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George H.
George H., ASE Certified Technician
Category: Car
Satisfied Customers: 18665
Experience:  ASE Master Tech 15+ yrs, AAS Automotive Technology, Factory trained Asian specialist
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I have replaced crankshaft sensor last month ,could this have..sparks

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I have replaced crankshaft sensor last month ,could this have failed yet again. I'am not getting any sparks at the plugs

Hello I will help you with your question,


If the sensor was from Hyundai and the connections are secure you will have to do some testing to determine if you have power and ground or if something else is going on with your ignition system.


Do you have a voltmeter?



Customer: replied 8 years ago.
Yes I do

OK the first thing is to be sure you have power and ground to the sensor and a signal (varying voltage from the sensor.


The wiring diagram is below




If you cannot read it use the connector diagram at the left and the diagram below to determine the pins to test




If you have power, ground and signal at the sensor check the ignition coil for power and ground there.




If you have pproblems reading the wire diagrams let me know, remember I don't know how much you know!!


I will help you determine the cause of this but it will take some testing so let me know what you find and we will get to the bottom of this



Customer: replied 8 years ago.
So I use Ohms or voltage for test? what should I be looking for

You should be looking for DC voltage. Disconnect the sensor connector and measure between the Pink and the black/ white stripe wire you should have a voltage shown there. Let me know what that is and what you measure at the battery. At the coil connector you should have battery voltage between the Pink/black wire and the black wire. All measurements are taken with the key on.


Let me know what you find



Customer: replied 8 years ago.

I got16.48 at battery and15.16 between pink and black on sensor wire


Customer: replied 8 years ago.

I got 16.48 at battery and15.16 between pink and black on sensor wire


OK we will have to start with the battery voltage,


Normal battery voltage is between 12.4 volts and maybe 13.1 volts with the engine off. Are you charging the battery now? If you are turn the charger off, turn the headlights on for thirty seconds, turn them off and wait two minutes. Then check the battery voltage.


Let me know if you know why you do not have the correct voltage.



Customer: replied 8 years ago.

Battery 14.11

Sensor 13.81

Coil 0.26

If you have no voltage to the coil you need to check the Ignition coil fuse in the underhood junction box as shown below at location #18 in the upper left fuse section




Let me know if the fuse has power on both test points with the key on


You are still high on battery voltage 12.6 would be normal





Customer: replied 8 years ago.
the fuse holder has power both sides of the pole

Double check the power to the coil, check from the pink/black wire to the black wire and to the engine to see if the ground is broken


If you have power to the fuse and no power at the coil you have to have a break between the two.


Let me know and I will try to find a harness diagram



Customer: replied 8 years ago.
Ok got power on all points just was not making proper cotact at coil

You will have to check to see if one of the injectors is being pulsed. Pick any one and use a pair of needles to probe from the back side of the connector while you are cranking the engine you should see a changing voltage while cranking.


What are you using to check for spark?



Customer: replied 8 years ago.
got a pulse i pulled the plug earlier and grounded it and turned the engine no spark

Get a spark checker to test with it is more reliable. You can do the same test with the coil to see if it is being pulsed as you did with the injectors. Test between the pink/black wire and any of the cylinder wires (refer to the diagram) The signal will be one half of the injector signal so it may be lower (depends on the meter)


Let me know if you have a pulse to the coil



Customer: replied 8 years ago.
I can try and get one in the morning

Try the test to see if there is pulse to the coil and let me know. The spark checker is for the future.



Customer: replied 8 years ago.
The engine just fired up breifly then died again ?
You may have a poor connection. Do you have a pulse to the coil all the time or does it come and go?
Customer: replied 8 years ago.
the engine is now stuggling to turn over as if the battery is dead and I'm also getting a shock as I get out of the car as well

What is the battery voltage, it may be falling low enough to cause the computer to shut down. Were you charging the battery before? Is the battery weak? If it is you will have to install a good battery as electronics will not operate with low voltage.



Customer: replied 8 years ago.
Voltage is still around 14 ?? the battery has been charging all day . It just changed after the engine briefly started

If your battery is still 14 volts after cranking there is something wrong with the meter or the setup. A battery will not have more than 12.6 volts unless there is a surface charge which would be used when you cranked the engine. You will have to limit the time you charge the battery unless it really needs to be charged.


The test for pulse at the coil will not be valid unless you have 10.5 volts at the battery while you are cranking the engine. This is without a charger!


Let me know the cranking voltage, the starting battery voltage (before cranking) and if you have enough voltage if the coil is being pulsed.



Customer: replied 8 years ago.
Might have to go and get another voltage tester it still reading high 14s same on my truck as well
If you have two readings the same you will need a different meter. The voltage measurement is critical to good diagnosis. I will be on most of the day tomorrow if you want to continue then.
Customer: replied 8 years ago.
Ok battery reads 12.7 similar reading at coil which then fluctuates when engine is cranked

Much better, If you have a pulsing voltage at the coil you should have spark if the coil is intact. As there are three coils in the coil pack it is not likely that all the coils have failed, not unheard of bu unlikely. You will need a good spark checker, the type that looks like a sparkplug wit a clip on the ground casing is a good choice or the screw adjustable type will work.


There are a couple of reasons that a pulsing voltage would not fire the coil (bad grounds) but generally if the voltage pulses at the coil you should have spark. I know you cannot get to the rear plugs easily but what is the condition of the front three plugs?



Customer: replied 8 years ago.
plugs got changed out last year slightly dark but its my wifes so it never really gets a good run.I have put on a inline ignition test on the plugs but not showing any spark

You likely are looking at a coil but I never have trusted an inline checker, If the ground pulse from the computer to the coil is not all the way to ground (bad ground at the computer or the coil) you can have a weak spark that will not show at the inline spark checker and in that case you would be replacing a good coil.


You might remove and replace the coil to ensure that the mounting surface (which is the ground) is clean. I have no reason to suspect the computer at this point.



Customer: replied 8 years ago.
is there any continuity check for the coil

You can try this test with your meter on the ohms scale but it is very hard to measure small resistances accuratly so it has to be way off to be a fail coil from this test




Measurement of the primary coil resistance
Measure the resistance between connector terminals 1 and 2 (the coils at the No.3 and No.6 cylinder sides) of the ignition coil, and between terminals 1 and 3 (the coils at the No.1 and No.4 cylinder sides), and between terminals 1 and 4 (the coils at the No.2 and No.5 cylinder sides)

Standard value: 0.74 ±10% (Ohms)




Measurement of the secondary coil resistance
Measure the resistance between the high-voltage terminal for the No. 3 and No. 6 cylinders, between the high-voltage terminals for the No.1 and No.4 cylinders and between the high-voltage terminals for the No.2 and No.5 cylinders.

Standard value: 13.3 ±15% (kOhms)

CAUTION: Be sure, when measuring the resistance of the secondary coil, to disconnect the connector of the ignition coil.


Let me know



Customer: replied 8 years ago.
Cyl1&4 11.76 Cyl 2&5 11.76 Cyl 3&6 11.79

Those are all within specs so the secondaries are OK What was the primary measurement? One tip, put the meter leads together with the meter set to its lowest setting (200?) (20?) and what ever reading you get with the leads together subtract from what you measure.



Customer: replied 8 years ago.
Ihave just did a test between the Crankshaft sensor and get no reading what so ever? I'm using an
Innova3320 voltmeter new one so I know its ok

If you are testing for resistance at the crank sensor you will not get a reading as this is a hall effect sensor, in fact the sensor can be damaged by applying voltage (resistance testing) to the sensor in reverse of what is applied when it is in the circuit.


The pulse you have seen in the injectors and the coil is due to the sensor input. This verifies the sensor is operating. If you have a pulse to the coil but no spark you have a bad coil unless the interuption of current flow only partial due to a poor ground such as the coil mounting surface or the ground for the computer.


You can test the coil output but it will take a spark checker. provide power to the coil by turning the key on, with a needle inserted in the back of one of the CYL wires attach a jumper to the needle and touch it to ground (clean metal) for the count of three, pull the jumper off of ground and the coil should spark. An inline spark checker is nor recommended for this test.



Customer: replied 8 years ago.
when you talk of a pulse do you mean voltage flutuations

Yes they are a result of the crank sensor input to the computer and the computer responds by pulsing the injectors and the ignition coil. The computer will also keep the fuel pump energized as long as it recieves crank pulses.



Customer: replied 8 years ago.
yes getting plenty of gas,I'll call it for tonite can carry on tomorrow as its dark out there now
OK I will be here tomorrow until 2 ET
Customer: replied 8 years ago.
ok thanks have a good evening

I see you put a coil on this along with MAF and lots of other items. You replaced the cat and it ran OK after that? No missing or other drivability issues?


I would concentrate on getting spark from this coil or check the old coil to see if it is OK.


Were you able to do the primary measurements in the first part of the test above? Can you compare the readings you get from the ol?d coil to the new one?


Let me know what you find



Customer: replied 8 years ago.
I don't have the original coil to compare with,could there be a problem with the ECM?

There could be a problem with the ECM but I haven't seen anything to indicate that yet.


If you have a good clean ground to the coil, power to the coil, and ground pulse from the ECM (all this you measured) you should get a golod spark out of the coil. Did you try to ground the Yellow/white, orange/black or red/black wires at the coil for three seconds and pull the jumper wire off ground to see if the coil produces spark?


Customer: replied 8 years ago.
Not tried this yet was not clear on how to do it

OK, turn the key on so there is power to the coil, leave the coil plugged in. On the back of the connector insert a needle in the yellow/white stripe wire alongside the wire connector so you don't pierce the wire but slide down alongside the contact. Put a spark checker on the #1 or #4 plug wire and run a jumper from the needle to a clean ground for three seconds, when you break contact with the ground the coil should fire. Repeat this for all three coils, moving the needle backprobe from one "cyl" wire to the next. If you have a good strong spark at all the coils we will have to find another reason for the no start


Let me know if you have spark, and always let me know if you are unclear on anything I ask you to do.



Customer: replied 8 years ago.

Still no spark


If you have no spark with power to the coil and grounding the control manually you have a bad spark checker or a bad coil.
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Customer: replied 8 years ago.
Ok got it sorted baack running put a new crank sensor on problem solved thanks again for your help Laughing

I don't understand how you can have a pulse if you don't have a good crank sensor so check the connector and wiring.


I am glad you got it running again


Thank you



Customer: replied 8 years ago.
I guess there was enough to show on the meter but not enough to fire off a spark signal ? ,but you came through again thanks

I would have a code and data reader ready that will show RPM when cranking. As long as you have 300 or so cranking RPM you have a crank pulse.


You are going to be a Hyundai tech by the time you get done with this!!


Thanks again