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Andy
Andy, Truck Diagnostic Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1571
Experience:  International trucks, International, Maxxforce and Cummins engines, diagnostic, electrical, Hvac and refrigeration repairs
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We have a 2006 International 4300 series truck,came into the

Customer Question

Hello Pearl,we have a 2006 International 4300 series truck,came into the shop for a low power problem,scanned for codes and test drove,no codes until we started up a long steep hill,lost power and ck. engine light came on,rreturned to the shop and found a code # 353 was active.I visited with the client,it seems to be an intermittent problem as we had the truck in here 2 wks. ago,replaced the fuel filter and test drove,truck ran ok,now it has returned for low power,
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Heavy Truck Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the Heavy Truck Mechanic should know?
Customer: I read the response to a similar problem someone else had and checked a few steps he suggested and droveit again,checked fuel pressure,reading was 59 psi while driving,performed the pre-cycle test,linkage moved the first time,did not move the next two times,rod retracted completely and did not rreturn to the previous position.Thanks for your help in resolving this problem.
Submitted: 5 months ago.
Category: Medium and Heavy Trucks
Expert:  Andy replied 5 months ago.

Hi there ! My name is ***** ***** Can we start with the last 8 digit of the vin number please ? Is 353 the only fault found in the history ?

Expert:  Andy replied 5 months ago.

Do you still need help ?

Expert:  Andy replied 5 months ago.

The Variable Geometry Turbocharger (VGT) has actuated vanes in the turbine housing. The vanes modify flow characteristics of exhaust gases through the turbine housing. The benefit is the ability to control boost pressure for various engine speeds and load conditions.

The VGT is a closed loop system that uses the Exhaust Back Pressure (EBP) sensor to provide feedback to the Electronic Control Module (ECM). The ECM uses the EBP sensor to continuously monitor EBP and adjust the duty cycle to the VGT to match engine requirements.

The VGT actuator is a control module that contains a microchip and a DC motor. The VGT actuator is located below the turbocharger. The microchip operates a DC motor which rotates a crank lever controlling the vane position in the turbine housing. The position of the vanes is based off the pulse width modulated signal sent from the ECM.

Actuated vanes are mounted around the inside circumference of the turbine housing. A unison ring links all the vanes. When the unison ring moves, all vanes move to the same position. Unison ring movement occurs when the crank lever in the control module moves.

Exhaust gas flow can be regulated depending on required exhaust back pressure for engine speed and load. As demand for EBP increases, the ECM increases the pulse-width modulation to the VGT control module. When EBP demand decreases, the ECM decreases the duty cycle to the control module.

Actuator control for the vane position is achieved by setting a pulse width modulated signal from the ECM in response to the following:

  • Engine speed
  • Desired fuel quantity
  • Boost
  • Exhaust back pressure and altitude
Expert:  Andy replied 5 months ago.

Customer, this is likely going to have to do with turbo linkage binding or pivot flange seizing up in the turbo .

Expert:  Andy replied 5 months ago.

Do you still need help with this ? We can go through the bonce test and the precycle test together with a hot engine an see if the linkage is the problem .

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