This afternoon I was at the store. Came out and started the car as normal 2001 zo6 stock with 45k. I went to pull away and the car died like I had turned off the key, I thought I had actually stalled it(manual). I attempted a restart and it was now a crank no start. I got out and checked the fuel rail which has plenty of pressure so it isn’t a fuel pressure issue I don’t believe(car shut off like it lost spark). I have no codes on the dic and when I hooked up with my scanner no codes and no pending. The security system seems to be working appropriately, no flashing security light or security light lit up. I pulled up live data and found that I have no rpm when cranking(I assume I would see rpm data while cranking) and my tach doesn’t move either. From my quick research it looks like the crank sensors fail like this, no code and will cause a no start or die while driving. I will pull my oil fill to make sure that my valve train is moving( timing chain didn’t break) and check power and ground at the sensor but I don’t have a scope to look at signal. Is there anything I’m missing after I confirm those things before I order the oem sensor? Anyone know how difficult a job it is on jack stands? Looks like I need to pull the starter off atleast.

 

Yes, starter needs to come off...with a bad CKP you will also have no injector pulse...you can check that to be certain it’s the sensor...you should check the wiring just to make sure it’s not a wiring issue !!

 

Thanks c5diag. I don’t have a noid light but I should be able to backprobe an injector and use a test light on it will cranking?

 

Yes, you’d connect your test light to battery positive... injector circuit is ground side switched...test light will be fairly dim while cranking !!

 

I’ll give it a go. Thanks.

 

Quick update. I was able to get the sensor out last night. WOW, what a bad spot. Had to unbolt the midpipe from the headers in order to get clearance to slip the long starter bolt
out. Someone had replaced all of the exhaust bolts except one for some reason. Of course it is the one closest to the motor and no real good way to get a torch in there working off of jack stands. So that snapped off. I checked power and ground on the sensor wire with the test light and had both. I made the reasonable conclusion that no rpm signal and power/ ground at sensor that the sensor just died. So I order a ac Delco oem from Rockauto. The next thing is to figure out what to do about the broken stud. If I unbolted the headers I could slip them out and fix the stud but I am afraid of those header bolts snapping. Are those common to snap off? I would rather just pay someone to put it up on the lift and have them drop the midpipe and pull the stud if there is risk of having an issue with header bolts snapping.

 

I got the new AC DELCO sensor yesterday but haven’t had time to put it in. I did pull the headers on that side off so I could fix the manifold bolt so I have good access down there now. I figured since I have good access now that I would check the voltage on the 12
volt source wire rather then just probing with a test light. I found that the 12 volt source had 10.4 volts on it when using both the ground in the connector and using the negative post on the battery so I know I don’t have a voltage drop issue because of a bad ground on the circuit wire. I check battery voltage at battery and have 11.7. I checked voltage at the o2 sensor there and found it to be at 11.4 so much closer to battery voltage. Is there a problem on the circuit before I go ahead and put the new sensor in and starter back up or is lower than battery voltage normal? I planned to hook the sensor back up, put the starter back in and then hook up the scAnner and check for rpm count while cranking in clear flood mode.

 

So you are checking the light green wire at the CKP sensor ??...if you only see 10.4 volts there I would go the the PCM and back probe the circuit and see if you see 10.4 or battery voltage there...it is on pin 2 of the C1 connector...if you see battery voltage there you have some resistance between the PCM and sensor...I use piercing probes and see where in the wiring the 12 volts returns...if also 10.4 volts at the PCM check the cam sensor 12 volt supply at pin 39 on the C2 connector...it is a Red wire. The 12 volt supply for both the cam and crank sensor are shared internally inside the PCM !!...had a member who had like 3 volts at both sensors and it was a shorted cam sensor...I had him remove the cam sensor connector and the 12 volt supply returned on both sensors...go figure !!

 

Good news, I was able to put some time in today. I unplugged the cam sensor and no change in 10.4 volts at sensor. I was afraid to pull the plastic covers off of the pcm plugs because of age if I didn’t have to. So I went ahead and installed new sensor and put the starter in and torqued it to spec. The battery was low on voltage( likely from the hood light coming on so many times without a battery charge as well as my troubleshooting early on with cranking). So the battery was to low to turn the motor over. I put it on the charger and let it charge for the afternoon. I just pulled up live data and took a look at rpm while cranking in clear flood. The Rpm registered around 150
after about a second of cranking. So that has come back because I had 0 displayed no matter how long I cranked before. So now I wait for a new manifold gasket, manifold bolts and lower manifold to y pipe bolt that I snapped which will be here next week. I’ll follow up next week when I get it all buttoned back up and close out this issue. Thank you for your help! You have been invaluable!

 

I had some time tonight to throw everything back together and the car started right up as anticipated by the rpm count coming back alive while doing a the clear flood crank. Thanks for the help.