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Ground to fuel injectors - 1991 Ford Mustang

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The ground is controled by the computer . u have and ignition control module fault . it is located on the side on the distibutor take less then 10 minute to replace and is always the problem i worked for ford for the last 24 years

Posted on Jan 16, 2013

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Feul injectors not pulsating

The voltage for fuel injectors go hot with the key on. The computer switches the ground on and off, check voltage and ground.
If the computer doesn't ground the fuel injectors, you'll have voltage on both legs.
If computer doesn't see rpm signal, it won't ground the fuel injectors. If no rpm signal check the crank sensor and ignition module, plus wiring circuits. Don't replace anything unless your testing points in that direction.

Jan 05, 2016 | 1994 Buick LeSabre

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Fuel injector just quite working

What is year--make--model? Check for voltage and ground at fuel injector. Check fuel pressure.

Dec 26, 2014 | Cars & Trucks

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04 400ex has lots of spark cpmpression and fuel timing is correct i dont no wat else to do

Did you check fuel pressure with a gauge? Autozone, some others, rent or loan fuel pressure gauges. If fuel pressure is good, check injector circuit. Each injector has two wires-power and ground. With key on- engine off, each injector should have battery voltage on the power wire (each power wire would be same color to all injectors)-use a test light or voltmeter to check for power.

If injectors have power to them with key on, post back and I can tell you how to check injector ground circuit with a test light. .... well here, you clip the test light lead on the POSITIVE battery post, and stick tester probe into the ground side terminal of injector connector. Now have someone crank the engine over: if ground circuit is good, the test light should be blinking. If both tests work, power and ground circuit, then injector circuit is good and they should be pulsing to spray fuel into the cylinders. Let me know what you find.

Jun 08, 2014 | Cars & Trucks

1 Answer

96 chev. Caprice won't start. Fuel coming up to fuel rack, but not injectors. Wat should I do?

There should be an injector fuse. Each injector has two wires to it-a power wire and a ground wire. The power wire should be hot anytime the key is on. Check for voltage with a test light. Usually the power wire is the same color to all injectors, while the ground wire for each is a different color from any others.

To check fully the injector circuit, purchase a cheap "noid light" at a parts store. You hook up the noid light into an injector connector. You can start the car or just crank it over. When the engine is running or cranking, the noid light should be blinking. If it blinks, the injector circuit is working for that injector. If it doesn't even light up, it could be the power side or the ground side. (The ground wire runs into the computer for controlling pulse by internally grounding the circuit for a split second.) If the light stays on steady, the computer is faulty-the internal injector ground is staying on, practically unheard of.
If the injector circuit is good, check fuel pressure-very critical on chevys that starting fuel pressure is correct. If all good, check for spark.

May 03, 2014 | Cars & Trucks

2 Answers

1988 Chevrolet k1500 350 v8 not getting signal to fuel injectors

So, it's the injector circuit. There is a 10 amp injector fuse in the fuse block, on left side, 4th one down. Check this fuse. It supplies constant power to both injectors, on the red wire to injector 1, and a white wire splice from this to injector 2. A steady 12 volts anytime key is in on, run, or start. You can check this with a test light or voltmeter. Ground the test light and probe injector connector's red wire on injector 1, and the white wire on injector 2-both should be hot with key on.
This may be why the noid light didn't blink. The noid light must have this steady power signal, and when the computer internally grounds the injector ground circuit for a split second, you get injector pulse-or a blinking noid light.
You can check the ground circuit separately with a test light also for each injector. Place the ground clip of test light on the POSITIVE battery post, and probe the blue (ground) wire on injector 1, the engine must be cranking over, and the test light should be blinking. Do the same for the green wire on injector 2. If the test light is blinking on both ground wires, with engine cranking-the ground circuit is good. You are sending power down the ground wire to computer, and when the computer grounds the circuit, the tester will light up-it will blink because the computer only momentarily grounds the circuit to cause pulsing of the injectors.

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1 Answer

Fuel injectors not spray

Are you sure it's not the fuel pump? I would be checking fuel pressure-the injectors need fuel under high pressure against them so they will spray out when pulsed.
What year is your Isuzu, and what size engine? Multiport injection has a higher pressure requirement than throttle body injection.
There should be a fuse for the injectors, check that. With key on, not start, the injectors would have power to them on the "injector drive circuit". In other words, constant power is supplied to the injectors when the key is on. The other wire at an injector is the ground wire. The ground wire goes into the engine computer. When the computer internally grounds the injector wire for a split second, the injector is energized and fuel is able to spray out.
Post back if you need help checking the injector circuit-both the power side and the ground side. You can check both with a test light.

Well, here it is anyway: ground a test light and probe the injector connector. With key on, one terminal should be hot-the drive circuit. Now move the test light lead to the POSITIVE battery post, and stick the test light probe into the injector terminal that did not light the test light-the ground terminal. Now have someone crank the engine over. If ground circuit is working, the test light should be blinking-meaning the computer is properly grounding the injector circuit. If both tests are good-a steady light on the power side (key on) and a blinking light on the ground side (engine cranking), the injector circuit is good.

Jan 28, 2014 | Isuzu Cars & Trucks

1 Answer

I have replaced the fuel pump on my 1991 chevy cheyenne im getting fuel to the injectors but they aint working

Check the injector fuse. With key on, injectors should have constant power available to them on one wire. The other injector wire is ground wire. With constant power to injectors, all it takes to pulse the injectors is for the computer to ground the injector ground inside the computer for a split second, and pulse occurs, causing fuel to spray out the injectors.
So if injectors aren't working, either the injector drive circuit (the power to injectors) or the injector ground circuit is lost. You can buy a cheap "noid light" at any auto parts store, and check the injector circuit. Just plug the light into the injector connector and crank the engine over. If the light is blinking, circuit is good. If no light, the circuit has a problem, either on the drive side or the ground side.
Here's a way to check the ground circuit separately. Use a test light clipped to the Positive battery post. Probe the ground wire terminal of the injector connector while the engine is cranked over. The test light should be blinking-meaning the computer is grounding the circuit normally and would be causing the injectors to pulse, if power is available to them.

Aug 19, 2013 | Cars & Trucks

1 Answer

Changed the fuel pump and filter...still won't start

Check the injector circuit. There should be a fuse for the injectors. Each injector has a power wire and a ground wire. The power wire should show current when key is on.
Your fuel pressure should show around 50 psi with key on. Is it?
How to check the injector ground circuit: Use a test light. Clip the lead of the test light to the positive battery post, and use the probe into the ground terminal of an injector connector (the connector is unplugged). Now observe the test light while someone cranks the car. If injector ground circuit is working right, the test light will be blinking-meaning the computer is correctly grounding the injector circuit for a split-second each time the light blinks. If no light, check ground wire from injector to computer. If light does not blink but is steady, computer failure.

Apr 05, 2013 | 2004 Pontiac Grand Am

4 Answers

Fuel injectors wont open malibu 2004 clasic

Hello! Please tell me what you meant by "We took the wires to check for mass"?

However, you are correct, it is fuse #5 10amp. It is located in the under hood fuse block. Change the fuse; If it does not hold perform the following test...

With key off...Disconnect the Injector's plug in connectors...Each connector has two wires marked A and B...A goes to battery feed and B to the Power Train Control Module (PCM)...

Using an ohm meter set on the X10 scale measure from each plugs pin A to ground...It must be open, no needle deflection...If you read any resistance at all, the hot lead which is common to all injectors, is grounded in the harness...

Next measure from each injector (both pins) to ground...You should read zero ohms,,,No resistance to ground...If any one injector reads to ground it is defective...Replace...Since all injectors are tied to common battery, any one injector shorted to ground will short all of them to ground...

Send a comment ..............saailer

Jan 23, 2010 | 2004 Chevrolet Malibu

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