chart shows an example of operationaldata for engine speed. In the bar chart it is

possible to see for what part of the operationaltime the engine speed has been within differentranges.

The engine speed ranges differ betweendifferent control units.

When the vehicle is driven at engine speedswithin the green zone on the tachometer thevehicle consumes the least fuel.





Charge air temperature

The bar chart shows an example of operationaldata for charge air temperature. In the bar chartit is possible to see for what part of theoperational time the vehicle has been drivenwithin the different charge air temperatureranges.

Under normal circumstances, the charge airtemperature should be approximately 10°Chigher than the outside temperature. If thecharge air temperature is too high, the engineoutput will be reduced and the fuel consumption

will increase.





Fuel supply pressure (HPI)

The bar chart shows an example of operationaldata for fuel supply pressure. The bars show for

what part of the operating time the supply pressure deviation has been within differentranges in comparison with the expected value.

If the supply pressure is lower than it should be,a fault code is generated and the engine torque isreduced by approximately 30%.





Load

rpm

95

0

1

43

95

1

3

0 00 0

0 00 0

0 00 0

0 00 0

0 00 0

0 00 0

0 0

0 0

0 0

0

0

0

0

0

0

2

2 1

13 6 7

5

00 0 0

0 00 0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

1

1

1

0

1

0

0

2

2

2

1

1

1 1

1

1

2

3

4

4

3

2

2

4

7

5

90

80

70

60

50

40

30

20

10

450 4 50 6 50 650 950950 1100 1250 1250 1400

1400 1550 1550 1700 1700 18501850 2000 20001100 2500 2500 1 4 2

3 6 5

Above is an example of the what the load matrixcan look like for a vehicle. The table shows forhow much of the operational time the vehicle has

been driven with a particular load in the differentengine speed ranges. The control unit only storesthe operating time when the engine speedexceeds 0 rpm.

When the vehicle is driven within the optimumengine speed range it uses the least amount fuel.

The higher the load, the higher the fuelconsumption.

Use SCOP to find out which engine speedrange(s) is(are) optimum for each engine type.Because the recommended engine speed rangesare different for each engine type, it is not

possible to draw up a general table dividingengine speeds into ranges.

Compare the stored operational data from SVAPwith the data obtained from SCOP to see if thevehicle has been driven within the recommended

ranges.





Analysing the vehicle

A high fuel consumption is often due to the factthat the vehicle has been incorrectly specifiedand it is therefore driven outside therecommended (green) engine speed ranges for a

large part of the time.

Two examples are provided below, depicting anincorrectly and correctly specified vehicle withengine DT1203.

Engine type: DT1203

Rear axle ratio: 3.08

Tyres: 295/60 R22.5

Gearbox: GRS900

When information about the vehicle is enteredin SCOP, it indicates that the vehicle has beenincorrectly specified. The speed falls in therange between the green engine speed ranges.

For those engines that have two green enginespeed ranges, when specifying a vehicle it is

possible to select which engine speed range thevehicle should fall within during normaloperation. The low engine speed range is used inorder to optimise a vehicle for low fuelconsumption. The recommended engine speedrange is used in order to obtain betterdriveability, resulting in a slightly higher fuelconsumption.

Rear axle tab in SCOP

A = Low engine speed range

B = Recommended engine speed range

1

1415

1480

1160

1240

40 50 60 70 80 90 100 km/h

3.40

3.27

3.08

2.92

2.71

A

B

1 4 7

9 7 5





When the vehicle’s stored operational data isviewed, this confirms the fact that the vehiclehas been driven outside the green engine speedranges for a large part of the operating time.

A = 20% of the operating time

B = 43% of the operating time

C = 5% of the operating time

This indicates that only 25% of the operatingtime is within the green engine speed range.

03

0 00 0

0 00 0

0 00 0

0 00 0

0 00 0

0 00 0

0 0

0 0

0 0

0

0

0

2

1

00 0 0

0 00 0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

1

1

1

1

1

2

Load

95

95

90

80

70

60

50

40

30

20

10

90

80

70

60

50

40

30

20

10 3

8

4

2

1

1

2

6 7

7

10

7

5

3

1

0

0

0

0

0

0

0

Load matrix

1 4 7

9 7 6

1

0

0

2

1

1

1

1

3

3

7

rpm

450450650

650 950950

11001250

12501400

14001550

15501700

1700 18501850 2000

20001100 2500 2500

A B C





Here the gearbox and the rear axle ratio have been modified.

Engine type: DT1203

Rear axle ratio: 2.92

Tyres: 295/60 R22.5

Gearbox: GRSO900

When information about the vehicle is enteredin SCOP, it indicates that the vehicle has beencorrectly specified. The speed falls within one ofthe green engine speed ranges.

For those engines that have two green enginespeed ranges, when specifying a vehicle it is

possible to select which engine speed range thevehicle should fall within during normaloperation. The low engine speed range is used inorder to optimise a vehicle for low fuelconsumption. The recommended engine speedrange is used in order to obtain betterdriveability, resulting in a slightly higher fuelconsumption.

Rear axle tab in SCOP

A = Low engine speed range

B = Recommended engine speed range

1400

1480

1160

1240

40 50 60 70 80 90 100 km/h

3.40

3.27

3.08

2.92

2.71

1 A

B

1 4 7 9

7 3





When the vehicle’s stored operational data isviewed, this confirms the fact that the vehiclehas been driven within the green engine speedranges for a large part of the operating time.

A = 60% of the operating time

B = 10% of the operating time

C = 10% of the operating time

This indicates that 70% of the operating time iswithin the green engine speed ranges.

0

0 00 0

0 00 0

0 00 0

0 00 0

0 00 0

00 0

0 0

0

0

0

0

0

2

1 00 0 0

0 00 0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

1

1

2

Load

95

95

90

80

70

60

50

40

30

20

10

90

80

70

60

50

40

30

20

10

3

1

1

7

1

0

0

0

0

Load matrix

0

2

1

3

1 4 7

9 7 4

5

0

1

1

0

0

4

1

1

3

5

9

13

6

11

0

0

1

1

1

1

1

2

2

2

2

1

rpm

450450650

650 950950

11001250

12501400

14001550

15501700

1700 18501850 2000

20001100 2500 2500

A B C





Acceleration test on a flatroad

Preparations

The acceleration test can be performed witheither SDP3 or SCOP.

If using SCOP, obtain the information for theacceleration test as indicated in the sectionSCOP.

The fuel density and temperature are importantfor the result obtained, and it is thereforenecessary that this information is entered.

Choose a level road with no traffic. You canuse a Clinometer (see below) to check that theroad is level.

The test requires two people - one to drive thevehicle and one to run the program.

Run the engine until it reaches normaloperating temperature before the test is carriedout.

Tools

Acceleration test using SDP3

1 Connect SDP3 to the vehicle. The test isfound under User functions in SDP3.Select Externally controlled enginefunctions from the menu and then

Regulating engine speed with accelerator pedal. The test is found under the Test tab.

2 Follow the instructions in SDP3 to carryout the test.

Clinometer Part no. 1 593 822





Acceleration test using SCOP

1 Drive the vehicle to the chosen stretch ofroad.

2 In SCOP you were given a number of gears

that the test could be performed in. Select agear which will give a time between 15 and25 seconds.

There are two engine speeds given for eachgear. You should measure the time

between these two engine speeds.

Use the stop watch in SCOP to record thetime.

3 Drive the vehicle at an engine speed of

between 800 and 900 rpm.

4 Select the previously chosen gear and fullydepress the accelerator pedal until youhave reached the highest engine speedstated in SCOP. Measure the time betweenthe two engine speeds stated in SCOP.

5 Carry out the test several times in bothdirections.

6 Calculate the average time and compare it

with the time calculated in SCOP. Adifference of 1 second is considerednormal.

If the average time is the same as the timeaccording to SCOP, this indicates that thevehicle pulling power is OK.

If the average time is longer than the timeaccording to SCOP - troubleshoot thevehicle.

If the average time is shorter than the timeaccording to SCOP, this indicates that thevehicle is more powerful than expected.





Hill test

Preparations

The hill test can be performed with either

SDP3 or SCOP.

If using SCOP, obtain the information for thehill test as indicated in the section SCOP.

The fuel density and temperature are importantfor the result obtained, and it is thereforenecessary that this information is entered.

Find an empty stretch of road. Check the slopeof the road, preferably via information from thelocal authorities, or by using a Clinometer (see

below).

The test requires two people - one to drive thevehicle and one to run the program.

Run the engine until it reaches normaloperating temperature before the test is carriedout.

Tools

Hill test using SDP3

1 Connect SDP3 to the vehicle. The test isfound under User functions in SDP3.Select Externally controlled enginefunctions from the menu and thenRegulating engine speed with accelerator

pedal. The test is found under the Test tab.

2 Follow the instructions in SDP3 to carryout the test.

Clinometer Part no. 1 593 822





Hill test using SCOP

1 Drive the vehicle to the chosen stretch ofroad.

2 In SCOP you were given a number of gears

that the test could be performed in. Choosea gear.

There is one engine speed given for eachgear. The vehicle should be able tomaintain this speed during the wholeclimb.

3 Before you reach the hill you should ensurethat the chosen gear is selected and thatyou are maintaining the engine speedstated in SCOP. The engine speed can best

be maintained by engaging cruise control.

4 Apply full throttle just before reaching thehill.

5 Maintain full throttle until you havereached the top of the hill. Observewhether the engine speed changes.

6 Carry out the test several times.

7 If the engine speed was constant then there

is no problem with the pulling power of thevehicle.

If the engine speed decreases -troubleshoot the vehicle.

If the engine speed increases then thevehicle is more powerful than expected.





Example of acceleration tests

Below are results from acceleration testscarried out with a tractor unit, with and withouta trailer. The tests were carried out with avirtually identical gross weight.

Two tests were carried out with only the tractorloaded with weights.

Two tests were carried out with the sametractor with the trailer loaded to the same grossweight.

Here it is possible to see how the rollingresistance of the trailer affects the result. Thetrailer was approximately 6 months old at thetime of the test. The tyres had no signs of beingunevenly worn. The trailer was tested, withoutremarks, on a roller brake tester to check therolling resistance.

The example shows why a tolerance of +/- 1second is necessary.

For further information see the sectionTroubleshoot the vehicle under the headingTroubleshooting the vehicle, trailer and

powertrain.

Weight(tonnes)

Gear Time (s), test 1 Time (s), test 2

18.38 6L 12.6 13.0

18.69 6L 14.3 14.5

Difference (s) 1.7 1.5





Troubleshoot the vehicle

Note: Before carrying out the following stepsyou should first follow the instructions in thesections Preparations, Asking the customer andChecking how the vehicle is driven and the

pulling power.

The following pages describe how totroubleshoot the vehicle.

Troubleshooting can be used if you have one ofthe following problems:

• High fuel consumption

• Low power output and poor pulling power

• Abnormal smoke emission

The section is subdivided into troubleshootingof the following areas:

• Vehicle, trailer and powertrain

• Fuel and the fuel system

• The electronic control system

• Charge air system

• Exhaust system

High fuel consumption

If the fuel consumption is high, you shouldtroubleshoot as described in the followingsections. Troubleshoot in the following order.

1 Vehicle, trailer and powertrain

2 Fuel and the fuel system

3 The electronic control system

4 Charge air system

5 EGR system

6 Exhaust system

The following vehicle characteristics are ofgreat importance to the fuel consumption of thevehicle.

• The vehicle specification

• The vehicle and trailer bodywork

• The optional equipment

• The wheel and axle settings

• The brakes

• The function of the entire powertrain





Low power output or poor pulling power

If the power output is low or the pulling poweris poor, you should troubleshoot as described inthe following sections. Troubleshoot in the

following order.

1 Vehicle, trailer and powertrain

2 Fuel and the fuel system

3 The electronic control system

4 Charge air system

5 Exhaust system

The quality of the fuel greatly affects the poweroutput and pulling power of the engine.Likewise, the fuel system in general also has a

great influence.

• Also check that the white smoke limiter isworking. If it is not working properly, thevehicle may seem to have poor pulling

power.

• Also check that the charge air pressuresensor and charge air temperature sensorare working. If they are not working, thevehicle may seem to have poor pulling

power.

Abnormal smoke emission

Black smoke - the relation between the amountof air and fuel supplied to the engine, and anyfaults in the exhaust system, determine theamount of black smoke produced.

1 Check the charge air system as described inthe section Checking the charge air system.

Too little air in relation to the amount offuel results in black smoke.

2 Check the exhaust system as described inthe section Checking the exhaust system.

The exhaust back pressure in the completeexhaust system and any exhaust leakage

before the last exhaust turbine (in thedirection of flow) have an effect on thesmoke emission.

3 Check the fuel and fuel system accordingto section Checking the fuel and the fuelsystem.

4 Check that the white smoke limiter isworking.

5 Check the EGR system as described in thesection Checking the EGR system.

If the EGR content at high loads is toohigh, black smoke is produced.

White smoke - white smoke is unburned fuelor water that evaporates together with the fuelin the combustion chamber.

Check the fuel and the fuel system according to

the steps below. Remedy any faults and thencheck smoke emissions right after performingthe measures.





1 Check that the white smoke limiter isworking

2 Check that the wastegate valve, iffitted, functions correctly

3 Check that the injectors are of thecorrect type and are not defective

4 Check that the cold start function, iffitted, functions correctly

5 Check that coolant is not leaking intothe combustion chamber via thecylinder liner or the cylinder head

6 Check whether there is water in thecharge air cooler

7 Check that the engine has the correctcompression by carrying out acompression test using SDP3

The compression of the engine affectsthe amount of white smoke.





Troubleshooting the vehicle, trailer and powertrain


Check the vehicle, the trailer and the

powertrain according to the steps below.Discuss with the customer those points thataccording to your conclusions may have had aneffect.

1 Use SCOP to check that the vehiclehas the correct gear ratio

Check that the vehicle has the correctratios for the gearbox and the rear axle

gear, and also for the vehicle’s transportapplication.

2 Check that the tyres are of the correcttype and dimensions and have thecorrect inflation pressure

3 Check how much the bodywork affects

the air resistance of the vehicle

The bodywork affects the fuelconsumption. Check the appearance ofthe bodywork.

Factors such as different heights oftractor and trailer and long distance

between vehicle and trailer have aneffect.

Using different trailers or bodyworkfrom time to time may also have an

effect.Loose tarpaulins may also have thiseffect.

4 Check to see if there is any extraequipment that affects the airresistance of the vehicle

A vertical roof sign on the vehicle, bull bars and decoration such as the Michelin

man all affect fuel consumption.

5 Check that none of the brakes in the

vehicle combination are binding

6 Check that the vehicle and the trailerhave the correct wheel and axlesettings

If the wheel and axle settings areincorrect, the rolling resistance of thevehicle will be greater, leading toincreased fuel consumption.

7 Check that there is no abnormalfriction in components such as wheelbearings or the bearings in thepowertrain

8 Check if there is any extra equipmentfitted that affects the fuel

consumption, for example, powertake-off and AC cooling fans




Troubleshooting the fuel and fuel system

Check the fuel and the fuel system according to

the steps below.Repair the fault and immediately afterwardscheck fuel consumption, power output, pulling

power or smoke emissions, depending on thesubject of troubleshooting.

1 Check with SDP3 to see if the enginecontrol unit has generated any faultcodes

2 Check that the fuel is of an approvedquality

The quality of the fuel greatly affects thefuel consumption. The fuel consumptionmay be normal in relation to the qualityof the fuel. See the service information inScania Multi.

3 Check that the fuel supply pressure iscorrect

Check the supply pressure with SDP3 ormeasure it according to the instructionsin the service information in ScaniaMulti. If the supply pressure is too lowthe engine will lose pulling power. Thiscan in turn lead to the driver changingdown, leading to power driving andincreased fuel consumption.

The following factors may affect thesupply pressure:

- The suction strainer in the tank is blocked.

- The fuel line between the tank and thefeed pump is leaking or constricted. Aleak can be difficult to detect.

- The feed pump is not workingsatisfactorily.

- The fuel filter is blocked.

- The overflow valve is faulty.


4 Check that there are no fuel leaks

5 Carry out a performance test usingSCOP

6 Carry out a compression test andcheck cylinder balancing using SDP3

7 Troubleshoot the unit injectors andfuel system

PDE: Troubleshoot and overhaul theunit injectors according to the sectionin Scania Multi that covers unitinjectors, PDE, Checking and cleaning

HPI: Troubleshoot according to thesection in Scania Multi that coverstroubleshooting of the Scania HPI fuelsystem





Troubleshooting the electronic control system

Check the electronic control system according

to the steps below.

Repair the fault and immediately afterwardscheck fuel consumption, power output, pulling


1 Check the earthing point for thecontrol unit

It is important for the control unit to beearthed correctly.

2 Ensure that control unit connectorsare clean and not coated with verdigrisor oxides





Troubleshooting the charge air system

Check the charge air system according to thesteps below.



1 If the vehicle has a winter air intake,check that it is correctly adjusted

Important! The winter position shouldonly be used when the outdoortemperature is below +5°C.

2 Check that the intake system is of theoriginal design and that the air filter isnot blocked

Check the vacuum in the intake (vacuumindicator, refer to maintenanceinstructions step 1) which will indicatewhether there is a fault.

3 Check the intake manifolds before theair filter and between the air filter andturbocharger

Check that none of the bellows have beensqueezed together.

4 Check that all the intake manifolds areintact and that the intake system is notleaking

Pressure test the charge air cooleraccording to the description in theservice information in Scania Multi.

4b Check the charge air pressure sensor

Measure the charge air pressure usingmeasuring kit 99 362 (see description in

Scania Multi) and compare it to thecharge air pressure in SDP3.

Note: Remember that SDP3 displaysabsolute pressure (turbocharger pressure

plus atmospheric pressure), i.e. it should be approximately 1 bar higher than the pressure measured.

5 Check that the turbocharger isworking and is free from oil and sootdeposits

6 Check that the charge air cooler is notblocked, internally or externally

The temperature after the charge aircooler should be 5-10°C above ambienttemperature.

7 Check that the damper in the EGRvalve is not jammed and that theventuri is working correctly

8 Check that the wastegate valve, iffitted, functions correctly

9 Check that the noise baffle, if fitted,functions correctly





Troubleshooting the EGR system

Check the EGR system according to the steps below.



1 Visually check that the exhaust brakeis not applied

2 Check the charge air temperaturesensor and mass flow sensor usingSDP3

3 Check whether the water-cooled EGRcooler is blocked

The water-cooled EGR cooler may be blocked if the engine had a serious fault,

such as a leaking injector.Clean the EGR cooler. Refer toWorkshop Manual, subgroup 01-65EGR system, water-cooled EGR cooler.

4 Make sure there are no leaks in thecharge air system

Leakage in the charge air system cancause black smoke.



Troubleshooting the exhaust system

Check the exhaust system according to thesteps below.

Repair any faults, and immediately afterwardscheck fuel consumption, power output, pulling

power or smoke emissions, depending on whatyou are troubleshooting.

1 Check that the exhaust system is of theoriginal design and that the silencer isintact.

The exhaust back pressure must not betoo high.

2 Check that there are no leaks in theexhaust system before the gas flowreaches the last exhaust turbine.

3 Check that the exhaust brake is correctly

adjusted, is not worn and is workingsatisfactorily. Also check the

proportional valve.

4 Check that the turbine in theturbocharger is working and not chafingon the turbine housing.

5 Also check the power turbine in theturbocompound unit (engines equippedwith turbocompound).


comprobacion rendimiento y consumo de combustible

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