Testing TBI Injectors You can visually inspect the fuel spray on TBI system injectors. Fuel flow spray is readily accessible, making it fast to check for potential problems. Checking Fuel Spray Remove the cover off the air cleaner housing (where the air filter lives). Ask an assistant to start (or crank the engine, if it doesn't start).
How do I know if my TBI injectors are bad?
Testing TBI Injectors. You can visually inspect the fuel spray on TBI system injectors. Fuel flow spray is readily accessible, making it fast to check for potential problems. Checking Fuel Spray. Remove the cover off the air cleaner housing (where the air filter lives).
How do you test a fuel injector?
1 First, hook the test-light clip to a bolt or bare metal bracket on the engine. 2 Unplug the electrical connector from the fuel injector you want to test. 3 Turn the ignition switch to the ON position. 4 Touch the terminals (one at a time) of the harness connector with the test light. ... More items...
How do you check the fuel spray on a TBI system?
You can visually inspect the fuel spray on TBI system injectors. Fuel flow spray is readily accessible, making it fast to check for potential problems. Checking Fuel Spray. Remove the cover off the air cleaner housing (where the air filter lives). Ask an assistant to start (or crank the engine, if it doesn't start).
What should the fuel pressure be on a TBI fuel injection system?
Fuel pressure should be a constant 10 – 15 PSI on a TBI fuel injection system and is typically around 12 – 13 psi. Higher pressure than 15 psi indicates that there is an issue with the installation. Many times this is due to kinked fuel lines, improper routing of the return line and/or fuel line restrictions.
How do you check for bad injectors?
0:281:44How to Test Fuel Injectors | DIY Car Repairs | The Home Depot - YouTubeYouTubeStart of suggested clipEnd of suggested clipPlace the metal tip of a long screwdriver up against each injector and place your head near theMorePlace the metal tip of a long screwdriver up against each injector and place your head near the screwdriver handle to listen.
How do I manually test my fuel injectors?
Keep the engine running and touch the end of a long metal screwdriver against the fuel injector. Put your ear on the opposite end of the screwdriver. A clicking sound means the injector's working. Silence means the injector may need to be cleaned or replaced.
What controls the injectors on a TBI?
The vehicle's fuel pump moves fuel from the gas tank to the throttle body assembly. Then a computer, often referred to as the powertrain control module (PCM), activates the TBI injectors. The injectors spray fuel into the throttle body bore, right above the throttle plates.
How do you check an injector with a multimeter?
0:523:21How to Check Fuel Injector Resistance with a MultimeterYouTubeStart of suggested clipEnd of suggested clipSo you're going to get your multimeter you're going to turn it on and you want to set it to ohms.MoreSo you're going to get your multimeter you're going to turn it on and you want to set it to ohms. Which is this horseshoe Omega sign and set it to 200. And when it's in 200.
What is the most common cause of injector failure?
Common causes of injector failure While many things can cause breakdowns, the most likely cause of premature failure is fuel contamination. Fuel contamination occurs when debris in the fuel gets past the filtration, destroying the sealing surfaces.
How do you clean fuel injectors without removing them?
0:422:33How to Clean Fuel Injectors in Your Car (Without Removal) - YouTubeYouTubeStart of suggested clipEnd of suggested clipIt just screws right onto the fuel injection rail at the test port then you go to the fuse box andMoreIt just screws right onto the fuel injection rail at the test port then you go to the fuse box and take out the fuel pump relay to turn the fuel pump off.
What causes injectors not to Pulse?
The nature of the cause of no injector pulse is that there is no power input. The three main factors that lead to that condition are blown injector fuse, bad injector electrical relay, and bad wiring. Typically, fuses and relays will be located in the junction box in the engine compartment.
What tells the injectors to fire?
Electronic Control Unit (ECU) The ECU is the brain of the operation. It uses engine RPM and signals from different sensors to meter the fuel. It does this by telling the fuel injectors when and how long to fire. The ECU often controls other functions like the fuel pump and ignition timing.
Does a TBI have a fuel pressure regulator?
Second only to the stock TBI ECM, the stock TBI fuel delivery system leaves a lot to be desired. Starting at the tank the fuel pump is a turbine pump. Quiet and long lasting, but weak fuel delivery. The fuel pressure regulator is set for approximately 12 psi (30 psi on '94 & '95 BBC trucks).
What voltage should be at injectors?
12 voltsMost injectors use 12 volts to energize the coil, and the driver energizes the circuit by pulling it to ground. When the injector is energized, the voltage drops to almost zero. If it does not, it could mean an open or weak connection in the wiring harness or open coils inside the injector.
How many ohms should a fuel injector read?
between 10 and 18 ohmsWith your vehicle off, disconnect the electrical connector for your fuel injector. Use a multimeter to take a resistance reading. Check your vehicle's service manual or online to learn the correct value (most fuel injectors should read between 10 and 18 ohms).
How do you check the voltage in a fuel injector?
Part 1 of 2: Testing injector resistanceMaterial Needed.Step 1: Make sure the key is off. ... Step 2: Remove injector wiring harness. ... Step 3: Set DVOM to measure ohms. ... Step 4: Test resistance with DVOM. ... Step 5: Repeat with all injectors. ... Step 1: Turn the car on. ... Step 2: Set up DVOM to measure DC voltage.More items...•
How do I test my fuel injectors with a battery?
4:577:459v Battery Fuel Injector Test!! Jeep Fuel Injectors - YouTubeYouTubeStart of suggested clipEnd of suggested clipThe system. And then once this is pressurized. Then I'm going to just tap real quick the batteryMoreThe system. And then once this is pressurized. Then I'm going to just tap real quick the battery here and we should get a little bit of fuel squirting out of our injector.
How many ohms should a fuel injector have?
With your vehicle off, disconnect the electrical connector for your fuel injector. Use a multimeter to take a resistance reading. Check your vehicle's service manual or online to learn the correct value (most fuel injectors should read between 10 and 18 ohms).
What happens when a fuel injector stuck open?
Stuck open fuel injectors mean less or no fuel for the engine. You will notice this from the frequent misfires in the engine and as the acceleration gets weaker. If you feel a pause after stepping on the gas, then that might be the fuel injector messing with your engine.
What can cause fuel injectors not to spray?
If it does not spray, the problem is the injector or no fuel pressure. The injector should have around 1.3 ohms of resistance, if it is open or zero resistance, it is bad. The injector could be totally clogged as well. Fuel pressure should be 9 to 13 psi.
How to test if an injector is dead?
How to Test a Dead Injector. One of the tests you can do on a dead injector is by checking the injector's coil. For this test, you'll need a multimeter and the resistance value for the coil inside the injector. You can look up the injector resistance value in the service manual for your particular vehicle make and model.
What does it mean when your injectors are negative?
If any of the previous tests came out negative, it doesn't necessarily mean you injectors are operating correctly. You tested for some common problems you can troubleshoot at home, but one or more injectors may have a worn or dirty (less common) valve, or a weak or broken return spring that's causing the injector to block or leak fuel. Some of these problems can be a challenge to diagnose without the right tools. But a repair auto shop with professional equipment can help you pinpoint these type of problems.
What does infinite resistance mean on a meter?
If your meter reads infinite resistance, it means the coil in the injector is opened.
What does it mean when your meter reads infinite resistance?
For example: If your meter reads infinite resistance, it means the coil in the injector is opened. If your reading is jumping all over the place, the coil is partially opened.
Why does my injector make a clicking sound?
When the injector opens and closes , you can hear a clicking sound. The sound comes from the solenoid inside the injector activating and deactivating the injector's valve. If you don't hear the clicking sound, either the solenoid has failed or the computer isn't sending the pulse signal. So you have a dead injector.
Why is my fuel injector misfired?
If you don't have a scanner, most auto parts store will get the codes for you. Usually, this is due to a bad spark plug wire, coil or fuel injector. If the misfire is reported on cylinder 1, for example, swap wires or coil with other cylinder and see if the misfire moves as well. You may need to test the injector.
Why is my test light not glowing?
If the test light doesn't glow, you've found the problem. Check the power side of the circuit for a short, blown fuse , or bad connection along the circuit, including the computer. Now, plug back the harness connector to the fuel injector and hook the test light clip to the positive side of the battery.
How to tell if injectors are leaking?
If you take a timing light and clamp it on the coil wire you can see if one of the injectors is leaking by running the engine and flashing the light at the gas coming from the injectors if one is leaking you will see drips.Also when you first shut it off watch for drips coming off the injectors.You may also have a bad pressure regulator.Do you have access to a pressure guage that will work on this truck?
What came with the ECM truck?
ECM & Prom came with the truck. Ran these in another Burb and it ran great.
Why are O/2 cross counting?
Davo's got you on the right track. The O/2's are cross counting because the ecm will compensate some of the excess fuel. What you need to look at is the Block learn and Integrater 128 is ideal. If it if constantly dropping from the time it is started and is below 128 then the computer is trying to overcome a rich situation. If it's holding around 128, then you don't have a rich problem. Check that they don't leak after shutdown and see if you still have a good spray pattern with the timing light.
What would happen if map was your problem?
if map was your problem, you'd have it in open or closed loop.
Is EGR clean?
EGR is clean and holds up with vacuum, solenoid is new.
Does the 89 TBI have a cam position sensor?
There are no crank or cam position sensors on the '89 5.7 TBI.
Does hooking to coil wire damage timing light?
Hooking to the coil wire will not damage your timing light.
Why does my engine misfire?
There are a number of issues that may cause a misfire in your engine. A faulty ignition coil could be failing to transmit power to the spark plugs that you replaced, but a fuel injector could also be the culprit.
Why is my fuel rail leaking?
This issue could be caused by a failing ECU, or one of the injectors along the fuel rail may be faulty.
Where are fuel injectors located?
Most applications have one fuel injector for each cylinder. They are usually located on the intake manifold and are connected to one another with a fuel rail.
Why is my fuel pump not holding pressure?
It could be that the fuel pump itself is not holding residual pressure when turned off. Listen for a "click" sound coming from the pump when you key the car on. You can also try cycling the key between off and run several times to allow the pump to prime the fuel lines.
How to protect yourself from car accidents?
Put on the appropriate safety gear. Before beginning any automotive project, you need to take steps to protect yourself from injury. Eye protection like safety glasses or goggles will keep debris from falling or spraying into your eyes while you work. Choose eye protection that fits comfortably and won't interfere with your vision. Gloves are an optional addition to the safety gear required for this task.
How many testimonials does wikihow have?
wikiHow marks an article as reader-approved once it receives enough positive feedback. This article received 12 testimonials and 100% of readers who voted found it helpful, earning it our reader-approved status.
Where is the fuel rail on a V8?
The fuel rail is a cylindrical rail that will run along the top of the intake manifold, and each fuel injector will be between the fuel rail and the intake manifold. V style engines (V6, V8, V10) will have two fuel rails with half of the injectors on each side of the motor.
How Much Fuel Pressure Does A TBI Need?
A fuel pressure regulator is set for 12 psi. However, 9 psi fuel pressure is adequate for a TBI.
What Happens When You Unplug Fuel Pressure Regulator?
Unless the regulator is leaking, the fuel pressure will rise, if you unplug the fuel pressure regulator.
Can A Car Run Without A Fuel Pressure Regulator?
No, a car won’t run, if it doesn’t have a fuel pressure regulator. If there is no fuel pressure regulator, the fuel will directly go to the car’s system. It won’t ever reach the injectors.
Why does my engine burn more fuel than usual?
As we discussed earlier, engines burn more fuel than usual when the fuel pressure regulator has gone bad. Too much fuel consumption can cause your engine to backfire. In addition, you may even notice your engine hesitating before reducing speed. 5.
How to tell if GM TBI fuel pressure regulator is bad?
Otherwise, your vehicle can be severely damaged. Here are 7 symptoms of a bad GM TBI fuel pressure regulator. 1. Bad Acceleration : An early sign of a bad GM TBI fuel pressure regulator is bad acceleration.
What causes spark plugs to turn black?
A faulty fuel pressure regulator can disable the fuel/air mix inside the combustion chamber. As a result, the spark plugs tips get covered in a black powdery substance.
What does it mean when your car has oil stain?
If you notice an oil stain under your car’s tailpipe, it can indicate a faulty fuel pressure regulator. This condition means your fuel pressure regulator got damaged or has leakage.
