ToadToe

My 1998 Dodge 2500, 12-valve Cummins has developed a quirk when towing my 7-ton, 5th wheel trailer. While running perfectly to begin with, after an unspecific period of time and miles, the turbo boost starts to run cyclically when any power/boost is required. The boost goes up and then immediately drops off to zero and stays there for about 3-5 seconds. Keeping the foot on the accelerator, the boost comes back up and the cycle repeats. On my last recent trip, it ran perfectly for the first few days and then started doing this on the last three, near the end of each day. Engine, transmission and exhaust temperatures stay normal. Last Spring I traveled almost 4,000 miles and it only started acting up on the end of the last two days. I have no clue on what’s causing this, or how to correct it.

BigIron70

Waste gate actuator read service bulletin.

NO: 11-08-98

SUBJECT: Turbo DieselWastegate ActuatorRepair Kit

DATE: Sep. 25, 1998

NOTE: THIS INFORMATION APPLIES TO VEHICLES EQUIPPED WITH A 5.9L DIESEL ENGINE.

DISCUSSION:

A new kit has been released that will allow technicians to repair turbochargers with failed wastegate actuators. Wastegate actuators that have failed can cause low power complaints or noise complaints from air escaping out of the actuator.

DIAGNOSIS:
1.Remove the air supply (signal) line from the wastegate actuator (Figure 1).
2.Install a regulated air supply to the actuator (Figure 2).
3.Spray the actuator assembly with a soap solution and apply regulated shop air not exceeding 310 KPa (45 psi) to the actuator.

NOTE: DO NOT EXCEED 310 KPA (45 PSI).
4.If an air leak can be heard or bubbles are seen exiting from the actuator, perform the Repair Procedure.
5.If an air leak is not detected and the actuator rod does not move, remove the e-clip at the end of the actuator rod. Carefully disconnect the rod from the crank arm and check the crank arm for free movement. If the crank arm is seized or does not move easily, replace the turbocharger assembly.

PARTS REQUIRED:


Qty Part No. Description
1 05013666AA Kit, Actuator 1996/1998 12 Valve Diesel (California Emissions Automatic/Manual)
1 05013667AA Kit, Actuator 1995 (See Note) - 1996/1998 12 Valve Diesel (Federal Emissions Automatic)
1 05013668AA Kit, Actuator 1996/1998 12 Valve Diesel (Federal Emissions Manual)
1 05013669AA Kit, Actuator 1994 (All) - 1995 (See Note)
1 05013670AA Kit, Actuator 1998 24 Valve Diesel (All)


NOTE: TO DETERMINE CORRECT KIT USAGE FOR 1995 MODELS, VERIFY IF THE WASTEGATE ACTUATOR HAS A SHORT (APPROX 1 FT) TURBO-MOUNTED AIR SUPPLY (SIGNAL) LINE, OR IF IT HAS THE LONGER (APPROX 3 FT) ENGINE-MOUNTED AIR SUPPLY LINE.

USE P/N 05013667AA FOR SHORT, TURBO-MOUNTED CONFIGURATIONS.

USE P/N 05013669AA FOR LONG, ENGINE-MOUNTED CONFIGURATIONS.

REPAIR PROCEDURE:

This bulletin involves removing the failed wastegate actuator and replacing it with a new part.

NOTE: THE NEW WASTEGATE ACTUATOR WILL BE PRESET WITH A SPACER AND JAM NUT (FIGURE 3). INSPECT THE JAM NUT PAINT WITNESS MARK TO MAKE SURE THE SETTING HAS NOT CHANGED. IF THE SETTING HAS CHANGED, RETURN THE KIT FOR A NEW ONE.
1.Following service manual procedures, remove the turbocharger from the vehicle.
2.Remove the air supply hose from the actuator and connect regulated shop air to the actuator (Figure 2).

NOTE: DO NOT APPLY MORE THAN 310 KPA (45 PSI) INTO THE ACTUATOR.
3.Remove the e-clip that attaches the wastegate actuator end link to the turbocharger crank arm.
4.The end link can now be easily removed from the crank arm.

CAUTION: THE ACTUATOR ROD MAY RETRACT WITH FORCE INTO THE ACTUATOR IF SHOP AIR DOES NOT RELIEVE THE TENSION. KEEP HANDS AND FINGERS CLEAR WHEN PRYING THE END LINK FROM THE CRANK ARM.
5.Remove shop air from the actuator and remove the actuator from the turbocharger.
6.Thread the new end link (from kit) 4 or 5 turns onto the new actuator.
7.Fit the end link over the crank arm with the solid edge of the spacer facing away from the actuator mounting bracket. Push the crank arm toward the actuator (Figure 4).

NOTE: DO NOT FIT THE ACTUATOR STUDS INTO THEIR MOUNTING HOLES AT THIS TIME.
8.Adjust the end link by rotating it on the actuator shaft until the body of the actuator just clears thebracket with less than 0.5 mm (0.020 in) clearance (Figure 5).

NOTE: THE ACTUATOR BODY MUST NOT BE FORCED TO CLEAR THE MOUNTING BRACKET.
9.While holding the end link from rotating, remove the end link from the crank arm.
10.Install the actuator studs through the mounting holes of the bracket and install the end link to the crank arm.
11.Attach the end link to the crank arm with the new e-clip (from kit) and install the new actuator mounting nuts (from kit) onto the actuator studs. Torque the nuts to 8.5 Nm (75 in lbs.).
12.Loosen the jam nut that holds the spacer in place. Cut the tie strap, remove and discard the spacer.
13.Tighten the jam nut against the end link. Torque the nut to 8.5 Nm (75 in lbs.).
14.Connect the air supply line onto the actuator and secure it with a new hose clamp (from kit).
15.Following service manual procedures, reinstall the turbocharger assembly to the engine using the new gaskets (from kit).

BigIron70

Here is turbo test location

ToadToe

Thanks for the detailed answer, BigIron70, but I still have a question: My problem comes after driving a while. Before that, the turbo boosts perfectly, no lag. Is this typical of a waste gate failure?

gorms

I would say an intermittent boost loss is not typical of a wastegate failure but anything is possible, easy enough to check. I'm guessing power is down while boost drops, does it act any different if you give it more or less throttle? Make sure your shutdown solenoid is working properly and the linkage isn't sloppy or binding.


I'd check fuel pressure with an in cab gauge, overflow valve or lift pump certainly could act up when hot. So could injector pump internals....check the easy things first.

AlpineRAM

So, you see a loss of boost, stay on the pedal, and there is no difference in power or EGT?

If so - what kind of boost gauge do you use?

(Reason for asking- had a guy with a westach combo gauge complaining about similar problems, it was a loose ground connector in the wiring)

ToadToe

I had the waste gate actuator replaced since it sounded like the best solution presented. Final got the truck and trailer out to test it. Drove 150 and 125 miles on consecutive days without a problem. On the way back in one day, the problem was back after about 200 miles. Same exact thing, although while away, the turbo cycling began for the first and only time without towing. It started after trying to acccelerate quickly to merge with traffic. I had been running errands, so the engine was up to temperature. I'm sure boost had run up to limit, but was not watching gage.

torquefan

I just want to clarify the problem you're describing, your truck is suffering a loss of power while under a big load. The loss of power is cyclical and lasts a few seconds before correcting itself, then the cycle repeats. Correct?

Is the transmission an automatic? If so, what does your tachometer do when this condition occurs, does it jump right up to 3000 RPM? When you described the cyclical nature, the first thing that occurred to me is that the transmission is shifting in and out of overdrive, or perhaps just lockup. It's pretty common, and at highway speeds with a heavy trailer on, it'll be really noticeable as a loss of power, especially if it causes the RPM to jump right up to red line.

Have seen a worn out throttle position sensor cause stuff like this, but it will take some more diagnostic work for you to determine if this may be what's actually going on. Let us know if it sounds like a possibility.

ToadToe

Torquefan, Your description of my problem is correct except for only minor details. The entire cycle is about 15 seconds and is the same no matter how much power I give the truck when the power comes back on. (I wish I had done some videos while this was going on.) However, the automatic transmission does not rev up at any time. Engine speed just follows the power loss and the revs just go down accordingly. It feels more like a lack of fuel, making some suggest lift pump pressure, but there is never a change in the cycle, even when I back off as the power comes back on. I feel that there must also be a correlation with the temperature of some component because it never happens until after a long period of running, even though water, transmission and exhaust gas temperatures stay perfect.