How to Test the Fuel Pump on GM TBI Fuel Systems Updated: March 30, 2015 Written by: Abraham Torres-Arredondo As you're already aware, the throttle body fuel injection system on your 1987 to 1995 4.3L, 5.0L, or 5.7L pickup (or SUV) uses a low pressure (12 PSI) electric fuel pump located in the gas tank. 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). In this tutorial I'm going to show you two different methods to verify if the no start condition on your 4.3L, 5.0L, or 5.7L throttle body fuel injection (TBI) GM vehicle is due to a lack of fuel... which usually means that the fuel pump has gone BAD. One method involves using just starting fluid and the other involves using a fuel pressure gauge. One method is a very accurate way of diagnosing a lack of fuel condition causing a no start... the other method is not that accurate.

Here are the contents of this article at a quick glance: IMPORTANT: Gasoline is extremely flammable. Be careful and take all necessary safety precautions. Use extreme care when using starting fluid since it ignites as easily as gasoline. Accomplishing both tests indicated in this article, without any unhappy consequences, is more than possible if you're careful and use common sense. NOTE: This tutorial covers only the TBI equipped 4.3L, 5.0L, and 5.7L pickups (SUVs). If you need to test the ‘spider’ equipped GM pickups or SUVs... the following tutorial will help: A bad fuel pump will make your 4.3L, 5.0L, or 5.7L throttle body fuel injected pickup or SUV crank but not start. Here are some more specific symptoms: Although the above list is a not a very complete list of symptoms... the theme that runs thru' them, and any other related symptom, is that the engine will crank and crank, but not start. The first step is to see if a ‘no fuel’ condition is actually the cause behind your pickup or SUV's no start problem.

And the fastest/easiest way to do this is to see if the fuel injectors are spraying fuel while a helper is cranking the engine. If the injectors are not spraying fuel, then the next step is to coax the engine into starting using starting fluid. CAUTION: You'll be working around a cranking engine, so take all necessary safety precautions and think safety all of the time. OK, to get this show on the road, this is what you'll need to do: 1Remove the top cover of the air filter assembly.. You don't have to completely remove the assembly, just the cover. 2Spray starting fluid down the bore of the throttle body. When you have sprayed a good squirt of starting fluid, quickly place the air filter assembly's cover back on. IMPORTANT: Placing the cover back on the air filter assembly is important because it'll prevent any back-fire, that may occur, from spouting flames out of the throttle body. 3Have your helper crank the engine once the intake cover is back on the air filter assembly.

4You'll get one of two results with this test:Puppies For Sale Near Lawton Ok 1.) The engine will start momentarily and after a few seconds will die or.Siberian Cat For Sale Gold Coast 2.) The engine will only crank but not start at all.Ozone Air Purifier For Rent OK, let's find out what your results mean: If the engine started and ran for a few seconds: This means that the reason your pick up (or SUV) is not starting is due to a lack of fuel. Now that you have confirmed that the ‘no start’ problem is due to a lack of fuel, you now need to actually confirm how much pressure the fuel pump is producing with a fuel pressure gauge. For this test go to: TEST 2: Fuel Pressure Test with Gauge. The engine did not start, not even momentarily: This usually means that a lack of fuel IS NOT the reason your car is not starting.

Now, remember what I said about this test not being very accurate? Well, I suggest you do one more test...This is to remove the fuel line that connects to the fuel injector rail and place it in a container. Then have a helper bump the starter while you check to see if fuel comes out of the Line and into the container. This way, you can visually see if there is or there isn't fuel coming out of the fuel line. Quite a few things can cause a ‘no start’ condition and if you have ruled out the fuel pump as the problem... this tutorial may be of help: How to Troubleshoot a No Start (GM 4.3L, 5.0L, 5.7L).Can a 2" spacer be stacked on another 2" spacer? Can a 2" spacer be stacked on another 2" spacer? Is the total rise of the air cleaner the same as the spacer height? Will this work with the R2C 4412 air filter base part # 59210519? is this spacer made from steel or plastic Will this spacer work on a Edelbrock 600 cfm WHAT IS THE DIAMETER OF THIS 'Speedway Sure Seal O-Ring'

will this work with the Full Fin Dual Quad Air Cleaner Straight base pt no 2474450. I want to use two on a air gap dual quad on a zz4. Will this spacer clear the choke linkage on a 600 cfm quick fuel carburetor? Do you make a flat base air cleaner to go with this spacer? The base offered has a 1 1/2" drop so you would need a 2 inch spacer to gain anything. I want a flat base spacer that will fit in the 2 in spacer i already bought so the filter will stick up through the hood of my car I have an edelbrock carb with a 5 1/8" opening and want to use my original air cleaner with a 4 7/32" opening. Do you have an adaptor that will work? Long about 1991, pretty much all Jeeps came directly from the factory with fuel injection installed on their engines. This change was for good reason. The later years of carbureted Jeeps are a horrible mixture of old-school fuel delivery technology plugged up with some rudimentary computer controls that in theory should have made these Jeeps run cleaner and better.

Its not, and they don’t run nearly as well as Jeeps with fuel injection. These computer-controlled carburetors are known for their lack of reliability and generally have a negative reputation now that 20 to 25 years or so have passed. Other earlier carburetors are simpler, and while most are more than adequate for on-road use, not all do well in the hills. Some work pretty well off-road if they are tuned properly from the get-go, but this is the exception rather than the rule. The fact is you’ve probably heard someone recommend fuel injection as a cure for any and all carbureted Jeeps. In order to get a Jeep with a carburetor to run well off-road takes more than just having the physical parts. You need to know how to tune that carb for off-road use, or have access to someone who knows how to tune it. Fuel injection allows for a much more plug-and-play situation where the fuel and air mixture going into your engine is controlled by a computer that knows what it is doing (computer-controlled carburetors are much less forgiving).

A good fuel-injection system can compensate for altitude as well as other driving conditions. Also, fuel injection generally works much better off-road than some properly tuned carburetors and is much more robust with regard to changes in weather, altitude, and wear-and-tear. So what does one do to get fuel injection on a Jeep if all it currently has is a lowly carburetor? Well, one of the most common routes is to adapt a relatively simple, mass-produced, factory-available fuel-injection system in place of an old cranky carburetor. The name Howell Engine Developments is practically synonymous with Jeeps and reliable fuel injection conversions. For years this company has offered several different fuel-injection systems for Jeeps. Some of these systems use a GM-based throttle-body injection system. It just so happens that the GM TBI system for a GM 4.3L V-6 can be adapted to fuel an AMC 258 I-6 or Buick even-fire V-6. Also the GM TBI for 305ci V-8s and 350ci V-8s can easily be adapted to an AMC 304ci V-8, AMC 360ci V-8, or AMC 401ci V-8.