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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Dodge
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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There are NO codes; it has been tested by the MB dealership,

Customer Question

There are NO codes; it has been tested by the MB dealership, an independent MB shop, and Mr. Transmission with their MB diagnostic scanner. All have said that it appears that the turbo is not engaging. Changed turbo vacuum regulator (new) (only 2002 and 2003 have this vacuum regulator, later models have wastegate) after talking with Tim Mohr; Now: actuator arm position retracts downward at engine start up and idle (arm moves freely); voltage at supply wire to actuator at idle is 10.5 -11 volts; at increase in RPM (3000+) the voltage drops to 5-6 volts and the actuator arm position returns (up) to just below the level at engine off (I also have a 2002 Sprinter and this is the same voltage ranges. Also, I switched the vacuum regulators {new 2003 to 2002 and 2002 to 2003 –the 2002 still runs perfect, 2003 still runs poorly}); if the vacuum line from the vacuum regulator to the actuator is disconnected while at 3000+ rpm, the actuator arm position attains an almost vertical position; if the vent is disconnected while running, there is vacuum at the regulator port (bottom of regulator). The Sprinter Turbo still does not engage.
Submitted: 9 months ago.
Category: Dodge
Expert:  Pete replied 9 months ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

If you have not had the EGR checked there were some issues with the EGR valve sticking causing this fault here needing replaced.I have also seen boost hoses at the cooler and leading from the cooler leak causing a boost fault.If these were or are checked and found o.k. let me now before rating my help here so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 9 months ago.
Thank you for the reply. I have had this Sprinter (109,850 miles) for more than a year and it was non-running when purchased. It had not run for 1 1/2 years. It only took about 2 hours to get it running. The engine cranks quickly, and runs great at idle or at acceleration, while parked. I also have a 2002 Sprinter as a motor home that is used also as a daily driver. I have changed many parts from one to the other, and checked the things that you suggested. It seems to accelerate and change gears when cold, but does not do so after 1-2 minutes. I read that the brake tail lights can influence the turbo. there is poor contact with the rear lights. What do you think?
Customer: replied 9 months ago.
I will be unavailable to continue this exchange until about 5:00 PM CST
Thank you,
Expert:  Pete replied 9 months ago.

If there is an issue with the brake switch this can cause this issue here if the switch is sending a false signal that the brake has been pressed when it has not been.If you havent had the fault codes checked with a fully compatible scan tool that can plug in and communicate with all computers this should be done.If any codes are set the codes will help diagnose and locate the fault here.If you can get the codes read out and post them here this will help just let me know.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 9 months ago.
I got back sooner than expected. I have not changed the brake switch. I believe the problem with the rear lights is the contacts that complete the circuit when the rear doors are closed. The rear doors do not close tightly as some of the hardware is missing. The MB dealership, an independent service shop, and the transmission shop all checked and found no codes.
Expert:  Pete replied 9 months ago.

I would have the EGR checked into to see if it is acting up when this issue occurs as well as the brake switch (which is probably o.k. since the doors are not closing properly).

I would also have the boost sensor signals checked for any issues with the sensor or wiring to the sensor and wheel speed sensor signals as sometimes this can cause a fault like this here if you can.If these are all o.k. let me know.

Thanks Pete

Customer: replied 9 months ago.
I do not think that the vacuum actuated turbo has a boost sensor. It has 19 mm of vacuum.The voltage on the vacuum switch to the actuator is 10.5 11 dc volts at idle and 4.5 volts at 3000 RPM on both Sprinters (2002 performs as should, 2003 does not perform well). I do not know anything about the wheel speed sensor. The speedometer reads correctly.
Expert:  Pete replied 9 months ago.

O.k.,unfortunately my info is not matching up to your model here for some reason.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Expert:  Juan Crespo replied 9 months ago.

Hi there. Different expert here.

The key to turbo engagement on this MY Sprinter is a boost pressure vacuum solenoid that is controlled by the ECM using a pulse-width modulated signal or PWM. There are two essential tools used to diagnose this issue; one is a DRB-III or equivalent bi-directional scan tool capable of actuating the vacuum solenoid and displaying boost pressure PID, and the other a scope or very fast voltmeter capable of reading frequency (Hertz); the scan tool is used to command different vacuum settings and monitor the resulting boost pressures and the scope is used to confirm the PWM signals from the ECM.

Dealership techs usually do more than just try to retrieve codes when performing this type of diagnosis. When you state "it has been tested by the MB dealership", do you have a record of what they did? Any data you could share?

Customer: replied 9 months ago.
Thank you for the reply. No I do not have any information from the tests. The dealership said that there were no current of past codes; The independent MB shop did not find any codes either, but sais that the problem may have to do with the fuel pressure; The transmission shop checked the transmission, which had no codes and they said the quick shifting was caused by the turbo not engaging. I do not have any tool except a OBC II/ABS.
I checked the vacuum (19 - 22) and it and sends vacuum (19) to the actuator. The actuator arm moves downward (retracts) when the engine cranks. It returns to engine off position when RPM increased (3000+). The voltage is 10.5 -11 dc volts at idle and 4.5 dc volts at 3000+. Since the voltage is changing with RPM changes, is that not an indication that it is getting signal from the ECM?
Expert:  Juan Crespo replied 9 months ago.

Looks like you don't have access to the tools you would need to perform the procedures that would allow us to diagnose this issue, so I'm afraid I won't be able to help you. I'll opt out so others may try. Please do not rate or reply until another expert responds or the site will cycle this back to me.

Customer: replied 9 months ago.
Hello Juan, I purchased a high speed digital volt meter that has the range of 0 - 200kHz. Now I need to know what I should check with it.
Please respond. Thank you, Pat