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. Show 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. 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 Rough/No Starts Symptom/Condition Diagnosis 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 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 Installation Source: ALLDATA Fuel Filter
Service on 4.0L Engine Removal Installation 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 How do I know if my fuel pump is bad on my Jeep Grand Cherokee?Signs of such failure are a car that won't start or stalls once it has started. Other times, the fuel flow can slowly become starved causing the check engine light to come on. Or if you hear a whirring sound coming from your fuel tank, the fuel pump may be about to fail, since fuel pumps do not normally make noise.
How do I know if my fuel pump is dying?Seven Signs Your Fuel Pump Is Going Out. Sputtering Engine. Your fuel pump is telling you something if your engine starts to sputter once you've hit the top speed on the highway. ... . Overheating Engine. ... . Low Fuel Pressure. ... . Power Loss. ... . Surging Engine. ... . Gas Mileage Decrease. ... . Dead Engine.. What are common problems with 2000 Jeep Grand Cherokee?Top 2000 Jeep Grand Cherokee Problems. Temperature Blend/Recirculation Doors May Fail and Cause AC Problems. ... . Engine Will not Start Due to Wireless Control Module Fault. ... . The Fuel Tank is Hard to Fill and/or the Fuel Fill Nozzle Shuts Off Repeatedly While Fueling. ... . Power Window Motor May Fail Due to Regulator Assembly.. How do you troubleshoot a fuel pump?Listen for the fuel pump: Put your ear near the fuel tank and have an assistant turn the ignition key to the “on” position. The fuel pump should make an audible noise if it's working properly. Whack the fuel tank: Have an assistant crank the engine while you hit the fuel tank with a rubber mallet.
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