AfterMarketNews Auto Care Pro AutoProJobs Auto-Video.com Brake&Frontend BodyShopBusiness Counterman EngineBuilder Fleet Equipment ImportCar Motorcycle & Powersports News Servicio Automotriz Shop Owner Tire Review Tech Shop Tomorrow's Tech Underhood Service

Second-rate parts mean second-rate results

When it comes to diagnosing a problem, one of the biggest mistakes is thinking that the problem is gone after you’ve installed a new part. I’ve had vehicles brought in countless times with the same old story attached to them. The customer will say:...

Read more...

GearWrench Launches Street Team, a New Mobile Driver Program

GearWrench, a premier hand tool brand from Apex Tool Group, has announced Street Team, a new program that gives independent mobile distributors the support of an established tool brand without the restrictions of a franchise. "Response to the program...

Read more...

AUTO 7 Named Approved Vendor For Automotive Parts Associates

Steven Kruss, president of Auto 7, which supplies Korean-made, OEM-quality automotive parts to distributors across North America, announced that Auto 7 has been named an approved vendor of Automotive Parts Associates (APA), one of the nation’s...

Read more...

Internal Engine Oil Consumption Diagnostics

Due to the variables in engine design and ­operating conditions, internal engine oil ­consumption complaints are often the most difficult to solve. In some cases, oil consumption might be more severe under low-speed operation, in other cases, high-speed...

Read more...

Hyundai Fuel System, Emissions Diagnostics

Hyundai has done a good job of improving its ­offerings over the years from both an aesthetic and mechanical viewpoint. Complemented by a strong warranty and good value, the carmaker has been able to increase its market share year over year. If you aren’t...

Read more...

Curing Volvo Manual Transmission Rattle

In an effort to increase fuel efficiency, today’s engines produce more torque so they can be ­driven at extremely low rpm. ­Reduced viscosity engine and gearbox oils, less vehicle weight and improved aerodynamics also contribute to better fuel economy....

Read more...

Servicing The Electronically Adjustable Shocks Of Full-Sized GM Trucks

Since the 2000 model year, GM has offered electronically adjustable suspension as an option on Chevy, Cadillac and GMC full-size trucks. The system actuates the valving in the shocks to control ­suspension position and body attitude. The electronic...

Read more...

Diagnosing Clutch Assembly Noises

Noise can resonate from many areas of a ­vehicle’s driveline. There are several types of noises associated with the clutch assembly. The release bearing is most often blamed for being the cause of noise when, in many cases, it is not the release...

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...

Talk To All Available Modules With Autel's MaxiDiag Elite MD802

Derived from Autel’s Professional Series tool, the MaxiDAS DS708, the MaxiDiag Elite MD802 enables the user to not only get into the OE enhanced OBD II system with mode 6 access and live data graphing, but it also allows a technician to scan the...

Read more...

Reflashing & Reprogramming Tools

In the first half of 2014, NHTSA has issued more than 15 recalls where the fix was to reflash a module on a vehicle. In the same time frame, more than 100 TSBs have also been issued where the solution is to reflash a module. These recalls and TSBs...

Read more...

Pulling Codes: An Advanced Misfire Story The Story of P0301

This article will document code P0301 — Misfire Activity on Cylinder No. 1 — a code many of you have run into, but sometimes we have case studies that are worthy of mention. Our subject vehicle is a 2007 Mercury Mountaineer. The vehicle has...

Read more...

Home Engine Jeep Fuel Problems Needn’t Be an Uphill Battle

Print Print Email Email

Since its debut at the 1992 North American International Auto Show in Detroit, the Jeep Grand Cherokee has been a dependable vehicle for many vehicle owners.

Most of the early models (1993-1998) were powered by either an in-line 4.0L six-cylinder engine, or the larger 5.2L and 5.9L V8 Magnum engines. In fact, the Grand Cherokee 5.2L V8 made both the Car and Driver magazine’s "Ten Best" list, as well as Motor Trend magazine’s "Truck of the Year" for 1993.

Over the years, the vehicle saw some changes to both the body and the V8 engine. The second-generation of the Grand Cherokees (1999-2004), still had the 4.0L I6, but the V8 Magnum engine was replaced with a 4.7L PowerTech V8.
In 2005, a 3.7L V6 engine replaced the earlier I6 powerplants, and 5.7 V8 Hemis were made available under the hood, as well as a more powerful 4.7L PowerTech.

Grand Cherokees are prone to having some common mechanical problems, and many of you have probably serviced complaints of noisy differentials. While it is acceptable for Jeep differentials to make some noise, it’s not wise to ignore noises that are more than moderate or if your customer tells you that noise is noticeably getting louder as they rack up the miles.

Another common issue that puts Jeeps in repair shops is fuel pump related. In this article, we’ll address some fuel system complaints that have plagued these vehicles.

Technicians using Identifix have identified a repeated failure of a new fuel pump that’s due to either a film on the interior of the fuel tank that contaminates the fuel, or from a residue left in the fuel tank from a previously failed fuel pump.

This is a common occurrence to the 1993-’98 Jeep Grand Cherokees with the 4.0L and 5.2L engines, as well as 1998 models powered with the 5.9L engine.

To test the system, Identifix staff recommends you a take a fuel sample in a clean, clear jar. Check the fuel for a cloudy appearance. If the fuel looks cloudy, either the interior lining of the fuel tank is dissolving into the fuel or a residue left from the failed fuel pump is contaminating the fuel. Jeep has never really commented on the true cause.

The most reliable way to avoid repeated fuel pump failure for your customer is to replace the fuel tank and use fresh fuel.

Also, there have been some intermittent misfire issues — especially under heavy load with less than half a tank of fuel — on 1999-2002 4.7L, 5.2L and 5.9L Jeep engines. On these engines with the returnless fuel system, you may come across DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0309 and P0310.

If the symptoms only occur when there is less than a half tank of fuel, check the fuel pump volume. Hook up a fuel pressure gauge with a drain valve and hose to the fuel rail.

Next, start the engine and fully open the drain valve to let the fuel run into a suitable container. The system should pump at least 1 pint (or 1/2 liter) of fuel in 15 seconds. There should not be any air bubbles in the fuel, either.

If the test fails, remove the in-tank fuel pump. Replace the pump assembly or just the inlet
filter, and clean out the tank.

Rough/No Starts
A TSB from Jeep released in July 1997 to address the film buildup issue in more detail goes as follows:

Symptom/Condition
Symptoms may include no start, rough idle, long crank times, driveway die outs or erratic fuel pressure. A new fuel pump has been released, which delivers improved performance. This pump should be used whenever fuel pump failures are encountered.

Diagnosis
Basic fuel system diagnostics should be used as outlined in the appropriate service manual. A brief recap of the basic diagnostics follows:

Fuel pressure specification — 49 psi – plus or minus 5 psi.

High fuel pressure indicates problems with the fuel pressure regulator. Refer to the service manual for regulator diagnosis. Do not replace the fuel pump for high pressure.

Low fuel pressure — Low pressure could indicate a pump problem or it could indicate a plugged fuel filter or restricted fuel line or no fuel in the tank. Be sure to check these items before replacing the fuel pump.

Fuel system leak down — When checking fuel pressure be sure to check the integrity of the system after shut down. With the fuel pressure gauge connected, shut the engine off and observe the pressure gauge. The system should maintain at least 24 psi for five minutes after shut down. If the pressure bleeds off quicker, it could indicate that an injector is leaking down or that the pressure regulator is leaking. This can lead to driveability problems and require further diagnosis.

Fuel Filter/Fuel Pressure Regulator Replacement on 5.2L Engine
Fuel filter replacement is a preventive maintenance procedure your shop will need to provide. The following is the procedure to service a 1998 Jeep Grand Cherokee (4WD) 5.2L engine.

The combination fuel filter/fuel pressure regulator is located on the fuel pump module. The fuel pump module is located in the top of the fuel tank. The filter/ regulator may be removed without removing the fuel pump module, although the fuel tank must be removed.

Removal
1. Remove the fuel tank.
2. Clean the area around the filter/regulator.
3. Remove the retainer clamp from the top of the filter/regulator (see Figure 1). The clamp snaps to the tabs on the pump module. Discard the old clamp.
4. Pry the filter/regulator from the top of pump module with two screwdrivers. The unit is snapped into the module.
5. Remove and discard the gasket below the filter/regulator (see Figure 2).
6. Before discarding the filter/ regulator assembly, inspect the assembly to verify that the O-rings (Figure 3) are intact. If the smaller of the two O-rings cannot be found on the bottom of the filter/regulator, it may be necessary to remove it from the fuel inlet passage in the fuel pump module.

Installation
1. Clean the recessed area in the pump module where the filter/regulator is to be installed.
2. Obtain the new filter/regulator (two new O-rings should already be installed).
3. Apply a small amount of clean engine oil to the O-rings. Do not install the O-rings separately into the fuel pump module. They will be damaged when installing the
filter/regulator.
4. Install the new gasket to the top of the fuel pump module.
5. Press the new filter/regulator into the top of the pump module until it snaps into position (a positive click must be heard or felt).
6. The arrow (Figure 1) on top of the fuel pump module should be pointed toward the front of the vehicle (12 o’clock position).
7. Rotate the filter/regulator until the fuel supply tube (fitting) is pointed to the 11 o’clock position.
8. Install the new retainer clamp (clamp snaps over the top of the filter/regulator and locks to the flanges on the pump module).
9. Install the fuel tank.

Source: ALLDATA

Fuel Filter Service on 4.0L Engine
For fuel filter removal and installation on the 1996 Jeep Grand Cherokee (4WD) 4.0L I6 engine, follow this procedure:
Note: The fuel system is under constant pressure, even when the engine is off. Always release fuel pressure before servicing any fuel system component.

Removal
1. Disconnect the negative battery terminal, and remove the fuel tank cap.
2. Raise and support the vehicle for access.
3. Remove fuel filter hoses and clamps from the inlet and outlet fuel nipples. Remove the retaining strap bolt, and remove the filter.

Installation
1. Install the new filter in the retaining strap. Check the direction of flow by the markings on the filter, and ensure it is correct.
2. Install the retaining strap bolt, and torque to 12 Nm (8.8 lb-ft) as seen in Figure 4.
3. Install the inlet and outlet hoses, and clamps. Tighten the clamps securely. Lower the
vehicle. Reconnect the negative battery terminal.
4. Using the DRB II select the Automatic Shut Down (ASD) Fuel System Test to pressurize the fuel system and check for leaks. Refer to Powertrain Management / Computers and Control Systems / Testing and Inspection / Procedures.  

Caution: Unless the test is stopped or the ignition switch is turned to the off position, the fuel pump relay and the ASD relay will remain energized for seven minutes by the ASD Fuel System Test.  

Source: ALLDATA 

Advertisement
Advertisement
Advertisement
Advertisement
Latest articles from our other sites:

PaceSetter Performance Products Offers California Legal Direct-Fit Catalytic Converter For 1999 Volkswagen Beetle, 2.0L Engine

PaceSetter Performance Products, designers and manufacturers of quality-made, affordably-priced exhaust systems and components, now offers a direct-fit catalytic converter for the 1999 Volkswagen Beetle...More

Spectra Premium Announces Engine Management Customer Satisfaction Warranty

Spectra Premium Industries has announced a new customer satisfaction warranty on its mass air flow sensors, ignition coils, distributors, cam and crank sensors and synchronizers, effective immediately. Spectra...More

Internal Engine Oil Consumption Diagnostics

Due to the variables in engine design and ­operating conditions, internal engine oil ­consumption complaints are often the most difficult to solve. In some cases, oil consumption might be more severe...More

Hyundai Fuel System, Emissions Diagnostics

Hyundai has done a good job of improving its ­offerings over the years from both an aesthetic and mechanical viewpoint. Complemented by a strong warranty and good value, the carmaker has been able to...More

Avoid The 'Warped Rotors' Trap, Find True Pulsation Cause

The expression “warped rotors” still seems prevalent in the brake service community. According to common lore, a warped rotor is the usual cause for pedal pulsation or vibration in the car or steering...More

Getting An Accurate Toyota Tire Pressure

Ambient temperature changes can dramatically alter tire pressure, which could cause a tire pressure monitoring system (TPMS) warning light to illuminate. The TPMS must be initialized based on the tire’s...More

OTC Releases Smart Battery Tester

OTC has launched the 3200 Smart Battery Tester, offering near-instant battery, charging and starting system test results with a technician’s iOS or Android device. The tester clips onto a battery’s...More

Ernst Offers Socket Boss Universal Twist Lock Socket Tray

Versatility is a must for organizing any socket set. Capitalize on maximum configuration possibilities with the new Universal Twist-Lock Socket Tray from Ernst. Individual rails can be removed or switched...More