ISF3.8 exhaust and emission control system

The exhaust gas treatment system is designed to reduce nitrogen oxide emissions from the engine.

Measuring the exhaust system resistance

Connect a pressure gauge to the pressure take-off port in the exhaust manifold.

Install the pressure gauge at a distance of no more than one pipe diameter from the turbocharger outlet.

Allow the engine to run at minimum speed and load.

Measure the back pressure in the exhaust system.

Maximum exhaust system resistance: 40 kPa.

Diagram of the ISF3.8 exhaust and emissions reduction system — Fig. 1. Measuring the back pressure in the exhaust system.

If the pressure in the exhaust system exceeds the maximum, check it for damage.

Checking the exhaust system for damage — Fig. 2. Checking the exhaust system.

Remove the pressure gauge. Refit the plug if necessary.

Removing the pressure gauge from the exhaust manifold — Fig. 3. Removing the pressure gauge.

Removal and installation of the exhaust manifold

Disconnect the leads from the battery terminals.
Remove the turbocharger inlet and outlet pipes.
Disconnect the charge air cooler air pipes.
Remove the turbocharger (article — Removal of air intake system components).
Remove the exhaust manifold:
- untoksew the exhaust manifold mounting bolts;
- remove the spacers, the exhaust manifold and the gaskets.

Removal of the ISF3.8 exhaust manifold — Fig. 4. Removal of the exhaust manifold.

Inspection

Clean the exhaust manifold with steam. Dry it with compressed air.
Remove carbon deposits from the contact surfaces with No. 240 abrasive paper.

Cleaning carbon deposits from the exhaust manifold — Fig. 5. Cleaning the exhaust manifold.

Using a precision straight edge, check the flatness deviation of the exhaust manifold support surfaces.

Flatness check of the manifold support surfaces — Fig. 6. Flatness check of the exhaust manifold.

Place the straight edge across all the ports and measure the flatness deviation with a feeler gauge. Maximum non-flatness: 0.2 mm.

If the non-flatness exceeds the maximum, grind or replace the exhaust manifold.

Installation

Apply high-temperature anti-seize compound to the threads of the exhaust manifold mounting bolts.
Fit new gaskets, the exhaust manifold, the spacers and the locking plates, and toksew in the bolts.
Tighten the exhaust manifold mounting bolts in the sequence shown in the figure. Tightening torque: 53 N·m.

Fig. 7. Exhaust manifold bolt tightening sequence.
Install the turbocharger (article Removal of air intake system components).
Install the charge air cooler air pipes.
Install the turbocharger inlet and outlet pipes.
Connect the leads to the battery terminals.
Start the engine and check for leaks.

Exhaust gas emissions reduction system with selective catalytic reduction (toks)

Caution! After stopping the engine, wait until the toks system fluid doser has fully purged the system.

To do this, switch off the ignition and wait until the selective catalytic reduction catalyst has cooled down.

For five minutes after the ignition is switched off, the characteristic sound of the doser pump can be heard, similar to the sound of a priming pump.

toks system fluid doser

The doser draws toks fluid from the tank and delivers it to the dosing valve. All unused fluid is returned to the tank.

Diagram of the toks dosing system with selective catalytic reduction catalyst — Diagram of the selective catalytic reduction catalyst dosing system: 1 — fluid injection controller; 2 — fluid dosing module; 3 — exhaust gas outlet pipe and selective catalytic reduction catalyst; 4 — fluid dosing valve; 5 — fluid tank; 6 — fluid supply lines for exhaust gas treatment systems.

The doser operates on 12 V or 24 V.

The nominal voltage value is stamped on the doser body next to the electrical connector.

In addition, dosers are distinguished by their connector:

if the front face of the electrical connector on the harness side is grey, this doser operates on 24 V DC;
if the surface is black, the doser operates on 12 V DC.

The electrical connectors have different keyways, which prevents them from being interchanged.

External view of the toks fluid doser — Fig. 8. toks system fluid doser.

Initial check

Check the doser inlet and outlet unions for leaks (white deposit around a damaged union).

Checking the doser unions for leaks — Fig. 9. Checking the unions for leaks.

If a deposit is found, check the unions for cracks.

Fig. 10. Checking the unions for cracks.

Check the areas around the doser cover for leaks.

Removal

Caution!

The pipe connecting the doser to the valve is under low pressure and must not be disconnected while the engine is running or before the system purge is complete after the engine is stopped. Disconnecting this pipe may cause toks fluid to leak out.
Do not disconnect the batteries before the doser purge cycle is complete.
Wait at least 5 minutes after switching off the ignition before removing and/or disconnecting any components from the doser when preparing it for purging.
Do not wash the doser with water or steam. Use compressed air for cleaning.

The purge cycle is performed automatically and requires no external intervention. During the doser purge, the characteristic sound of the pump running can be heard.

Disconnect the lead from the battery negative terminal, then from the positive terminal.
Mark all toks system pipes and their connectors. If the pipes are connected incorrectly, the system will not function and the fault indicator will illuminate.
Disconnect the toks system pipes and electrical connector in the order indicated to reduce the likelihood of contaminating the electrical connector with fluid.

Diagram of the pipe connections to the toks doser — toks system fluid doser: 1 — return pipe, fluid return to the tank; 2 — inlet pipe — fluid supply to the doser; 3 — outlet pipe — fluid supply to the dosing valve; 4 — connector.

Slide the connector towards the yellow part. Once the connector starts to lift, disconnect it from the doser.
Plug the unions and the connector to prevent dirt ingress.
Untoksew the three bolts and remove the doser.

Fig. 12. Removal of the doser.

Note: the doser is dismantled only if fault symptoms appear that require it to be opened.

Untoksew the doser unions.

Fig. 13. Untoksewing the doser unions.

Make sure the O-rings are on the unions and have not become stuck inside the doser.

Cleaning and inspection

The doser is not serviceable. Do not open its body. Return the unit to an authorised Cummins service centre.

Do not immerse the module in any cleaning solution.
Do not use any detergents to wash the module.
Use a clean damp cloth to wipe the module.

Visually inspect the doser. If any cracks, damage to the body or electrical connectors are found, replace it.

If the doser filter cap is damaged, replace it.

Check the toks fluid pipe connections for damage or signs of corrosion.

An integral, non-serviceable mesh filter is fitted to the doser inlet union (1) and return union (2).

Using an air blow gun with a rubber nozzle, blow the connectors onto a sheet of white paper in the direction opposite to the fluid flow.

Check whether any dirt particles have appeared on the paper as a result of the blow-out. Dirt particles indicate a blocked connector. If the connector is blocked, it should be replaced.

Blowing out the doser connectors with compressed air — Fig. 15. Blowing out the doser connectors.

If contamination is found in the toks dosing valve inlet union, check the toks fluid tank filter.

Installation

Note: the doser unions are not interchangeable.

Fit the unions. Do not apply lubricant or sealant. Tightening torque: 4 N·m.
Before installing the doser on the vehicle, make sure it contains no contamination.
To reduce the likelihood of false toks fluid leak messages, wipe up any fluid spilled during the repair with a clean damp cloth.
Install the doser on the support bracket and secure it with three bolts. Tightening torque: 20 N·m.
Note: do not replace a 12 V doser with a 24 V module or vice versa.
Connect the electrical connector. toks fluid can cause corrosion of the electrical connector contacts.
The 12-pin electrical connector (4) is installed by sliding it into its yellow part. The connector will lower and lock onto the doser.
Connect the toks pipes in the order indicated to reduce the likelihood of accidental contamination of the electrical connector with fluid.

The toks fluid pipe connectors emit a characteristic click when they lock onto the unions.

Pull lightly on the connector to make sure it is securely locked.

Connect the leads to the battery terminals.
Make sure there are no fault codes.

Note: to check the toks fluid supply, the catalyst must be warmed up by making a journey of more than 15 minutes.

toks system fluid filter

Removal and installation

Check the area around the filter cap for leaks (white deposit around the leak point).

Checking the area around the toks filter cap — Fig. 17. Checking the fluid filter.

Disconnect the leads from the battery terminals.
Clean the doser with a clean damp cloth.
Note: do not wash the doser with water or pressurised steam.
Remove the filter cap:
- untoksew the toks fluid filter cap (1);
- remove the cap and the O-ring (2);
- pull out the toks fluid filter element (3).
Fig. 18. Removal of the filter element.

Clean the cap and make sure it is not damaged.

Install a new filter element in the reverse order of removal. Tightening torque: 20 N·m.

Connect the leads to the battery terminals.

Start the engine and check for leaks.

toks system fluid dosing valve

The toks fluid dosing valve is used to inject fluid into the exhaust gas stream before it enters the catalyst.

The dosing valve is located on the decomposition tube, which is secured to the flange with three bolts.

The dosing valve has three main connectors:

a 2-pin electrical connector that connects the dosing valve to the control unit;
a fluid supply pipe that connects the dosing valve to the doser;
a coolant supply/drain union that connects the dosing valve to the engine cooling system.

toks fluid dosing valve — Fig. 19. toks system fluid dosing valve.

Initial check

Note: toks fluid deposits may remain from previously spilled fluid or after repair.

Before replacing any components, check the system for leaks.

Check the area around the point where the fluid supply pipe connects to the dosing valve.

Check for leaks and/or white deposits at the following points:

the connection between the fluid supply pipe and the dosing valve;
the connections between the dosing valve and its body.

The formation of deposits may hide the leak point, so remove the deposits and wash the area with warm water.

Checking the dosing valve connections for leaks — Fig. 20. Checking the connections for leaks.

Removal

Disconnect the leads from the battery terminals.
Drain the coolant.
Remove dirt from the quick-release coupling and around the dosing valve body.
Remove the toks fluid hoses, then the coolant hoses, and disconnect the electrical connector from the dosing valve.

Fig. 21. Removal of the dosing valve.
Plug the unions with caps.
Remove the dosing valve gasket.
Untoksew the toksews securing the dosing valve to the decomposition tube.

Inspection

Check the condition of the dosing valve.

If leaks/deposits are found on the dosing valve connections between the valve and its body during the checks, replace the dosing valve.

If leaks/deposits are found on the fluid supply pipe connector, check the connector for cracks or signs of corrosion.

Check the electrical connector and its contacts for damage/corrosion.

Note: do not dismantle the dosing valve. This part is not serviceable.

Checking the condition of the dosing valve — Fig. 22. Checking the dosing valve.

Checking the toks fluid flow rate

Caution! Do not stand next to the container used to check the toks fluid supply, especially in a poorly ventilated room, as this may affect breathing.

The purpose of this check is to activate the fluid doser and make sure that the specified quantity of fluid solution is delivered within the specified time interval.

The check is started using the INSITE diagnostic tool. The test is performed in automatic mode.

The check is performed under the following conditions: vehicle stationary, neutral gear, key in the "ON" position.

There are 3 cycles during operation: priming, delivery and cleaning. Place the valve in a container with a volume of more than 4 l.

Cover the valve with a cloth or oilcloth to prevent splashing.

The check lasts 5 minutes. After the check, measure the quantity of fluid.

Fluid volume: 106–144 ml.

Measuring the toks fluid volume after the check — Fig. 23. Measuring the fluid volume.

If the fluid quantity does not match the nominal value:

check the toks fluid doser filling;
make sure the system lines are not blocked or restricted;
check the toks filter;
perform the check again. If the flow rate differs from the nominal value, replace the doser.

Installation

Make sure the battery is disconnected.
Install the dosing valve with a new gasket and tighten the mounting toksews. Tightening torque: 8 N·m.
Connect the quick-release couplings.
Connect the electrical connector.
Remove the caps and connect the lines.
Fill the coolant.
Connect the leads to the battery terminals.
Start the engine and check for leaks.
Check the diagnostic fault codes.

Flow rate check (detailed)

Perform a metered delivery cycle and check the following characteristics:

the shape and characteristic of the toks fluid dosing valve spray pattern;
the quantity of fluid delivered over a given time (6 minutes).

This check can be performed using the INSITE diagnostic tool during ECM module diagnostics. To perform the check, follow the instructions that appear on the display.

Note: low battery voltage may cause a reduction in the delivered fluid volume. Check the batteries before the check.

Disconnect the leads from the battery terminals.
Remove the dosing valve.
Caution! Do not apply 12 V or 24 V DC to the dosing valve, to avoid damaging it.
Connect the electrical connector and the fluid supply pipes.
Note: this check does not require the coolant circuit to be connected.

Fig. 24. Preparation for the fluid flow rate check.

Take a transparent plastic container large enough to hold the dosing valve and the measuring container (500 ml, 5 ml graduations).

Place the dosing valve in the container.

Note: the check begins with filling the dosing system. During this process, the dosing valve opens periodically to release air from the system. Some fluid may spill out, which is not a fault.

Fig. 25. Placing the dosing valve in the container.

During the check, the dosing valve atomises the fluid into very fine droplets. To prevent fine fluid droplets from evaporating and to ensure measurement accuracy, place a clean bag or lid over the valve and container.

At the start of the check, adjust the fluid spray pattern slightly. Pay attention to the following:

the appearance of excessively large droplets and fluid dripping from the nozzle;
loss of symmetry of the spray pattern (displacement to one side).

If any of these signs are found, stop the check and inspect the dosing valve nozzle. If necessary, repeat the check and adjust the fluid spray pattern. If the problem persists, replace the dosing valve.

Checking the fluid spray pattern — Fig. 26. Checking the spray pattern.

Flow rate check:

switch on the ignition;
connect the INSITE diagnostic tool;
in the ECM module diagnostic check menu, select the item related to the check with forced activation of the doser pump;
to perform the check, follow the instructions that appear on the display.

The INSITE diagnostic tool will start the check, during which fluid will be injected for 6 minutes.

At the end of the check, the INSITE diagnostic tool will automatically stop the injection. If the check needs to be stopped before it is complete, press the "STOP" button.

Measuring the injected fluid volume — Fig. 27. Measuring the fluid volume.

After the check, measure the volume of fluid injected into the container. Pour the fluid into the measuring container. Perform the check three times and average the results.

Minimum volume: 85 ml
Maximum volume: 115 ml

Note: do not pour the toks fluid back into the tank. Dispose of it in accordance with local environmental legislation.

Pouring the toks fluid into the measuring container — Fig. 28. Pouring the fluid into the measuring container.

If the fluid quantity does not meet the norm, make sure the fluid filter is not blocked. Check the pipe between the doser and the dosing valve for leaks, blockages or excessive resistance.

Note: the dosing valve may become blocked with dirt. Check the doser filter for signs of contamination and blockage before installing a new dosing valve.

Using a clean technical wipe moistened with warm water, remove the fluid layer from the equipment before disconnecting it. Install the dosing valve.

Bleeding air from the dosing system

Disconnect the toks supply line of the dosing valve.
Install an additional fluid supply line (No. 4919574).
Install a container suitable for collecting fluid at the outlet of the supply line. A 3.8 l bucket is recommended.

Fig. 29. Connecting the additional line.
Lower the end of the outlet hose from the additional line into the fluid collection container.
Switch on the ignition and connect the INSITE diagnostic tool.
In the ECU diagnostic check menu, select the item related to the manual pump mode check of the doser pump.

During this check, an attempt is made to fill the dosing system. The fluid is drained from the tank and pumped through the additional line.

Note: if the check has started, the pump will continue to deliver fluid even after an attempt to stop the check using the INSITE diagnostic tool. To stop the check, the ignition must be switched off.

During the manual pump mode check, observe the fluid flow. The appearance of bubbles indicates a leak that allows air to enter the dosing system.

If bubbles are present, check the following parts for damage or leaks: