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Discussion Starter · #1 ·
Hello people!
I have a Mazda CX-7 2010 with a 2.3l turbo, I had to pull the engine because the flywheel had broken teeth I put everting in the way it should be and I’m getting no spark at all, I am getting power to the coils and the coils are good, so are the spark plugs, I also make sure that the crankshaft position sensor was at the 20th tooth, and I did that with cylinder number 1 at TDC. All grounds are connected as well, there is no blown fuses I’ve checked them all. It was running before I pulled it. I’m lost on what to check now.


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One likely suspect is a wiring harness connector that didn't get 'clicked' all the way in. The 'easiest' thing to do is start disassembling and check each connector as you go (and hope it's not the last one left to check).
 

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Discussion Starter · #3 ·
One likely suspect is a wiring harness connector that didn't get 'clicked' all the way in. The 'easiest' thing to do is start disassembling and check each connector as you go (and hope it's not the last one left to check).
Ok then that’s what I’ll start doing, should I pull the whole wiring harness or don’t go that far into it?
 

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Try checking for reference voltage and ground at the crank sensor connector while a helper cranks the engine. If voltage and ground are ok, then wave form on the signal wire should be checked by backprobing at the connector or by using a wire piercing adapter. You would need a scope to do that testing, so if you can't get access to one, then maybe you can find a travelling mechanic who can do that testing for you.
 

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Discussion Starter · #8 ·
Try checking for reference voltage and ground at the crank sensor connector while a helper cranks the engine. If voltage and ground are ok, then wave form on the signal wire should be checked by backprobing at the connector or by using a wire piercing adapter. You would need a scope to do that testing, so if you can't get access to one, then maybe you can find a travelling mechanic who can do that testing for you.
Can I use a multimeter to check for volt and ground on the crankshaft connector?
 

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Can I use a multimeter to check for volt and ground on the crankshaft connector?
Yes, you can probe ground and reference on the crank sensor connector, using the battery terminals for the other meter probe. I don't have a wiring diagram for your vehicle, but my daughter's 2011 3i uses the exact same sensor, so the circuitry is likely similar for both. In my 3i wiring diagram, reference voltage comes directly from the ECM, so I can't tell if that pin is hot at KO or only hot at START, but you could check the connector pins with KO first. Then, if you don't see any reference voltage with KO, you can test again with a helper cranking it.

Ground is a fixed wire, so that pin should always read 0V, key in or out. Signal pin voltage reading of course is meaningless with the sensor connector removed. You could backprobe the (connected) sensor connector signal wire with your meter, but all you would likely see is a somewhat fluctuating 'average' voltage reading. As I wrote previously, you would need a scope to evaluate the signal waveform, and that's particularly important in you case because of the type of work you did (i.e flywheel).
 

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Discussion Starter · #12 ·
Yes, you can probe ground and reference on the crank sensor connector, using the battery terminals for the other meter probe. I don't have a wiring diagram for your vehicle, but my daughter's 2011 3i uses the exact same sensor, so the circuitry is likely similar for both. In my 3i wiring diagram, reference voltage comes directly from the ECM, so I can't tell if that pin is hot at KO or only hot at START, but you could check the connector pins with KO first. Then, if you don't see any reference voltage with KO, you can test again with a helper cranking it.

Ground is a fixed wire, so that pin should always read 0V, key in or out. Signal pin voltage reading of course is meaningless with the sensor connector removed. You could backprobe the (connected) sensor connector signal wire with your meter, but all you would likely see is a somewhat fluctuating 'average' voltage reading. As I wrote previously, you would need a scope to evaluate the signal waveform, and that's particularly important in you case because of the type of work you did (i.e flywheel).
Ok just for the record the crankshaft sensor is new and it was the same one that ran on the engine before pulled. Ok I will try my best to do all that lol.
 

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Ok just for the record the crankshaft sensor is new and it was the same one that ran on the engine before pulled. Ok I will try my best to do all that lol.
Checking the crank sensor signal in this case is primarily to confirm that all of the work you did related to the flywheel is all good, and not really expecting to find a bad sensor.

Yes it was, but I retimed everything including the camshafts.
Considering what you posted above, I suggest doing a compression test as well, along with or maybe even before doing the crank sensor testing.
 

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The cam and crank alignment tools where all in place before pulley removal and was reinstalled with an m6 bolt through the pulley into the timing cover? A no spark condition is commonly due to the pulley not being properly timed. The pcm sees that the crank and cam positions don’t correlate so it stops sparking
 

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Discussion Starter · #15 ·
Checking the crank sensor signal in this case is primarily to confirm that all of the work you did related to the flywheel is all good, and not really expecting to find a bad sensor.


Considering what you posted above, I suggest doing a compression test as well, along with or maybe even before doing the crank sensor testing.
Ok so just to clarify (sorry) I unplug the crankshaft sensor and put my multimeter on the positive prong and then ground out my negative prong on my multimeter to like a bolt or the engine. Then turn the key to the ON position and look at my multimeter to see if I have power there correct? Yes I will do a compression test as well.
 

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Discussion Starter · #16 ·
The cam and crank alignment tools where all in place before pulley removal and was reinstalled with an m6 bolt through the pulley into the timing cover? A no spark condition is commonly due to the pulley not being properly timed. The pcm sees that the crank and cam positions don’t correlate so it stops sparking
Yes, I’m gonna walk you threw the steps I did to time it. First I turned the pulley until the 1st cylinder was coming up to TDC then inserted the timing peg that goes behind the engine , then I turned the pulley until the 1st cylinder hit the timing peg (which then number 1 cylinder is at TDC) then I made sure the cam lobes were both pointing inwards to each other ( intake and exhaust) then I took off the pulley and then I got to the flywheel and turned the crankshaft until it hit the timing peg ( because when I take the crankshaft pulley bolt out it moves the crankshaft out of time) then I put the pulley back on to where the M6 screw fits in the hole in the pulley itself, then I put the pulley bolt back in to snug everything down, then I counted counterclockwise from the empty space in the pulley to the 20th tooth and then I lined up the crankshaft position sensor to the 20th tooth then tighten it down. Hopefully you can follow along with this lol
 

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Ok so just to clarify (sorry) I unplug the crankshaft sensor and put my multimeter on the positive prong and then ground out my negative prong on my multimeter to like a bolt or the engine. Then turn the key to the ON position and look at my multimeter to see if I have power there correct? Yes I will do a compression test as well.
What you posted is basically fine, except that you wrote 'prong' so I'm just making sure you're probing the connector slot with the meter, and not the crank sensor itself. You're probably going to need to put a piece of wire or unfolded paper clip into the connector slot, if your meter leads are the typically sized ones that don't fit in.
 

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Discussion Starter · #20 ·
What you posted is basically fine, except that you wrote 'prong' so I'm just making sure you're probing the connector slot with the meter, and not the crank sensor itself. You're probably going to need to put a piece of wire or unfolded paper clip into the connector slot, if your meter leads are the typically sized ones that don't fit in.
Would a paper clip read the same number as if there was no paper clip?
 
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