How to test a GM 4.3L fuel pump?

More GM 4.3L, 5.0L, and 5.7L Tutorials. It’s very important that you start off your fuel pump relay diagnostic by first testing the fuel pump pressure with a fuel pressure test gauge. If the fuel pump relay IS NOT activating the fuel pump, the fuel pressure test gauge will register 0 PSI when cranking the engine.

What kind of fuel pump does a Chevy Tahoe have?

This tutorial will show you how to test the fuel pump relay on your 1997, 1998, 1999 Chevrolet/GMC full-size Pick Up, Suburban, Tahoe, or Yukon. It’ll also show you how to bench test the fuel pump relay in a step-by-step way to find out if it’s defective or not.

Why does fuel gauge read wrong after fuel pump replaced?

Fuel gauge reads wrong after fuel pump replaced – YouTube If you have a 96 or 97 year gm truck that needs a fuel pump, be sure to order it by the VIN. There is an option for a anti-slosh module that could cause you If you have a 96 or 97 year gm truck that needs a fuel pump, be sure to order it by the VIN.

What should fuel pressure be if fuel pump is not activating?

If the fuel pump relay IS NOT activating the fuel pump, the fuel pressure test gauge will register 0 PSI when cranking the engine. If the fuel pump relay is activating the fuel pump, then it’ll register about 56-62 PSI even if the engine does not start. Any fuel pressure below 50 PSI and the engine will NOT start.

Where is the fuel pump relay located on a car?

The fuel pump relay is an electronic component that is found on virtually all vehicles equipped with an internal combustion engine. It is often found in the fuse box located in the engine bay and functions as the primary electronic switch that controls power to the fuel pump. The fuel pump relay is usually controlled by…

How can I tell if my fuel pump relay is defective?

It’ll also show you how to bench test the fuel pump relay in a step-by-step way to find out if it’s defective or not. Contents of this tutorial: Before You Start Your Fuel Pump Relay Diagnostic. TEST 1: Swapping Out The Fuel Pump Relay. TEST 2: Making Sure The Fuel Pump Relay Has Power. TEST 3: Bypassing The Fuel Pump Relay.

How do you disable a fuel pump relay?

Step 6: Open the vehicle’s hood to disconnect your battery. Take the ground cable off of the battery’s negative post disabling the power to the fuel pump and sending unit. Step 7: Locate the fuse box in the engine compartment. Remove the cover to the fuse box.

Where are the fuel pump and AC relays located?

The AC relay is located in the same under-hood fuse/relay box the fuel pump relay is in (see illustration above). Locate the fuel pump and AC compressor relays in the under-hood fuse and relay box. Swap the relays .

Why does my engine light come on after replacing the fuel pump relay?

If your engine light comes on after replacing the fuel pump relay, then there may be further diagnosis of the fuel pump assembly needed or even a possible electrical issue within the fuel system.

How to test a GMC fuel pump relay?

TEST 1: Swapping Out The Fuel Pump Relay. TEST 2: Making Sure The Fuel Pump Relay Has Power. TEST 3: Bypassing The Fuel Pump Relay. TEST 4: Bench Testing The Fuel Pump Relay. Fuel Pump Circuit Diagram. Where To Buy The Fuel Pump Relay. More GM 4.3L, 5.0L, and 5.7L Tutorials.

What are the symptoms of a bad fuel pump?

Symptoms of a Bad Electric Fuel Pump Nearly every modern fuel-injected car and truck requires a fuel sending unit. The Fuel Pump for 1999 to 2003 Chevrolet and GMC Pickup Trucks takes the form of an electric pump mounted in the fuel tank, which you might be able to hear as a quiet whirring sound when the key is first turned.

Is there an electric fuel pump in a GMC pickup?

The Fuel Pump for 1999 to 2003 Chevrolet and GMC Pickup Trucks takes the form of an electric pump mounted in the fuel tank, which you might be able to hear as a quiet whirring sound when the key is first turned.

Can a bad fuel pump make a 4.9L start?

A bad fuel pump will make your 4.9L, 5.0L, or 5.8L multi-port fuel injected pickup (van or SUV) crank but not start. Here are some more specific symptoms: The ignition system is creating and delivering spark to the spark plugs.

Can you test the fuel pump on a GM Truck?

And although GM did not include a Schrader valve to which you could connect a fuel pressure gauge, it can be tested with one to find out if the fuel pump is producing the correct pressure (or not).

Symptoms Of A Bad Fuel Pump. Where To Buy The Fuel Pump And Save. TEST 1: Using Starting Fluid. TEST 2: Fuel Pressure Test With Gauge. Which And Where To Buy A Fuel Pressure Gauge. More GM 4.3L, 5.0L, 5.7L Tutorials. You can find this tutorial in Spanish here: Cómo Verificar La Bomba de Combustible en Los Sistemas TBI (at: autotecnico-online.com ).

How many volts does a fuel pump have?

Should have 10 to 12 Volts DC with Key On Engine Cranking or Key On Engine Running (KOER). This voltage comes from the GRY inline fusible link located in the engine compartment junction block. Should have 10 to 12 Volts DC when the engine is being cranked and relay has activated. Should have Ground all of the time.

How can I Fix my Chevy fuel pump?

Ask a Chevy Mechanic for Answers ASAP By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. My Chevy has no power to fuel pump. How can I fix it? no power to fuel pump… Submitted: 10 years ago. Category: Chevy

How can I tell if my fuel pump relay is faulty?

2. Engine does not start. Another symptom of a faulty fuel pump relay is an engine that does not start. If the fuel pump relay fails the fuel pump will be left without power. The engine may still crank when the key is turned, however it will not be able to start due to lack of fuel.

How can you tell if your Chevy Silverado fuel pump is going out?

The only way that you are going to know that your Silverado’s fuel pump is going out is that it is no longer providing enough fuel pressure to keep the engine running under a heavy load, or at high-speed. Typically, if you are heading up a hill (or accelerating) the engine may start to feel like it is just running out of steam.

Where is the power wire on a Chevy fuel pump?

Want to make sure its a 5.7L engine with the classic style truck and not the new style truck with the 6.0L Right? On the fuel pump connector, the gray wire is the power wire. The thick black wire is the ground.

Where is the connector on a Chevy fuel pump?

When you get the Delco replacement parts it comes with a new connector on the fuel pump side. The problem is the connector on the vehicle side of the harness. In the online Chevrolet repair manual I use, a Tech Tip states, the connector should be replaced with the fuel pump assembly.

Where do you find the fuel pump relay?

When you shut off the ignition, it powers down the fuel pump. In most vehicles, the fuel pump relay can often be found in the fuse box in the engine bay, which is usually a long black box which contains fuel pump relay along with various other fuses and relays.

What are the symptoms of a bad fuel pump relay?

A bad fuel pump relay can cause many different symptoms. Here are the most common ones The fuel pump relay is an important component of the fuel system of your vehicle. The fuel pump relay gives the fuel pump power when it is time to build up fuel pressure in the rail.

Is there an ECM signal to the fuel pump relay?

The fuel pump relay works as it should. I always have power to Pin 30. I believe the ECM tells the relay to work via the green/black wire to Pin 85. This should happen for 2 seconds when the key is turned on. I have tested this when the issue is occurring and have confirmed that no signal is being sent from the ECM.

How do you clean a fuel pump relay?

Since any debris will affect the fuel pump relay’s performance, you should regularly inspect and clean it when necessary. The fuel pump relay is an electrical car part, thus be extremely careful when handling a relay. First, take off the relay and use the blower to blow off dirt and dust for about 1-2 minutes.

What causes PCM to disable fuel injectors?

@jrt2020 , Josh, The anti-theft system (Pass Lock) failure will mimic this, as anti theft tells PCM to disable the fuel injectors.

Why does my GM 6.5 liter diesel engine not work?

The main cause of driveability problem is the PMD / FSD Module of the electronic fuel injection system that mounts on the injector pump, it is the most common part to fail on the GM 6.5 Liter Diesel Engines. Jim’s invention of the PDC/PMD Remote Package solved the PMD failure problem and is still offered here for sale today.

How to troubleshoot a GM fuel pump relay?

The following tutorial may be of help: Troubleshooting The Fuel Pump (GM 4.3L, 5.0L, 5.7L) (at: troubleshootmyvehicle.com ). The following links will help you comparison shop for the fuel pump relay:

Where is the Maxi injector on a Chevy truck?

The MAXI injector is mounted in the center of the intake manifold on the 4.3L engine, and is hidden inside the split plenum manifold. Instead of spraying fuel directly into the manifold like a throttle-body injector, the MAXI injector routes fuel into six nylon fuel lines that have poppet-style spray nozzles on the end.

How many fuel injectors are in a Chevy truck?

If one comes loose, it can spray fuel where fuel doesn’t belong and create a potential fire hazard. On the second generation Central Sequential Fuel Injection (CSFI) system (1996 and up), the MAXI injector in the central housing has been replaced with six individual injectors, each of which feeds fuel to its own poppet spray nozzle.

How to repair a GMC Vortec fuel injector?

1. Heat the hose like you did before. Heating only the very end will help you keep from kinking. 2. Slowly press the poppet back in, don’t rush it. 3. let it fully cool and give it a few good tugs to make sure it set.

What kind of fuel injection does a GMC use?

Back in 1992, General Motors introduced a new type of fuel injection system known as “Central Port Injection” (CPI), which GM also refers to as “Central Multi-point Fuel Injection” (CMFI). The system was used on 4.3L V6 Vortec engines through 1995, and was redesigned in 1996 and renamed “Central Sequential Fuel Injection” (CSFI).

How to test a GM 4.3L fuel pump?