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Check that your PCM is getting signal from the CKP sensor. You should get +12v between pins B and C at the sensor with the key on. If that checks out, go to the PCM itself and unscrew the blue connector.
The CKP pins are blue12 (signal), 21 (ground), and 2 (+12v). Connect one multimeter lead to blue 12 and the other to a ground. Have someone start the car and see if you get voltage between 0-5v. If so, then your CKP circuit is good. If not, check for continuity between the sensor itself and the appropriate blue pin: A-->12, B-->21, C-->2.
I don't think a bad cam sensor will result in no spark, but you can also do the same with it. See the schematic below for reference. Note that it's for a blue/green harness; you said that yours is blue/red, though a 2004 PCM should be blue/green. Regardless, the pins are the same, just substitute red for green.
Edit: I'm getting all of this info from lt1swap.com. I highly recommend you take a look over there, he has put together a wealth of information.
Check that your PCM is getting signal from the CKP sensor. You should get +12v between pins B and C at the sensor with the key on. If that checks out, go to the PCM itself and unscrew the blue connector.
The CKP pins are blue12 (signal), 21 (ground), and 2 (+12v). Connect one multimeter lead to blue 12 and the other to a ground. Have someone start the car and see if you get voltage between 0-5v. If so, then your CKP circuit is good. If not, check for continuity between the sensor itself and the appropriate blue pin: A-->12, B-->21, C-->2.
I don't think a bad cam sensor will result in no spark, but you can also do the same with it. See the schematic below for reference. Note that it's for a blue/green harness; you said that yours is blue/red, though a 2004 PCM should be blue/green. Regardless, the pins are the same, just substitute red for green.
Edit: I'm getting all of this info from lt1swap.com. I highly recommend you take a look over there, he has put together a wealth of information.
Man I just checked the CKP over the weekend with a buddy of mine who is a GM master tech and has a turbo ls camaro. Cam and crank sensors are new and all getting good signal/power. My Map codes keep coming back though so I’m going to get a new pigtail to be safe.
What are the chances of the reluctor wheel itself being damaged on a stock bottom end 5.3? Only codes are the 2 Map codes that keep coming back and still no spark.
I know that you've replaced sensors. I'm saying you should check at the PCM to ensure a wire wasn't damaged or anything. If you're getting +12v at the sensor that's a good start. And if you've checked that there is a signal at the PCM then disregard. I can't remember whether it's possible to get to the PCM pins with the connectors attached or not; if not, you'll have to feed the CKP sensor +12v.
A damaged or misplaced wire or unseated pin could be the culprit - I had one injector pin that wasn't fully seated when I rewired mine. Thankfully it threw a code to point me in the right direction.
It's possible that the reluctor wheel is damaged. If it's not difficult to get to the oil pan, it's certainly worth a check. I'm running out of ideas otherwise.
I know that you've replaced sensors. I'm saying you should check at the PCM to ensure a wire wasn't damaged or anything. If you're getting +12v at the sensor that's a good start. And if you've checked that there is a signal at the PCM then disregard. I can't remember whether it's possible to get to the PCM pins with the connectors attached or not; if not, you'll have to feed the CKP sensor +12v.
A damaged or misplaced wire or unseated pin could be the culprit - I had one injector pin that wasn't fully seated when I rewired mine. Thankfully it threw a code to point me in the right direction.
It's possible that the reluctor wheel is damaged. If it's not difficult to get to the oil pan, it's certainly worth a check. I'm running out of ideas otherwise.
I appreciate the input! I did check both sensors and the wire pins at each connector which is why we’re stumped.
Just ordered Holley terminator X though. Not to throw the towel in but after giving it some thought it just made sense considering I will be keeping the car forever and would like to go turbo soon. Fingers crossed it’s not the reluctor lol
Would the reluctor not throw a code if it was damaged? I removed the sensor and peaked through and it didn’t seem obviously bent although of course I can’t see that much through the hole. I’d have to pull the engine to remove the pan.
Update: after nothing but issues the car finally started for the first time with the ls engine! Using Holley terminator X. Wasn’t showing rpm even after trying two new ac Delco cam and crank sensors. I was thinking I’d be pulling the engine out today for a bad reluctor wheel when I decided to try the cam and crank sensor from a crusty spare 5.3 I picked up and the ckp sensor did it. Fired right up. Woo hoo
Good to hear you got it up and running! Man that's frustrating as hell that it was a new sensor(s) that was the issue. Chuck that thing as far as you can into the nearest body of water you find.
04-13-2020, 03:18 PM
