AfterMarketNews Brake&Frontend BodyShopBusiness Counterman EngineBuilder Fleet Equipment ImportCar Motorcycle & Powersports News Servicio Automotriz Shop Owner Tire Review Tech Shop Tomorrow's Tech Underhood Service Speedville

Fuel Trims And AFR Sensors

Fuel trims are a difficult topic to cover in a matter of a few pages. But this summer, an old friend and former teaching partner arrived at our local car show with the check engine light illuminated on his 2004 Holden Monaro, which was imported from...

Read more...

Preventive Maintenance Profits: Preferred Automotive, Jenkintown, PA

With the summer months heating up and cross-country road trips beginning, many people want to make sure their vehicles are prepped for the long haul. For the first-ever July edition of Maintenance Chronicles, we will focus on Preferred Automotive Specialists,...

Read more...

Toyota Charging System Diagnostics

According to my experience, I estimate that replacing the alternator solves 95% of all charging system failures. If that’s true, what happens in the remaining 5% of charging system failures that results in customer comebacks? To explore charging system...

Read more...

Making Sense Of Steering Angle Sensor Input And Data

Measuring the­ ­position angle, rate of turn and force of the steering wheel is critical for Electronic Stability Control (ESC) systems. Scan tools call these Steering Angle Sensors (SAS) and typically display the information in degrees. The SAS...

Read more...

Rotor Failure: Why Rotors Crack And Make Noise

The prices of rotors seem to be dropping the past few years. Call just about any parts supplier and they can quote you a vast range of prices for the same application. And when you compare the rotors side-by-side, they may look the same, but the difference...

Read more...

Tire Tread Wear: Causes And Symptoms

Understanding Tire Tread Wear Tire tread wear can tell you a lot about a suspension. Most specifically, it can tell you if the angles, inflation and components are within specification. Here are the most common tread wear patterns and what causes them. Over-inflated...

Read more...

The Ins And Outs Of Sanders

Sanders are required tools in today’s collision repair shop. Body techs and painters rely upon them every day to achieve that perfect finish on your customers’ vehicles. Whether you’re prepping a panel for paint or removing imperfections before...

Read more...

Are You Regularly Maintaining Your Equipment?

Technicians who are idling because the welder won’t feed wire, the hydraulic ram won’t pull chains, the booth heater won’t heat or the air compressor won’t compress enough air is a costly mistake, as labor time is the most expensive thing in any...

Read more...

Celebrate 'Back To The Future' Day By Watching The Time Machine Get A 2015 Detail

    For many today is just another Wednesday, but for a lot of people it is more than just your average Wednesday, it is "Back to the Future" Day. It is a day that everyone who watched the cult classic trilogy Back to the Future recognizes...

Read more...


Home Emissions Tech Tip: Multiple Cylinder Misfire or Rough Idle on Chrysler Models

Print Print Email Email

This bulletin involves rotating all ­engine exhaust valves, replacing the valve spring retainer locks with a new design to increase valve rotation at lower rpm, inspecting/replacing the MAP sensor (as necessary), and decarbonizing the combustion chamber.

Models: 2004-’06 Pacifica (CS) and 2005-’06 Chrysler 300/ Magnum/Charger (LX)

Note: This bulletin applies to CS models built after Feb. 1, 2004 (MDH 0201XX) equipped with a 3.5L engine (Sales Code EGN).

Symptom/Condition
The customer may experience occasional engine misfire (rough-running engine) during certain
vehicle operating conditions.

In addition, MIL illumination may also have occurred due to DTC P0300 – Multiple Cylinder Misfire. Various single cylinder misfire DTCs may also be present. If the frequency of misfire is high, the powertrain control module (PCM) may place the engine in “limp-in” mode.

The misfire condition may be caused by one or more engine exhaust valves that are slow to close due to a buildup of carbon on the valve stem.

Diagnosis
1. This condition may occur when the engine is not allowed to run at engine rpms that are greater than 3,500. At 5,000 rpm or higher, the engine exhaust valves will rotate if not impeded by high carbon deposits. Low engine rpms and high carbon deposits are associated with short-trip driving where the engine is not allowed to fully warm to normal engine operating temperatures.

Cold ambient temperatures will increase engine warm-up time and increase the likelihood of carbon deposit buildup on the stem of the engine exhaust valve. Fuel detergent quality may also contribute to the condition; the customer may want to try a different brand of fuel.

2. Verify that the engine misfire condition is not caused by faulty engine mechanical or electrical components.

3. If the engine mechanical and electrical systems are operating properly, perform the Repair Procedure.

Repair Procedure
Valve Rotation:

1. Relieve the fuel pressure.

2. Remove the upper intake manifold.

3. Remove the cylinder head cover(s).

4. Remove the rocker arm and shaft assembly.

5. Clean and mark the tip of each exhaust valve stem at the 12 o’clock position with a paint marker. The paint mark will be used later to assist with determining the amount of valve rotation.

6. Remove the spark plugs.

7. Rotate the crankshaft clockwise, until the number 1 piston is at Top Dead Center (TDC) on the compression stroke.

8. Install the compression tester spark plug adapter in cylinder #1 spark plug hole. With the air hose attached to the spark plug adapter, apply 620.5 to 689 kPa (90 to 100 psi) air pressure. This is to hold the valves into place while servicing the components.figure 1

9. Using a valve spring compressor tool (MD 998772A) with the valve spring adapter (6527 or equivalent), slightly compress the exhaust valve spring to release tension against the valve and valve spring retainer (see Figure 1).

10. Remove the valve spring retainer locks and discard the locks.

Note: It is important that the valve rotation section of this repair procedure be performed.

Caution: Only grab the valve stem tip, being careful not to cause damage.

11. Using needle-nose pliers, grab the tip of the valve stem and rotate the exhaust valve 90° (move the mark to the 3 o’clock position).

12. Install two new valve spring retainer locks (P/N 53022277AA).

13. After installing the locks, release the tension on the valve spring and verify proper installation.

14. Remove Special Tool MD 998772A (1) and the spark plug adapter tool.

15. Repeat steps 7-14 on the remaining five cylinders using the firing sequence 1-2-3-4-5-6. Make sure the piston is at TDC in each cylinder of the exhaust valve spring retainer lock that is being removed. When all the exhaust valves have been rotated 90° and all the exhaust valve spring retainer locks have been replaced, proceed to the next step.

16. Install the rocker arm and shaft assembly.

17. Install the cylinder head cover(s).

18. Install the upper intake manifold figure 2

MAP Sensor Inspection:
1. Inspect the MAP sensor — Figure 6 for LX models or Figure 3 for CS models.

a. If the MAP sensor is the new style, no further action is necessary for the MAP sensor. Proceed to Decarboning Combustion Chamber and Valves.

b. If the MAP sensor is the old style, proceed to the next step.

2. Replace the MAP sensor with P/N 05033310AC for LX models or P/N 04896003AB for CS models. If the vehicle is a CS model, be sure the new sensor opening is facing a downward direction when installed and only use one fastener.

When complete, proceed to Decarboning Combustion Chamber and Valves.

Decarboning Combustion Chamber and Valves:
Caution: Do not use the Premium Air Intake Cleaner provided with kit 05174566AA for this service action.

Note: Use both fuel tank additives.

1. Pour the Premium Fuel System Cleaner from kit P/N 05174566AA and Combustion Clean P/N 05183546AA, into a full fuel tank.

2. Start the vehicle’s engine and allow it to reach normal operating temperature.

3. Disable the fuel pump by removing the fuel pump relay.

4. Disconnect the fuel supply line quick disconnect fitting from the fuel rail.

5. Install the appropriate adapter, either #31814 or #31815. Be sure to engage the adapter completely (push until a “click” is noticed).Figure 3

6. Pour the Premium Combustion Chamber Cleaner from kit P/N 05174566AA, into the cleaning
canister.

7. Suspend the fuel injector cleaning apparatus under the hood. The regulator knob must be fully counterclockwise to the off position. Connect the cleaning apparatus service hose to the supply adapter.

8. Turn the regulator knob clockwise to the recommended cleaning pressure (58 psi). Be sure there are no leaks before starting the engine.

9. Start the engine and run at normal idle (or fast idle, 1,200-1,500 rpm, to shorten service time) until the product has been used up and the engine stalls.

10. When the engine stalls, turn the ignition off.

11. Disconnect the cleaning apparatus and adapter.

12. Reconnect fuel line and the fuel pump relay.

13. Turn the ignition key to the on position to energize the fuel pump. Check for leaks. Start the engine and run for at least 2 minutes to clear the fuel system of any residual product.

14. Using the DRBIII or the Star-SCAN, erase any engine DTCs.

Road Test:
1. In a safe vehicle operating location that will allow the vehicle to be driven safely and at the posted speed limit, accelerate the vehicle until the engine reaches 4,500 rpm.

2. Hold the engine speed at this rpm for 15 seconds.

3. Slow down and, in a safe location, pull to the side of the road. Allow the engine to idle for five ­seconds.

4. Repeat steps 1 through 3 five more times.

Courtesy of ALLDATA.

The following two tabs change content below.
Underhood Service Staff Writers

Underhood Service Staff Writers

Latest articles from our other sites:

CARDONE Introduces Remanufactured Drive Axle Assemblies

CARDONE Industries has announced the release of remanufactured drive axle assemblies. Offered as a complete assembly and priced significantly lower than new, CARDONE drive axle assemblies are the perfect...More

Hybrid Service Training

If you are turning away hybrid vehicle service, change that mindset right now. With more than 4-million hybrid vehicles sold through April 2016, service opportunities exist if you welcome them and are...More

CARDONE Introduces Remanufactured Drive Axle Assemblies

CARDONE Industries has announced the release of remanufactured drive axle assemblies. Offered as a complete assembly and priced significantly lower than new, CARDONE drive axle assemblies are the perfect...More

Federated Awards Jeep Grand Prize During Federated 400 Festivities

There was more excitement than usual in the Federated 400 hospitality area at Richmond International Raceway this year. Tim Hicks of Don Hicks Auto Service in Sandy Lake, Pennsylvania, was awarded a...More

Alert Stamping's 8W COB Light Features a 50’ Cord

The 5050CL8 900 Lumen, 8W COB Light Reel from Alert Stamping features a 50’ 18/2 SJT cord, an integrated magnet and folding swivel hook. Soft comfort hand grips and a power “On” indicator...More

Handheld Digital Tire Inflator from AME International

AME International announces the release of its Accu-Flate XL, a handheld digital tire inflator. The Accu-Flate XL measures, inflates and deflates tires with advanced precision and is for use in the...More