What should fuel pressure be on GM 4.3L Vortec?

You can find this tutorial in Spanish here: Cómo Probar La Bomba de Combustible (GM 4.3L, 5.0L, 5.7L) (at: autotecnico-online.com ). The fuel system in your 4.3L, 5.0L, or 5.7L Vortec engine needs at least 50 PSI of fuel pressure to start.

Why is my Chevy Vortec 4300 V6 leaking fuel?

In the L35 and LF6 engines, the spider injectors are known to leak at the pressure regulator and at the supply and return lines due to a design fault. Outside of leaking fuel onto the exterior of the engine itself, it can cause excess fuel to get sucked into the engine.

Are there any problems with the Chevy 4.3 Vortec engine?

The 4.3 Vortec engines made from 1996-2002 (L35 and LF6) have been reported to have engine knock problems. In a properly functioning engine, fuel burns in even pockets instead of all at once. The pockets burn in even timing, in sync with engine cycles. Engine knock occurs when the fuel burns unevenly and out of sync with the engine cycles.

How to check no fuel condition on GM 4.3L?

I’ve also included how to check a no fuel condition with starting fluid (although this is not the most effective way to test the fuel pump). It’s been my experience that misdiagnosing a bad fuel pump is a common occurrence on the 4.3L, 5.0L, 5.7L GM vehicles with the ‘Spider’ fuel injector assembly.

When to check fuel pressure with engine running?

Check the pressure as soon as you turn the key to run. It may drop a little as soon as the pump shuts off. With return-style fuel systems the pressure will be 8-10 psi lower when it is running depending on your engine vacuum.

What should the fuel pressure be on a CPI?

The CPI system’s fuel pressure should be between 60-66 PSI. The manual doesn’t specify if this pressure is key on engine off, only that this pressure should be maintained ‘ under all operating conditions’.

How much psi does a fuel pump need to start?

The fuel pump produces much more than just 50 PSI of course.. but the bare minimum the engine needs to start is 50 PSI… so anything less and it will crank for ever before it starts or not start at all.

What should the fuel pressure be on a Chevy Silverado?

If you want to save some bucks on this purchase take a look at my recommendations here: Where To Buy A Fuel Pressure Test Gauge. FUEL PRESSURE SPECIFICATION: The fuel pressure specification for the 1999-2006 4.8L, 5.3L, 6.0L Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL) is 55 to 62 PSI. Flex fuel engines: 48-54 PSI.

What was the minimum fuel pressure for a GMC Caballero?

The minimum flow was 29 gallons per hour and 12 volts was the minimum current requirement. The fuel pump was located in the gas tank. The GMC Caballero used a six-cylinder 4.3-liter engine from 1986 to 1987. This engine’s fuel pump required 12 pounds of fuel pressure per square inch.

What does 0 psi fuel pressure test mean?

CASE 2: You got 0 psi fuel pressure. This test result lets you know that the fuel pump is defective and is causing the engine to not start. Before you replace the fuel pump, make sure that the fuel pump relay and fuel pump fuse are supplying power to the fuel pump when the engine is being cranked.

What is the minimum fuel pressure for a GMC S15?

Fuel pressure specifications may vary from one vehicle to the next due to the difference in engine specifications. From 1985 to 1990 the GMC S15 used a four-cylinder 2.5-liter engine. This engine required 12 lbs of fuel pressure per square inch. The minimum flow was 29 gallons per hour and the minimum current was 12 volts.

Why does my 1994 Chevy S-10 not start?

1994 Chevrolet S-10 4.3 tbi. I never get the signal to turn on the fuel pump or fire the injectors but if i poor gas in the intake once the truck starts it runs fine. Any ideas ? I have replaced the fuel pump relay oil pressure switch and computer.

Where is the Schrader valve on the fuel rail?

The photo above shows the Schrader valve location on the fuel rail where you’ll connect your fuel pressure gauge to. Alright, here are the steps: Connect your fuel pressure gauge to the Schrader valve (see photo above).

What does 0 psi mean on fuel gauge?

CASE 2: The fuel pressure gauge’s needle DID drop down to 0 PSI immediately after the Key was turned to the Off position: This tells you that there is something leaking inside the plenum. More than likely, it’ll be the fuel pressure regulator, to make sure go to: TEST 2.

What should the fuel pressure be on a 4.3L Vortec?

The fuel system in your 4.3L, 5.0L, or 5.7L Vortec engine needs at least 50 PSI of fuel pressure to start. The fuel pump produces much more than just 50 PSI of course.. but the bare minimum the engine needs to start is 50 PSI…

What should the fuel pump pressure be to start the engine?

The fuel pump produces much more than just 50 PSI of course but the bare minimum the engine needs to start is 50 PSI. Anything less and it will crank for ever before it starts or not start at all. So, the very first thing you need to do is to verify that the fuel pump is delivering at least 50 PSI of fuel pressure while the engine is cranking.

What’s the fuel pressure on a 99 5.7L?

Not sure what this means in real life. My 99 5.7L was always a little below the low end of the fuel pressure specs – even with a new GM pump (still ran fine). Thanks for your reply. Key on, engine off for my truck is 55 psi. Driving is 45 psi. I just can’t believe 45 is enough for this engine.

What is the correct fuel pressure, 5.3 engine?

My 99 5.7L was always a little below the low end of the fuel pressure specs – even with a new GM pump (still ran fine). Thanks for your reply. Key on, engine off for my truck is 55 psi. Driving is 45 psi. I just can’t believe 45 is enough for this engine.

What to do if there is no pressure on the fuel pump?

If no pressure is present recheck the hose or adapter connection to avoid any false negatives, re-cycle the ignition switch to recheck. Still no pressure? suspect a bad fuel pump, fuel pump relay or fuse. Now start the engine so we can test the performance of the pump.

What happens if your GMC Envoy has low oil pressure?

One of the most serious issues that can happen to your GMC Envoy ‘s engine is if ends up with low oil pressure. Low oil pressure will cause the engine to seize up. When the oil pressure light on, it should be assumed that the engine locking up is imminent. We advise not running the engine until the issue can be properly diagnosed.

What causes low fuel pressure in an engine?

1 Clogged Fuel Filter The fuel filter cleans the fuel entering the engine. 2 Bad Fuel Pump A bad fuel pump is probably the most common cause of low fuel pressure. 3 Bad Fuel Pressure Regulator The fuel pressure regulator controls the fuel pressure in the fuel rail.

What should the fuel pressure be on a GMC Sierra?

Drives:2004 GMC Sierra Posted October 8, 2010 When the ignition switch is ON and the fuel pump is running, the fuel pressure indicated by the fuel pressure gauge should read 379-427 kPa (55-62 ps i). The spring pressure inside the fuel pressure regulator controls the fuel pressure.

Is the fuel trim on my Sierra out of Spec?

So I’ve been trying to learn more about my truck (07 sierra 5.3l NNBS 68K miles) and how to use my scan tool ( ELM327 wifi scanner with iOBD2 App). I was looking through the stuff I can read and saw fuel trim and it seems mine is out of spec.

How much horsepower does a 60 psi fuel pump have?

Now lets assume that your engine requires 60 psi and your fuel pump will be supplied with 13.5 volts. As you look at the chart you can see that at 60 psi and 13.5 volts this pump will flow at 63 gph. Using the 10 hp per gallon rule we can assume that this pump will support up to 630 hp (63 x 10 = 630).

What kind of fuel pump do I need for a LS engine?

Choosing the right fuel pump for your LS engine install or EFI conversion. One of the most common requests that we have come in is what electric fuel pump should be used in order to install an LS engine or to do an EFI swap.

What are the fuel pressure plugs on a 1996 Vortec?

Last night we replaced the plugs (he was running E3s after i told him to put delcos in some people Lol) and we had 2 fouled plugs.

What was the fuel pump voltage in 1993?

1993 Fuel Pump Circuit Tests (GM 4.3L, 5.0L, 5.7L). 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.

Can a GMC fuel pressure regulator go bad?

Then it will start. It runs/drives fine. I had a 98 Camaro RS with the 3.8 V6, and it had very similar symptoms (fuel pressure regulator was bad/going bad), but I was just wanting to make sure. Also, if I’m not mistaken the FPR is internal on my GMC, Right?

How to test a fuel pressure regulator ( FPR )?

Testing for Maximum Pressure The easiest way to test an FPR is with the use of a fuel pressure gauge. But first, you’ll start your tests with a quick preliminary check: 1. Open the hood and locate the fuel pressure regulator on one end of the fuel rail. This rail holds the fuel injectors in place.

Where is the fuel pressure regulator in the tank?

Any help is greatly appreciated, and thanks ahead of time. Your regulator should be in your bucket in the tank. If you end up replacing it may wanto look at the fuel pump too . if that needs replaced you might as well upgrade it to the walbro 225 bout the same cost easy to do and will have fuel pressure

How to check fuel pressure while cranking engine?

TEST 1: Checking The Fuel Pressure Specification. So, the very first thing you need to do is to verify that the fuel pump is delivering at least 50 PSI of fuel pressure while the engine is cranking. Yes… while the engine is cranking. Locate the Schrader valve on the fuel line that connects to the ‘Spider’ assembly.

How to check for fuel leaks in a GM 4.3L?

Once the fuel pressure gauge registers pressure, check for fuel leaks around the Schrader valve. It’s very important that NO fuel leaks are present for the accuracy of the test. Once you have verified no fuel leaks, continue to the next step. Have your assistant crank the engine as you eyeball the fuel pressure gauge.

How to do a GM fuel pressure test?

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What should the fuel pressure be on a GM 4.3L?

This is where you’ll connect your fuel pressure gauge (the first photo, in the image viewer, is of a 4.3L, and the second of the V8 engine). NOTE: In case you’re wondering, the factory manual specifies that the fuel pressure for the CSFI system should be between 56-62 PSI. The CPI system’s fuel pressure should be between 60-66 PSI.

What to do if your Vortec won’t start?

96 Chevy C1500 5.7L Vortec Truck won’t start, Replaced Fuel Pump, Filter & Has Spark. Hey everyone, I have a 1996 Chevy C1500 with a 5.7L Vortec, I got the truck recently and was told it just needed a Fuel pump, I replaced the Fuel pump, and the Filter, also the pump turns on and there is fuel up at the rail, I pushed the pin and it shot right out.

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 pump does a Chevy Silverado need?

It turned out the pump I put in was for a 96 C1500, which has a throttle body system and the pump only produced 20-30psi. The Fuel injection in the Silverado needs 55-65psi. Be very careful you didn’t put the wrong fuel pump in!!

What are the most common problems with a GMC Sierra?

Another 258 people reported the second-biggest issue where heating and air conditioning temperature and air delivery mode door actuators may fail. If one or more delivery mode door actuators fail, the HVAC system may not produce correct temperatures or air delivery. The HVAC system stores fault codes, which help with diagnosis.

What’s the difference between CPI and CSFI fuel injection?

If you don’t know whether you have a CPI or CSFI system, you can find out the difference between them by checking out the info in this subheading: ‘Spider Fuel Injection Basics’ found in this tutorial: How To Test The ‘Spider’ Fuel Injector Assembly (4.3L, 5.0L, 5.7L). Connect your fuel pressure gauge to the Schrader valve.

When did Vortec start using CSFI fuel injection?

The system was used on 4.3L V6 Vortec engines through 1995, and was redesigned in 1996 and renamed “Central Sequential Fuel Injection” (CSFI). The system was also added to 5.0L and 5.7L Vortec V8 engines.

What kind of fuel injection does a GM Vortec use?

Vortec 4.3L 5.0L and 5.7L engines from 1996-2002 have been found to be very sensitive to fuel deposits in the fuel injectors. The Vortec Central Sequential Fuel Injection system utilizes a unique fuel injector for each cylinder.

Can a GM Vortec be converted to MPFI?

The Auto Shop’s Vortec MPFI conversion eliminates the poppet nozzles, instead placing the injectors at the end of the tubes as shown below. This system fits under your stock upper intake with no visual changes when fully assembled.

What happens when the fuel pressure gauge drops to 0?

You’ll see one of two results: The fuel pressure gauge’s needle will drop 5 PSI only and remain steady for at least one full minute. Or the fuel pressure gauge’s needle will immediately drop to 0 PSI. If the fuel pressure drops down to 0 PSI within seconds, then you’ve got a problem.

What should I do if my fuel gauge is leaking?

If the gauge is leaking, you’ll need to tighten it some more and recheck. Now that you have verified that the fuel pressure gauge is not leaking, crank the engine. If the engine starts, have him (or her) turn it off. Observe the fuel pressure gauge’s needle, as soon as you turn off the engine.

What should the fuel pressure be on a GM 93 Blazer?

This is the procedure for checking for an internal fuel leak on your 1st gen GM 4.3V6 with the CPI engine in it. This is my 93 Blazer in the test. Fuel Pressure should be 58-62 psi, and it should hold that pressure, and hold it when turned off as well. I have a leak inside my upper intake as I show you in the video.

How do you install a fuel pressure gauge?

Alright, here are the steps: Connect your fuel pressure gauge to the Schrader valve (see photo above). Before you do, place rags under and around the Schrader valve (as a safety precaution, since fuel will leak when you install the fuel pressure gauge). Activate the fuel pump to pressurize the line.

What should fuel pressure be on GM 4.3L Vortec?