No spark and no signal from ECM to coil

Tiny
JCUSHMAN
  • MEMBER
  • 2002 NISSAN ALTIMA
  • 3.5L
  • 6 CYL
  • 2WD
  • MANUAL
  • 210,000 MILES
I have replaced the camshaft position sensors, and the coil condenser as it was not looking too good. Checked the crankshaft sensor and it appears too good. Went one more step and replaced it with a known good one from a 2003 Pathfinder. Mine works fine in the Pathfinder. Still no spark in the car listed above.
Sunday, March 6th, 2022 AT 3:14 PM

8 Replies

Tiny
JCUSHMAN
  • MEMBER
  • 6 POSTS
Correction: I am getting a.2 volt signal out of the ECM to the coil. I didn't get to check the coil side of harness. Will check when I get off work.
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Monday, March 7th, 2022 AT 7:40 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Just to confirm what you are seeing; you have 12 volts or .2 volts coming from the ECM to the coils?

However, we also need to know if this was an issue prior to replacing the CMP and condenser?

I know you said you replaced them because they were not looking good but was that to address this issue or was it working beforehand?

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If it was working prior, then do you still have the old parts? If so, we need to swap them back in one at a time and see when the spark returns.

I assume you have 12 volts leaving the ECM so then we do need to know what is on the other end as you stated.

That is great that you have proven this is not a crank sensor but let's start with this and go from there.

Thanks
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Monday, March 7th, 2022 AT 3:48 PM
Tiny
JCUSHMAN
  • MEMBER
  • 6 POSTS
This is the issue that led me to change the sensors. I was being lazy and had them on hand, so I just swapped them instead of checking the sensors in the car. I have 12v supply at the coils from ECM. The.2 volts is the signal from the ECM to the power transistor. I got that reading on my multimeter as I do not own an oscilloscope.
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Monday, March 7th, 2022 AT 7:13 PM
Tiny
JCUSHMAN
  • MEMBER
  • 6 POSTS
I revoke my previous statement; there is no ECM signal to power transistors.
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Monday, March 7th, 2022 AT 8:56 PM
Tiny
JCUSHMAN
  • MEMBER
  • 6 POSTS
Also, I have confirmed 12v at each component fed from the ECM relay.
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Monday, March 7th, 2022 AT 8:57 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
So, if you have no power to the coil on the transistor circuit then this is either due to no crank signal or the ECM is faulty.

The only thing that gives me pause is that ECM circuits to each coil are separate circuits. So that tells me it is not getting the crank signal. Clearly it is not the sensor so we could have a circuit issue.

So, if you don't have a scope to watch the pattern, we need to get a little more info on how this happened.

What is the history on this one? Did this just start one day or has this vehicle been sitting?

We could have a tone wheel issue or a wiring issue which a scope would show that but hopefully we can get more info on this to point us in that direction.

Thanks
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Tuesday, March 8th, 2022 AT 4:13 AM
Tiny
JCUSHMAN
  • MEMBER
  • 6 POSTS
Somehow the vehicle runs fine with either CKP sensor but not the Altima. Purchased a new sensor today and Houston we have ignition. Tachometer is a little twitchy though. So, it could be a bad connection which may have been the problem all along.
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Tuesday, March 8th, 2022 AT 5:05 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Very interesting. A connection issue would make perfect sense because if it is not then that is one of those odd issues that is hard to explain.

Thanks for coming back to update us. I am sure that info will help others.
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Tuesday, March 8th, 2022 AT 5:11 PM

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