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crank sensor voltage

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Old 11-30-2006, 06:17 PM
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Originally Posted by 2002_Z28_Six_Speed
Even if the stock vehicle needs a crackshaft position relearn it will still fire and run.

You would think the MSD will still fire also, just at the wrong time.



a msd tech told me, if the cam and crank sensor are not in time
with each other within a few degrees, that the msd box is hit or miss
as far as firing
Old 11-30-2006, 09:12 PM
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also, what shape is the timing chain in? are you sure the crank and cam gears are timed properly?
Old 11-30-2006, 10:29 PM
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ok. inductive pickup. permanent magnet surrounded by coiled up wire. as the reluctor wheel's teeth pass the sensor, it acts on the magnet field created by the permanent magnet. as each tooth passes, it "pulls" on that magnetic field. anytime you move a magnetic field perpendicular to a wire, you induce voltage. hence the name "inductive" pickup. true the voltage produced is small(usually measured in AC millivolts) but it's there. its output viewed on an oscilliscope would be a sine wave. a hall-efect sensor works differently. it has a permanent magnet across from a semiconductor. as current flows through it, its output changes from high to low as the magnetic field either acts or does not act on the semiconductor. that action(or the lack thereof, however you want to look at it) is created by moving a piece of metal either inbetween or from inbetween the magnet and semiconductor. whenevr that metal is between the magnet and semiconductor, the semiconductor cant "see"(for simplicity's sake) the magnetic field and its output is low. when the metal is moved from inbetween the magnet and semiconductor, the semiconductor can "see" the magnetic field, and its output goes high. as viewed on an oscilliscope it would appear as a square wave more than anything else, and it would be a DC, almost digital-like, voltage(remember, the inductive pickup created an AC voltage). it acts almost like a switch. this is just a quick five -minute lesson on the difference between the two sensor types. being that this is the advanced section of ls1tech, i figured i'd throw this bit in. FWIW, different OEMS use the sensors interchangably(sp?). for example, GM may use a hall-effect sensor, whereas Ford would use an inductive pickup in the exact same situation. take an ABS wheel speed sensor. some are magnetic pickup, some are hall effect. the same can be applied to, crank sensors, cam sensors, etc.
Old 12-01-2006, 07:54 AM
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Originally Posted by slowpoke96z28
also, what shape is the timing chain in? are you sure the crank and cam gears are timed properly?


chain is new ls2
timing has been checked and rechecked

it also started 3 times, seems to run fine then
Old 12-01-2006, 10:04 AM
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Nevermind, I see that you have replaced it. I would definitely check reluctor runout if I was you.
Old 12-01-2006, 10:18 AM
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Originally Posted by S10slepper
can anyone tell me how much voltage should be going threw the crank sensor? and how much should come out off it?

my cam sensor sends a nice clean 5 volts.
but the crank sensor sends 1.5 to 2 volts and its very eradick(sp)
if this is in the wrong section please move it.
thanks in advance, matt
You have what is known as a VR sensor. Variable Reluctance. Ok class. VR sensors have a AC current output. A typical GM VR sensor output at cranking is around 1.0-1.2 volts. the voltage will increase with RPM at 6,000rpm the same sensor will now put out almost 70volts. If you wish to read the output of the crank sensor with a DVOM ( digital Volt Ohm Meter ) you need to set it to AC current. The best thing to use however is an osciliscope and if you can get the picture up here in a screen shot.

However the problem could be in the camshaft position sensor I do belive these PCM can and will run withouth CMP. If you would like to check it however it is a Hall Effect is has a 12 volt supply a Ground and a % volt signal return. The pattern should be on for 24 teeth on a ls1 Reluctor on the crank and the ls2 should be 58teeth then a notch. The cam should be high for one rotation and low for the next.

Check the simple stuff first. Power and ground lines.

Sean
Old 12-01-2006, 12:16 PM
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engine WILL run if only the camshaft position sensor is lost. it may experince a couple seconds longer cranktime befor it runs. it will run though. i wouldnt even worry about the CMP sensor. not to sound like a jerk, but the camshaft position sensor works the same way as a crankshaft position sensor on an LS1. its not hall-effect!! what did the techs from MSD say? and you still didnt say how the MSD box is interfaced with the factory sensors, nor what MSD box you are using. that would be a big help.
Old 12-01-2006, 01:50 PM
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Originally Posted by slowpoke96z28
engine WILL run if only the camshaft position sensor is lost. it may experince a couple seconds longer cranktime befor it runs. it will run though. i wouldnt even worry about the CMP sensor. not to sound like a jerk, but the camshaft position sensor works the same way as a crankshaft position sensor on an LS1. its not hall-effect!! what did the techs from MSD say? and you still didnt say how the MSD box is interfaced with the factory sensors, nor what MSD box you are using. that would be a big help.


msd part #6010
6ls
not sure what you mean buy interface?
msd plugs directly into crank and cam sensors,
and coil packs, other that it only has 3 wires 1 hot 2 grounds
sounds really simple????
that is the entire ignition system
like i said before this ran perfect on my 346
Old 12-01-2006, 11:18 PM
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Originally Posted by S10slepper
msd part #6010
6ls
not sure what you mean buy interface?
msd plugs directly into crank and cam sensors,
and coil packs, other that it only has 3 wires 1 hot 2 grounds
sounds really simple????
that is the entire ignition system
like i said before this ran perfect on my 346
Msd box will not work without cam reference.
Old 12-01-2006, 11:26 PM
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Originally Posted by slowpoke96z28
engine WILL run if only the camshaft position sensor is lost. it may experince a couple seconds longer cranktime befor it runs. it will run though. i wouldnt even worry about the CMP sensor. not to sound like a jerk, but the camshaft position sensor works the same way as a crankshaft position sensor on an LS1. its not hall-effect!! what did the techs from MSD say? and you still didnt say how the MSD box is interfaced with the factory sensors, nor what MSD box you are using. that would be a big help.
The CMP is in fact a hall effect 1 12v supply 1ground 1 signal a square wave output. A camshaft with a pattern like the Ls1 will not generate sufficient velocity to generate enough voltage for a VR sensors to work properly. Here is the diagram.
Attached Thumbnails crank sensor voltage-cmp.jpg  
Old 12-02-2006, 07:47 AM
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one thing to do is make sure the plugs aren't fouled-out from all this cranking you've probably been doing. i say this because you say you've replaced just about everything else in the ignition, and probably tried to get the motor to start after each time you changed something. next, is this a carb setup or efi? are you using pro-data+ to program to box? then, check for 12v on pin C and ground on pin B of the crank and cam sensor connectors. that will tell us that the msd box is at least cutting on and trying to work. check that and answer the questions. NOW back to the sensor deal. if you look in the schematic in the above post, you'll notice that there is solid state circuitry in each sensor. a true hall-effect device does not need solid state circuitry to produce a square wave. also, it requires a hall device and a permanent magnet, seperated by space, with the reluctor passing between them. the crank and cam sensors do not have this. what they have is what amounts to 2 ABS wheel speed sensors mounted side by side, one reading one track of the reluctor, and the other reading the other track(if you take a ls1 crank or cam and lay it on its side, you'll notice that the reluctors have 2 tracks that are exact opposites of each other) the solid state circuitry takes the output of both sensors, amplifies it, and creates a square wave output. i'm not sure if it amplifies the 2 signals before it creates the square wave, or creates the square wave first, and then amplifies that. however, either way, its not hall-effect. they both rely on magnetism and the ability of a magnetic field to deflect flowing electrons(the lorentz force. had to look that one up ), but thats pretty much where the similarities end.
Old 12-02-2006, 09:21 AM
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Originally Posted by slowpoke96z28
one thing to do is make sure the plugs aren't fouled-out from all this cranking you've probably been doing. i say this because you say you've replaced just about everything else in the ignition, and probably tried to get the motor to start after each time you changed something. next, is this a carb setup or efi? are you using pro-data+ to program to box? then, check for 12v on pin C and ground on pin B of the crank and cam sensor connectors. that will tell us that the msd box is at least cutting on and trying to work. check that and answer the questions.




Originally Posted by slowpoke96z28
NOW back to the sensor deal. if you look in the schematic in the above post, you'll notice that there is solid state circuitry in each sensor.
The only solid state circutry is in the CMP CKP sensor. It would appear that Both are in fact Hall effect sensors which is odd. I never have to actually test them as they never seem to fail.GM has been on a VR cranksensor kick for just about forever. odd.

This is directly comming from the Factory manual.


Camshaft Position (CMP) Sensor Operation

The Camshaft Position (CMP) sensor is mounted through the top of the engine block at the rear of the valley cover. The CMP sensor works in conjunction with a 1X reluctor wheel on the camshaft. The CMP sensor is used to determine whether a cylinder is on the firing or the exhaust stroke. As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The CMP sensor internal circuitry detects this and produces a signal which is used by the PCM. The PCM uses this signal in combination with the CKP 24X signal to determine crankshaft position and stroke.

Observe that as long as the PCM receives the Crankshaft Position sensor 24X signal, the engine will start. The PCM can determine top dead center for all cylinders by using the Crankshaft Position sensor 24X signal alone. The Camshaft Position sensor 1X signal is used by the PCM to determine if the cylinder at top dead center is on the firing stroke, or the exhaust stroke. The system attempts synchronization and looks for an increase in engine speed indicating the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes it incorrectly synchronized to the exhaust stroke and re-synchronizes to the opposite cam position. A slightly longer cranking time may be a symptom of this condition.



Originally Posted by slowpoke96z28
a true hall-effect device does not need solid state circuitry to produce a square wave. also, it requires a hall device and a permanent magnet, seperated by space, with the reluctor passing between them. the crank and cam sensors do not have this.
Yes a true hall effect device actually needs Current to work. It requires current to create a high state field to collapse. Do Some reading on automotive sensor design.the field is interupted and a transistor in the sensor take the signal up or down. Thats how a hall effect has worked since my carrer began in 1992.


Originally Posted by slowpoke96z28
what they have is what amounts to 2 ABS wheel speed sensors mounted side by side, one reading one track of the reluctor, and the other reading the other track(if you take a ls1 crank or cam and lay it on its side, you'll notice that the reluctors have 2 tracks that are exact opposites of each other) the solid state circuitry takes the output of both sensors, amplifies it, and creates a square wave output.
Actually no you are again describing VR sensors which are AC~ Voltage generators. Those bad dads work by creating a positive and a negative signal and the Module looks for the zero crossing.



Originally Posted by slowpoke96z28
i'm not sure if it amplifies the 2 signals before it creates the square wave, or creates the square wave first, and then amplifies that. however, either way, its not hall-effect. they both rely on magnetism and the ability of a magnetic field to deflect flowing electrons(the lorentz force. had to look that one up ), but thats pretty much where the similarities end.
What is it that you do for a living again??? ASE Certified Master Mechanic here.

the opposite wheel track is for reverse roatation detection.
Old 12-02-2006, 12:16 PM
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The 24X reluctor doesn't send a perfect 50% duty cycle square wave since it uses the width to help with the position sync. But it averages to that.

http://www.ls2.com/forums/showthread...hreadid=471360
Old 12-02-2006, 01:09 PM
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.....

Last edited by TTD; 12-22-2007 at 01:30 PM.
Old 12-02-2006, 03:09 PM
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allright bubble busting time. since someone wants to get on SI and copy from it, lets continue with that philosophy. I didnt want to go there, but oh well.

Document ID# 761508
2002 Chevrolet Camaro


--------------------------------------------------------------------------------

Electronic Ignition (EI) System Description
The electronic ignition (EI) system is responsible for producing and controlling a high energy secondary spark. This spark is used to ignite the compressed air/fuel mixture at precisely the correct time. This provides optimal performance, fuel economy, and control of exhaust emissions. This ignition system consists of a separate ignition coil connected to each spark plug by a short secondary wire. The driver modules within each coil assembly are commanded ON/OFF by the powertrain control module (PCM). The PCM primarily uses engine speed and position information from the crankshaft and camshaft position (CMP) sensors to control the sequence, dwell, and timing of the spark. The EI system consists of the following components:

Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor is a three wire sensor based on the magneto resistive principle. A magneto resistive sensor uses two magnetic pickups between a permanent magnet. As an element such as a reluctor wheel passes the magnets the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The PCM supplies a 12-volt, low reference, and signal circuit to the CKP sensor. The sensor returns a digital ON/OFF pulse 24 times per crankshaft revolution.

Crankshaft Reluctor Wheel
The crankshaft reluctor wheel is mounted on the rear of the crankshaft. The wheel is comprised of four 90 degree segments. Each segment represents a pair of cylinders at TDC , and is further divided into six 15 degree segments. Within each 15 degree segment is a notch of 1 of 2 different sizes. Each 90 degree segment has a unique pattern of notches. This is known as pulse width encoding. This pulse width encoded pattern allows the PCM to quickly recognize which pair of cylinders are at top dead center (TDC). The reluctor wheel is also a dual track-or mirror image-design. This means there is an additional wheel pressed against the first, with a gap of equal size to each notch of the mating wheel. When one sensing element of the CKP sensor is reading a notch, the other is reading a set of teeth. The resulting signals are then converted into a digital square wave output by the circuitry within the CKP sensor.

Camshaft Position (CMP) Sensor
The CMP sensor is also a magneto resistive sensor, with the same type of circuits as the CKP sensor. The CMP sensor signal is a digital ON/OFF pulse, output once per revolution of the camshaft. The CMP sensor information is used by the PCM to determine the position of the valve train relative to the CKP.

Camshaft Reluctor Wheel
The camshaft reluctor wheel is either pressed onto the camshaft or part of the timing gear depending on the application. The feature-or target- is read in a radial or axial fashion respectively. The wheel is a smooth track, half of which is of a lower profile than the other half. This feature allows the CMP sensor to supply a signal as soon as the key is turned ON, since the CMP sensor reads the track profile, instead of a notch.



how about posting the whole thing, instead of just the parts that make you sound right?

not once does it mention hall-effect.

and i never said hall-effect or magneto-resistive devices didnt require power or current flow, i said it didnt require a solid state device to produce a square wave. in fact, i made many references to the lorentz force, which REQUIRES current flow. so where did i saw hall-effect devices dont require current flow? why dont you try doing some research on magneto-resistive sensors, giant magneto-resistive sensors, magneto-inductive sensors, hall-effect sensors and so on, and quit copying what some General Motors maintenance engineer wrote in SI. FWIW, i work on duramax's for a living, not gen III or gen IV small blocks, so i'm not going to claim i know more about them than you. i do know what i'm talking about here, though. i got alot of respect for you car techs. you guys flag like 3 times what us truck techs do. i respect your knowledge and experience on GMs. dont be mad if i PM you with a problem vehicle now since i know what you do for a living.
Old 12-03-2006, 01:27 AM
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Hall effect can even be a VR By your wayward definition then all magnetically based sensors would in fact be magnetic resistive if you want to argue over semantics. The factory crank sensors would in fact be Halleffect Digital On/off switchs,. Enjoy.

Here since you so cleverly clipped the wikipedia on your first reply to this post.

http://en.wikipedia.org/wiki/Hall_effect


here is another definition.


http://en.wikipedia.org/wiki/Hall_effect_sensor


Ah i forgot another internet seach function junkie.

Glad to see you creditied the wikipedia for the knowledge you so willinging ripped off.


Originally Posted by slowpoke96z28
allright bubble busting time. since someone wants to get on SI and copy from it, lets continue with that philosophy. I didnt want to go there, but oh well.

Document ID# 761508
2002 Chevrolet Camaro


--------------------------------------------------------------------------------

Electronic Ignition (EI) System Description
The electronic ignition (EI) system is responsible for producing and controlling a high energy secondary spark. This spark is used to ignite the compressed air/fuel mixture at precisely the correct time. This provides optimal performance, fuel economy, and control of exhaust emissions. This ignition system consists of a separate ignition coil connected to each spark plug by a short secondary wire. The driver modules within each coil assembly are commanded ON/OFF by the powertrain control module (PCM). The PCM primarily uses engine speed and position information from the crankshaft and camshaft position (CMP) sensors to control the sequence, dwell, and timing of the spark. The EI system consists of the following components:

Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor is a three wire sensor based on the magneto resistive principle. A magneto resistive sensor uses two magnetic pickups between a permanent magnet. As an element such as a reluctor wheel passes the magnets the resulting change in the magnetic field is used by the sensor electronics to produce a digital output pulse. The PCM supplies a 12-volt, low reference, and signal circuit to the CKP sensor. The sensor returns a digital ON/OFF pulse 24 times per crankshaft revolution.

Crankshaft Reluctor Wheel
The crankshaft reluctor wheel is mounted on the rear of the crankshaft. The wheel is comprised of four 90 degree segments. Each segment represents a pair of cylinders at TDC , and is further divided into six 15 degree segments. Within each 15 degree segment is a notch of 1 of 2 different sizes. Each 90 degree segment has a unique pattern of notches. This is known as pulse width encoding. This pulse width encoded pattern allows the PCM to quickly recognize which pair of cylinders are at top dead center (TDC). The reluctor wheel is also a dual track-or mirror image-design. This means there is an additional wheel pressed against the first, with a gap of equal size to each notch of the mating wheel. When one sensing element of the CKP sensor is reading a notch, the other is reading a set of teeth. The resulting signals are then converted into a digital square wave output by the circuitry within the CKP sensor.

Camshaft Position (CMP) Sensor
The CMP sensor is also a magneto resistive sensor, with the same type of circuits as the CKP sensor. The CMP sensor signal is a digital ON/OFF pulse, output once per revolution of the camshaft. The CMP sensor information is used by the PCM to determine the position of the valve train relative to the CKP.

Camshaft Reluctor Wheel
The camshaft reluctor wheel is either pressed onto the camshaft or part of the timing gear depending on the application. The feature-or target- is read in a radial or axial fashion respectively. The wheel is a smooth track, half of which is of a lower profile than the other half. This feature allows the CMP sensor to supply a signal as soon as the key is turned ON, since the CMP sensor reads the track profile, instead of a notch.



how about posting the whole thing, instead of just the parts that make you sound right?

not once does it mention hall-effect.

and i never said hall-effect or magneto-resistive devices didnt require power or current flow, i said it didnt require a solid state device to produce a square wave. in fact, i made many references to the lorentz force, which REQUIRES current flow. so where did i saw hall-effect devices dont require current flow? why dont you try doing some research on magneto-resistive sensors, giant magneto-resistive sensors, magneto-inductive sensors, hall-effect sensors and so on, and quit copying what some General Motors maintenance engineer wrote in SI. FWIW, i work on duramax's for a living, not gen III or gen IV small blocks, so i'm not going to claim i know more about them than you. i do know what i'm talking about here, though. i got alot of respect for you car techs. you guys flag like 3 times what us truck techs do. i respect your knowledge and experience on GMs. dont be mad if i PM you with a problem vehicle now since i know what you do for a living.
Old 12-03-2006, 04:40 AM
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um, what makes you think i referenced wikipedia? who in their right mind would reference wikipedia as a reliable source? anybody that can type can make an article on a topic. doesnt make it right. i dont take wikipedia as gospel, so why would i bring it here as gospel? what i posted comes from physics being my favorite subject, what i learned in various trade schools, SAE papers ,etc. oh, i did rip off SI in post #35, but i do believe it was credited. and i did search the net for more info on the MSD 6010 box the kid was using to find out what pins he needed to check, sorry for being a thorough "internet search junkie" in that regard. i didnt know i'd get flamed for wanting to learn more about the MSD box before i tried to help the guy.

whats most important is that we help this kid get his car running. we know now that there are at least 2 GM techs reading this thread, so we should be able to figure it out. lol, i would say check for bulletins...
Old 12-03-2006, 05:01 AM
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Please do not quote Wikipedia. As the general public creates the articles and the people don't have technical expertise it is not a good reference. Many of those people will actually revert articles back when you correct the. Power trips...

Besides, look up an article there. Then, go to Google. Half the time they just copied one of the first sites that pops up on Google about that topic.

I have read more inaccurate articles in Wikipedia than I have seen in every textbook in my life.
Old 12-03-2006, 03:56 PM
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Old 12-06-2006, 07:13 PM
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well, is the motor back running?


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