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I did a voltage drop test on my crank sensor and need guidance on if i did it correctly and if my readings are what is expected. I have a 2006 chevy express with a 6.0. Here is what i did, I connected one red wire directly to the positive side of the battery and the other red wire to either the signal or power side of the sensor using a back probe. I then tested the ground of the sensor by connecting one of the black wires directly to the negative post of the battery and the other to the ground wire of the sensor plug again using a back probe. I did the test with the KOEO then again with the engine running. Below is my results. Any help is greatly appreciated. In the picture of the plug below the middle purple wire was connected to the blue back pin wire, yellow to yellow and green to green.
You know these things usually go a lot better when you start by telling us WHY you are messing with the CKP sensor in the first place.. What PROBLEM do you have? What are you trying to solve?????
You are down a rabbit hole.. You might not need to be down that rabbit hole at all. NO ONE wants to join in your rabbit hole without understanding first-why you are in that rabbit hole. Does that make any sense?
I have NO IDEA what you are trying to accomplish therefor I'm not sure what I can do to help you.
You are asking about which wire at the PCM is the power supply for your CKP.. lt1swap.com Connector Pin
Blue 12 CKP sensor signal
Blue 21 CKP sensor ground (-)
I "believe" that the 12V power supply for the CKP sensor comes from the fuse/load box. If your CKP used a 5V+ reference signal, it would get that signal from the PCM. Since it uses 12V+, it is likely powered from the fuse box, like the O2 sensor heaters, MAF sensor, etc;
Again, why are you checking all of this stuff? If you are having a problem-tell us what the problem is and I'm sure someone here has had experience with it.
My experience has been as soon as I give information about my problem people lose interest in trying to help me. I've had several post with detailed information about what I've done what my problem was and things I've tried. At this point I'm just trying to get one small diagnostic step at a time so that at least I can get some help. I'm not trying to be ungrateful just trying a different approach to get some help. My other post "6.0 P0336 error code" from 7/26 has all the details of the problem and what i have done.
My experience has been as soon as I give information about my problem people lose interest in trying to help me. I've had several post with detailed information about what I've done what my problem was and things I've tried. At this point I'm just trying to get one small diagnostic step at a time so that at least I can get some help. I'm not trying to be ungrateful just trying a different approach to get some help. My other post "6.0 P0336 error code" from 7/26 has all the details of the problem and what i have done.
ive read all 3 of your posts on this issue and im still confused as to what your issue is.
are there any other issues with the vehicle other than the code? if so please explain
do u have any access at all to repair information to diagnose the code? if not please provide me with year make model and I can possibly send it to you
also u cant effectively do a voltage drop test with a multimeter by itself because u are not simulating a load your just measuring voltage. 12 volts can conduct thru one strand of copper with no load or even a broken wire that's broken inside the jacket and is touching 12 volts can conduct as well. 12 volts can even conduct through your body as very small loads. but when u load the circuit that's when u find out what kind of voltage drop u have.
so do this take a test light THAT IS NOT AN LED connect it to a known good ground AKA battery negative insert this into the 12v+ terminal and while doing that measure your voltage on that terminal while the bulb is illuminated if it even illuminates.
now reverse this and test the ground side while putting your test light clamp and multimeter positive lead on the positive battery terminal
post those results and don't assume people don't wanna help.
Jkwalkercchs thanks for the help. I have been out of the country on vacation. Let me start over. I have a 2006 chevy express 2500 with a 6.0 vortec. I do not have access to the repair information. I have rebuilt the motor with a new crank and a slightly larger cam (pic of cam description attached). When i start the motor it runs fine for about a minute to a minute and half. Up to this point there is no code. The motor starts to cut out almost like the motor is loading up with fuel and then i get a P0336 code. The motor then runs progressively worse. At that point if i clear the code and restart the motor immediately the code will come back and the motor will run but misses (it never backfires). If i clear the code and let it sit over night and start it it again it will run fine and will not set the code till about a minute into running when it starts to miss again. I am not sure if the missing happens first or the setting of the code. I have taken a known good crank sensor from another 2006 6.0 vortec and tried it but there is no difference in how the motor runs. I also went to the junk yard and scavenged a crank sensor plug and i cut its wires at the PCM. I then used that plug and wires with connected it with scotchlok connectors about 2 in out of the PCM and connected it to the crank sensor. The motor had the same symptoms (I did not cut my old sensor wires). There is no other codes that gets set. I will run the drop test with the factory wiring and plug this evening and post my results but tornado warning are going off right now.
If it was a physical problem with the reluctor wheel why do you think it would run okay for a minute or so? Does the computer wait for a minute or two before it starts looking at the crank sensor? I just don't know much about the computers sequence and functions between the sensors.
If it was a physical problem with the reluctor wheel why do you think it would run okay for a minute or so? Does the computer wait for a minute or two before it starts looking at the crank sensor? I just don't know much about the computers sequence and functions between the sensors.
I think you have another issue causing a false code that's making you chase your tail
is the pcm tuned?
because on a cold crank its running strictly off the VE map until it comes up to temp and the fuel trims start working...........study up on open and closed loop fueling to get a better understanding of this
when its running in VE mode it could be rich/lean or whatever and run halfway decent at idle. now when it starts correcting the VE table may be so far off that the truck is reaching the limits of what it can correctly adapt to fast enough to have stable fueling. so the erratic crank signal could just be because the engine is stumbling so bad the pcm comprehends this as a bad crank signal.
Jkwalkercchs thank you for the direction, that makes a lot of sense with the symptoms I am having. I have not had the motor tuned yet. I have been trying to get it tuned but I've been struggling to find a tuner that will even attempt tuning with a p0336 code. I will read up tonight on the open closed loop process and VE mapping. Thanks again for all your help.
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Crank Sensor voltage drop test help 
