Common Rail Performance Loss in Iveco Multicar

Hello everyone,

I have a Multicar with an Iveco engine, 2.8 liters, 106 horsepower, and common rail injection.
The vehicle is from 2006 and has 22,000 kilometers on the odometer.
Engine number 8140.43B.
Part number for HD pump: 0445020002.

The vehicle was purchased a few months ago, and since then, I've been experiencing a loss of power.
It started with a clogged fuel pre-filter and a leaking intake manifold gasket.
It had some success, but the performance is still too low. "When going uphill without a load, I achieve this with..."
The car struggles to reach 60 km/h, while a comparable vehicle easily climbs the same hill at 80 km/h. I'm having trouble maintaining 50 km/h (approximately 31 mph) on inclines, and I tend to slow down when using full throttle.

The intercooler piping is 100% leak-free and sealed.
Both fuel filters are new. Return flow measurements show that all cylinders are 95% identical. The fuel injector unit and the rail pressure sensor have been replaced.
The rail pressure is plausible, approximately 300 bar when the system is stationary, and follows the target value without significant issues.
The pre-injection pressure is 3.5 bar at the start of injection.

The engine idles roughly for about 3 minutes when cold, but then runs quite smoothly. Also, there are no black clouds of smoke when accelerating.

"There are no error messages displayed, the accelerator pedal shows 100% when fully pressed, and the boost pressure increases to approximately 0.8 bar."

Does anyone have any suggestions for a solution or a possible diagnosis?

Thank you.

What should the boost pressure be at full load?

Hello,

To the best of my knowledge, it should be between 0.8 and 0.9 bar.
There is no "target" or "setpoint" value in the diagnosis.

The PWM value used to control the rail pressure via the control unit is 30-35% of the control signal at full load, and approximately 15% at idle.
Fuel pressure at full throttle is approximately 1300 bar. Should = Is.

According to my assessment, too little fuel is being injected. However, how does this affect the opening times of the fuel injectors?
Other possibilities include incorrect valve timing or a lack of compression.

Coolant temperature is within a reasonable range.
A Lambda monitoring solution does not exist.

Then I would start with the valve timing.

Hello,

Here are some examples of why the engine control unit (ECU) might reduce the fuel injection amount:
- excessively high temperatures for boost pressure, coolant, exhaust gas temperature...
- insufficient air mass/boost pressure.

Best regards, Rainer.

Good evening.

According to my records, it should have a boost pressure of 1.3 bar.

Is the valve clearance correct?

The valves on the engine still need to be adjusted.

Clearance: 0.5 mm.

Best regards,

Michael.

Hi,


Let me see what can be done diagnostically. Does this device have an OBD2 connector?

Best regards, Rainer.

Hey,

1.3 bar? Then, we would be missing 0.5 bar .
Are the data accurate for the 43B engine with 106 horsepower?
I'll take a closer look at the wastegate.

Valve clearance could be an option, but given the low mileage, it's unlikely. Acoustically, at least, there's no indication of that.

Regarding the diagnostic port, it has the 30-pin Iveco connector. I have an adapter to convert it to OBD2.
The engine control unit (ECU) is a Bosch MS6.8 or 6.3.

Unfortunately, the diagnosis was negative. You could try using an OBD-2 scanner if the on-board network is 12V.

Good evening.

The values are for...

8140.43B with 78 KW

Engine with Bosch 6.3 common rail.

According to the manufacturer, it should have a pressure of 1.3 bar.

Check if the rod is still freely movable after such a long period of inactivity.


The components are actually almost all new. Could it be that the voltage values at the control unit are not being received correctly due to corrosion? Are the measured values/parameters on the tester plausible?

During the warm-up phase, it "stalls," exhibits fluctuations in speed, and has no power. When the saw is warm, the blade stops spinning and the speed drops, but it still doesn't have any power?


Do you have an error code?


The sawing and the lack of power have led me to the idea of adjusting the valve clearance. If it was adjusted too tightly, the thermal stress could cause it to no longer seal properly against the valve seat. - However, after 22,000 km, it's unlikely that anyone would have adjusted it.



Best regards,

Michael.

Evening.

Unfortunately, the diagnosis is limited to battery voltage, boost pressure (actual vs. target), fuel rail pressure (actual vs. target), the pump's PWM signal, and throttle position.

The boost pressure was measured and read using an analog system, and the readings match.
I tested the rod using a hand pump, and it moves approximately 1 cm. The movement starts at around 1 bar, and at 1.6 bar, it is 90% open.
Unfortunately, there are no available options to measure the rail pressure.

Do you see the maximum rail pressure in your documentation?

You described the saw perfectly. The fluctuation in RPM isn't visible on the tachometer, but you can feel and hear it. Power loss is constantly present.
If I disconnect either the rail pressure sensor or the coolant sensor, the error immediately disappears. When I reconnect it, it reappears a few seconds later.

Apparently, corrosion on the connectors is supposedly a major weakness in Iveco vehicles, but all the sensors/actuators that have been replaced so far have been found to be in good condition.

Morning,

I have checked the wastegate. It opens at a pressure of 1.1 bar, is very easy to operate, and also provides a good seal.
The pressure vessel can maintain the pressure for a longer period. It is directly controlled by the boost pressure at the turbocharger.
The impeller on the loader rotates very easily, has no play, and shows no damage to the bucket wheels.

In my opinion, either the fuel supply for the turbocharger is insufficient, or the exhaust system (consisting only of a rear silencer) is designed in such a way that the back pressure prevents the turbocharger from reaching higher RPMs.

Hello,

I looked it up for you.

I found your observations in a service information document from Fiat. They use the same engine.

The complaint was that the vehicles lacked power and could only reach higher speeds over longer distances (many kilometers), which were still far from the maximum speed.
The speed was further reduced by uneven surfaces, such as undulations or inclines.

The fuel pressure sensor was responsible for this. It was sending faulty signals due to corrosion.



Fuel pressure sensor: Connect pin A13 to Batt. - Ignition on: 4.5 - 5.5 V.
Fuel pressure sensor: Connect pin A33 to Batt. - Voltage should be 0.8 - 1.2 V when idling.
Fuel pressure sensor, pin A6. Battery connected, ignition on: 0V.

A-pins are the connectors referred to as the ones with the larger connectors/pins when viewed from above, and they are located on the engine control unit.

Pin 1 is located in the bottom left corner, while pin 43 is in the top right corner.



Let me know if you need any other values.


Best regards and have a lovely Sunday.


Michael.

Hello,

Thank you very much for the information .

I was able to confirm all the values from the pressure sensor, so it should be working correctly.
Could you please provide me with the values from the fuel temperature sensor and the torque specification for the injector retaining clips?


I checked the valve timing, removed the injector from cylinder 1, and determined the top dead center (TDC) position using a dial indicator. It fits the camshaft perfectly.

The valve clearance is a bit too tight, at 0.35-0.40mm, which is borderline.

The crankshaft sensor is attached, and it might be causing the problem... it's questionable why it looks like that.

Good evening.

Thank you for the feedback.

The fuel temperature sensor is located at Pin A 15.

When the ignition is off, it should have 0 volts. At a fuel temperature of 20 degrees, it should have 2.6 volts.

At pin A1, the coolant temperature sensor is located.

When ignition is on, 0 volts; at 20 degrees, 2.4-2.8 volts; at 80 degrees, 0.6-0.7 volts.

Both pins A1 and A15 are directly connected to pin A30 of the control unit. That means that if the connection is interrupted, both sensors are interrupted.



Your camshaft sensor is likely not providing accurate readings.
The camshaft sensor connects to pins A4 and A31.
Check the sensor with the oscilloscope.


You can't be much further from the goal.

Best regards,

Michael.

Good evening.

Thank you again for the information!

I'm measuring a fuel temperature of 3.9V, which corresponds to 15 degrees Celsius. This value might be slightly off, but it should still be usable by the control unit.
I haven't been able to measure the coolant yet.
The wiring is at least not interrupted, and the resistance values measured at connector A are the same as those measured directly at the sensor.
With the diagnosis, the coolant sensor at least seemed plausible.

To avoid unnecessary further searching, the crankshaft position sensor will be replaced first. Unfortunately, the exam has been canceled due to a lack of Ozi.
If a false signal were to occur here, it would explain the irregular idle.

To remove the crankshaft position sensor, the turbocharger needs to be removed as well.

Edit:
Besides the coolant sensor, there is another sensor or possibly a switch located in the coolant flange. This sensor does not have a through-hole. Do you have any specifications or values for it? Should that be a temperature switch for the flame start?

Okay, please provide the German text you would like me to translate.