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

ASE G1: Drive Belt Inspection, Replacement

The ASE G1 Certification test contains 55 scored questions, plus 10 unscored ­research questions, that cover a range of skills and knowledge related to maintenance and light repairs in engine systems, automatic transmission/transaxle, manual drivetrain...

Read more...

Amateurs and Hacks Provide Job Security For Automotive Service Professionals

Two cars pull up in front of my shop. The drivers didn’t come in, but I heard the commotion from my office window. The boyfriend opens the hood of his girlfriend’s car. They both stare at the engine; she tells the boyfriend that she was supposed...

Read more...

ASE A5: Brake Fluid and Bleeding Sequence

The ASE A5 Test includes a portion on brake fluid, bleeding, flushing and leak testing. You must know how to: • Diagnose poor stopping, pulling, dragging, or incorrect pedal travel caused by problems in the brake fluid; determine needed repairs. •...

Read more...

Inside Import Car Collision Warning, Automatic Braking Systems

Anything that moves under its own power also has to stop, so brakes have been a safety feature on cars since day one. Over the years, technical innovations such as antilock brakes (ABS) have ­improved the ability to stop with minimal skidding on...

Read more...

Intermittent Engine Misfire Analysis

Even for an experienced diagnostic technician, ­attempting to diagnose an intermittent misfire ­condition that occurs only under specific driving conditions can be a frustrating exercise. Let’s begin by getting the basics out of the way. As we know,...

Read more...

Honda: Easy Fix for Engine Noise

We often encounter engines that have a cold-start knock or ticking noise. In this case, the 3.5-L V6 engines installed in various Honda models can make a knocking or ticking noise at idle and only when warm. The cause of the problem is that the rocker...

Read more...

Using Recalls, TSBs as Brake Job Tools

You are getting ready to perform a brake job on a vehicle. While checking the torque specifications on the vehicle, you decide to hit the tab with TSBs and recalls. All of a sudden you are staring at a screen of brake recall notices and TSBs for that...

Read more...

Causes of Clutch Failure: Diagnosing Chatter

One of the most difficult clutch-related problems is chatter. Chatter is sometimes difficult to diagnose because it has many root causes, and some of them may not seem related at first. Chatter can be detected as a pulsing or a grabbing sensation that...

Read more...

GM: Simple Steering Noise Fix

Before you replace that Chevrolet Avalanche steering rack because of a variety of strange noises — wait. There might be a very simple repair. Owners of the GM truck and SUV models listed below may comment that they are hearing a pop, click or clunking...

Read more...

5 Tool Storage Tips

  As a technician, you likely own thousands of dollars worth of tools and equipment, and require tool storage capacity to hold them all, along with carts and accessories to help move those tools around your work area. Here are a few items...

Read more...

Streamlight Donates $75,000 To The Breast Cancer Research Foundation

Streamlight Inc. recently contributed more than $75,000 to The Breast Cancer Research Foundation (BCRF), a not-for-profit organization with a mission to achieve prevention of and a cure for breast cancer. Since 2010, Streamlight has donated $525,000 to...

Read more...

AVI Announces New Live Stream 8 (LS-8) Webcast Event

On Wednesday, Oct. 8, 2014, at 6 p.m. analytical expert Ron Bilyeu will be teaching a free live, online course called “Computer Engine Data – Make Testing Quicker.”   In this webcast, Ron Bilyeu will take online attendees through the...

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 

Latest articles from our other sites:

Centric Parts Opens Friction Lab To Enhance Research And Development Program

Centric Parts has opened a new state-of-the-art friction materials lab at the company’s Compton, Calif., facility. The new lab expands the company’s engineering department and features a LINK Chase...More

Earn Rewards And YouTube Fame With Dorman's New TECH TUBE Installation Video Program

Have you always wanted to share your automotive installation tips on YouTube? Can professional technicians and DIYers benefit from your approach to certain repairs? A new installation video incentive program...More

Inside Import Car Collision Warning, Automatic Braking Systems

Anything that moves under its own power also has to stop, so brakes have been a safety feature on cars since day one. Over the years, technical innovations such as antilock brakes (ABS) have ­improved...More

Hyundai: Power Steering Oil Pump Whine

Before replacing a power steering oil pump for a whine noise condition, check the oil pump reservoir filter screen for contamination. If the filter screen at the bottom of the oil pump reservoir is clogged,...More

Domestic TPMS Guide

Chrysler TPMS Chrysler uses a Schrader Electronics or VDO TPMS system on just about every late-model vehicle. Chrysler has never used a band sensor in any of its platforms. On some 2004 and 2005 models,...More

Using Recalls, TSBs as Brake Job Tools

You are getting ready to perform a brake job on a vehicle. While checking the torque specifications on the vehicle, you decide to hit the tab with TSBs and recalls. All of a sudden you are staring...More

Chicago Pneumatic’s Offers New Range of Cordless Tools

Chicago Pneumatic is launching innovative new high-power cordless tools that deliver the power and performance of an air tool while providing the mobility of a battery tool. The new impact wrenches, impact...More

Snap-on Adds Free VERUS PRO Training Solutions Modules To Website

Snap-on has added free VERUS PRO Training Solutions videos to its website at http://diagnostics.snapon.com/trainingsolutions. The 10 modules are designed to help navigate the features and functionality...More