Ok this is for my LE5/L61 hybrid engine, but thats not whats important.


On my megasquirt, I am not getting a crank signal. This setup hasnt been ran because of that.

I have a hall effect crank sensor with this wiring.
3 wires:

1.CKP SIG
2.Low Ref
3.5v Ref

Now, I hooked a Oscilloscope up to the LE5 sensor and am not getting anything from the sensor. I have 5volts going to it, CKP wire going to the Oscilloscope and the Low Ref grounded.

Does that sound right? Ive had the CKP to the ECM and the others stayed the same and I cannot get a crank signal.

The sensor came with the engine so I have no reason to think the air gap is wrong or it is bad.

Am I missing something or the oscilloscope isnt setup right or is the sensor not working?

No sounds like you have it connected correctly.
Sure you have the volts scale turned down, time base to a slow rate and adjust the trigger.

If you can touch the probe to the +5 and see the pulse I would think you should see the signal if it's there. I would guess it would set high and drop when the Hall fires since the ones I've worked with usually do a ground pulse..

quote Originally posted by Dodgerunner: No sounds like you have it connected correctly. Sure you have the volts scale turned down, time base to a slow rate and adjust the trigger. If you can touch the probe to the +5 and see the pulse I would think you should see the signal if it's there. I would guess it would set high and drop when the Hall fires since the ones I've worked with usually do a ground pulse..

So put the scope on the 5v wire and see what happens when the engine is cranking?

I've got the directions at home and can post them this evening if no help by then, but this can be tested using a regular multimeter as well. Let me see if I can dig it up on my home computer from here at work, depends on the filters here at work.

Found the following on Wikipedia at link : http://en.wikipedia.org/wiki/Hall_effect

Automotive ignition and fuel injection
Commonly used in distributors for ignition timing (and in some types of crank and camshaft position sensors for injection pulse timing, speed sensing, etc.) the Hall effect sensor is used as a direct replacement for the mechanical breaker points used in earlier automotive applications. Its use as an ignition timing device in various distributor types is as follows. A stationary permanent magnet and semiconductor Hall effect chip are mounted next to each other separated by an air gap, forming the Hall effect sensor. A metal rotor consisting of windows and tabs is mounted to a shaft and arranged so that during shaft rotation, the windows and tabs pass though the air gap between the permanent magnet and semiconductor Hall chip. This effectively shields and exposes the Hall chip to the permanent magnet's field respective to whether a tab or window is passing though the Hall sensor. For ignition timing purposes, the metal rotor will have a number of equal-sized tabs and windows matching the number of engine cylinders. This produces a uniform square wave output since the on/off (shielding and exposure) time is equal. This signal is used by the engine computer or ECU to control ignition timing. It is worth noting that many automotive Hall effect sensors have a built-in internal NPN transistor with an open collector and grounded emitter, meaning that rather than a voltage being produced at the Hall sensor signal output wire, the transistor is turned on providing a circuit to ground though the signal output wire.

As Dodgerunner has suggested, the Hall sensor may be pulling the CKP SIG line to ground, resulting in no output voltage to measure.A simple circuit of a pull up resistor powered by a few batteries may allow the output of the Hall sensor to be viewed on an Oscilloscope.

Ok, this may not fully apply to your application, but this is how I test mine:

The directions may not all apply to your app.

Measure the signal while the sensor is still installed by unplugging the sensor at the cable connections at the firewall to the drivers side of the engine. Measure voltage here as the engine is being cranked. Use a low voltage setting on a digital volt meter, preferably in an alternating current setting if available in a low voltage setting. If no signal is detected, the unit is suspect. The other simple measurement is to unplug the unit (without removing it from its location behind the engine on top of the transmission housing). Check all 3 terminals for resistance or an open circuit. The new sensor measured about 160 ohms between the center lug and a side lug. My old defective unit had no continuity and no measurable resistance.

[This message has been edited by Rainman (edited 06-25-2008).]

Figures I just got called into work for 2pm, so i cant mess with it today but i got all day tomorrow. Thanks guys.

One other thing; I do not have the probe that came with the Scope. So I have a gator clip on the outside ring on the scope and a wire inside. The gator clip I am grounding to the engine (actually tried grounding it to the sensor and not grounding at all)

Does that sound right? (grounding to the chassis, and center to the sensor wiring?)

quote Originally posted by StockGT: Found the following on Wikipedia at link : http://en.wikipedia.org/wiki/Hall_effect Automotive ignition and fuel injection Commonly used in distributors for ignition timing (and in some types of crank and camshaft position sensors for injection pulse timing, speed sensing, etc.) the Hall effect sensor is used as a direct replacement for the mechanical breaker points used in earlier automotive applications. Its use as an ignition timing device in various distributor types is as follows. A stationary permanent magnet and semiconductor Hall effect chip are mounted next to each other separated by an air gap, forming the Hall effect sensor. A metal rotor consisting of windows and tabs is mounted to a shaft and arranged so that during shaft rotation, the windows and tabs pass though the air gap between the permanent magnet and semiconductor Hall chip. This effectively shields and exposes the Hall chip to the permanent magnet's field respective to whether a tab or window is passing though the Hall sensor. For ignition timing purposes, the metal rotor will have a number of equal-sized tabs and windows matching the number of engine cylinders. This produces a uniform square wave output since the on/off (shielding and exposure) time is equal. This signal is used by the engine computer or ECU to control ignition timing. It is worth noting that many automotive Hall effect sensors have a built-in internal NPN transistor with an open collector and grounded emitter, meaning that rather than a voltage being produced at the Hall sensor signal output wire, the transistor is turned on providing a circuit to ground though the signal output wire. As Dodgerunner has suggested, the Hall sensor may be pulling the CKP SIG line to ground, resulting in no output voltage to measure.A simple circuit of a pull up resistor powered by a few batteries may allow the output of the Hall sensor to be viewed on an Oscilloscope.

Can someone clarify on that? lol I think im mixxed up. So when the the teeth go by on the crank, it would close the circuit to the ground via CKP line? Resulting in what a resistance? I dont think im understanding how the friggin thing is working!!!

kind of off topic, yet related. what o-scope are you using? im wanting to know because i want to get one. and im not sure if a usb one will be reliable or accurate enough to use.

theres how its setup now

Found a web site with details on MegaSquirt systems : http://www.megamanual.com/ms2/pickups.htm

Do you have a part number on your Hall effect crank sensor ? It could help determine the type of output signal.

quote Originally posted by StockGT: Found a web site with details on MegaSquirt systems : http://www.megamanual.com/ms2/pickups.htm Do you have a part number on your Hall effect crank sensor ? It could help determine the type of output signal.

No I dont is there a way to get it off the internet? I know the motor is from a 2.4L 2007 Cobalt SS sedan, and is a hall-effect. But as far as numbers go I dont know.

PM sent

I don't have any advice, but I do have this, which I came up with to save sanity after hearing a certain song too often:

Current flows from C to E
Magnetic field changes H_fe
That's called the Hall Effect, girl
That's called the Hall Effect, girl
Q₁ is biased with I₁ low
The magnet makes the current flow
That's called the Hall Effect, girl
That's called the Hall Effect, girl

...without any apologies to Gwen Stefani whatsoever.

Ed

PS "Hollaback Girl", in case anyone was wondering.

Bump for more ideas.


lol nice song, i had to listen to it and put the words in there.

hmm sounds like something that i used back in elec tech my junior year of highschool