Smacked the crank position sensor with a hammer...gulp

Hey Folks,

New to the forum. Is this where the cool kids hang out?

I have a 2007 Mazda3, 162k miles. I was changing a cv joint and bearings etc. and waiting on some parts so the car sat for a few weeks so I had it on a trickle charger Ive used many time before. It was running fine right when I drove it into my garage.

I finished the work and went to start it and it turns over but no start.

Anyway while pounding the cv axle back into place I accidently hit the 3-wire crank position sensor (CPS). Enough to crack an arm ever so slightly but its still all in one piece and it does not flex.



I didnt touch any other sensor or wiring other than the CPS during this repair.

I thought maybe I pinched the harness for the CPS so I pulled the tape and the wires looked ok.


I then backprobed the CPS and got 12v , ground and 5volts with the CPS connected and KEY ON. I don't have an oscilloscope. I turned the motor by hand while I watched the multimeter but it read a stead 4.999.



Tachometer doesn't move when cranking motor.

I check the distance/gap to the teeth on main pulley and its in spec. 0.5 - 1.5mm.

Could I have broken the CPS that easily?

Yes. This is where the cool kids hang-out. While you're waiting for one of them to show up, (since I hang out here, too,) I will offer this, :

A 3-wire hall-effect sensor should toggle voltage on the signal wire when the magnetic field is interrupted. Remove the sensor from the car, but leave it connected to the wiring harness. With a volt meter on the signal wire, KOEO, observe the voltage. Now, slowly wave metal object, such a wrench, back and forth across the the sensor. Does the voltage toggle high to low? If not, it is safe to say that the sensor is defective. If the voltage does toggle, re-install and double check the sensor position and air-gap.

Chad YOU ARE COOL!

I cant thank you enough for your assistance. I tried that on the car, I will try it off the car.

Another question: I used a LoadPro on the 12volt line and ground, I got 12.16 volts and then 11.90 when loaded. Is that voltage drop enough to cause an issue with the CPS?

Another question: when I use the Loadpro on the 5volt/signal and ground wire, I went from 4.999 to 0,038 volts and heard the fuel pump or something activating. Is that of any relevance?

LEARNING!

loademup wrote:

Another question: I used a LoadPro on the 12volt line and ground, I got 12.16 volts and then 11.90 when loaded. Is that voltage drop enough to cause an issue with the CPS?

I wouldn't be too concerned with that.

Another question: when I use the Loadpro on the 5volt/signal and ground wire, I went from 4.999 to 0,038 volts and heard the fuel pump or something activating. Is that of any relevance?

That proves that the signal wire is good, and not shorted.

Chad she was definitely broken. As soon as I plugged in the new CPS and placed a metallic object near it the volts dipped down and all sorts of clicks and motors starting activating.

Car started right up.

Loadpro helped me figure out I had a good wiring harness which was helpful. Its a cool tool.

Thanks so much for your help. You are cool!

Nice. I'm glad you got it running. Good job!

( < Notice my cool sunglasses)

Do you wear them at night? If so...you're TRULY cool.

I am embracing my new-found coolness. I, now, wear them, even, when I sleep.

This we need to see, my friend! Chad in his PJs with sunglasses on.

Is he awake or his asleep? No one knows!

Try your voltmeter...one in each wear, see what reading you get.

As a designer of CAM and CNK targets matched to Hall and VRS pickups, I can say the CNK target on this engine cross section is a lot smaller than I would expect, it is very thin, probably to keep the weight down or due to having limit mounting clearance. What this means is if there is any misalignment in the sensor relative to the CNK wheel the sensor will not work properly. Specifically, look at the sensor mounting bosses on the engine, this surface should be as flat and clean as possible without any debris that could skew the sensor relative to the target. So you need to clean up the mounting surfaces. If after you mount the sensor it can still move due to the crack, then it needs to be replaced. The sweet spot on the sensor face relative to the target is very unforgiving on this engine. If you replace the sensor make sure it is original OEM.

Agree with MarkBeck

Non Genuine Sensors can be bad straight out of the box. Having a Scope to measure the output from the Old and then the New is essential in my view, then you ILL know if you have bought a faulty part

Having a scope is the saving grace, only then can you get a precise look at what AMPLITUDE Voltage & PATTERN the sensor is actually transmitting to the ECU.

Scanner Danner lives by the advantage of using a scope, just get the one you can afford for now - for sure its better than no scope.