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OK so I just finished the OPS replacement and thanks to everyone for the help. I also took advice and relocated the OPS to the passenger side and while in there replaced the secondary air check as well as the MAP sensor since it was all behind the intake. I was told if the CMP wasn't leaking leave it alone also I couldn't find the part to order it. I put everything together including a new PCV hose that was broken and brittle, and it went well. I was feeling good.. until starting the damn car!! Not only was it hard to start I had to crank it 3 time it now is throwing codes and the check engine light is on. The codes are as follows and any help on why all of the sudden I have these codes would be great.
The P0342 is CMP related...you may have pinched one of the 3 wires on the CMP sensor or it may not be plugged in properly if you had unplugged it...a CMP signal is not needed to start the car (you only need the crank sensor) and a long crank time is associated with a defective CMP sensor....the other codes are EBCM related....I don't recognize the 0844 and 1664...I'd clear the codes, make sure the battery is FULLY charged (12.66 volts) and try starting and see what DTC's come back before shutting the car off...were the DTC's read through the DIC or scan tool ??
You double checked all the wiring and moved it all out of the way when reinstalling the intake, right? those driver side harness & wires like to make its way back under and you may have pinched a wire.
I was careful putting it back in but I guess it is possible although the CMP sensor (or whatever the one at the back is called) has wiring leading down the back so it shouldn't have creeped back up the block. I never unplugged it because I wasn't replacing it.
I am having trouble finding the CPS for the 1997 Corvette. Does anyone know the exact part number? If I am going to have to take it apart again to check the wires I am going to replace it.
I would make a suggestion if you do change the CMP sensor you not only check the wires visually but do a signal integrity check...12 volts, ref. ground and the signal...also with those “U” codes I’d check the EBCM power and grounds first before even thinking about replacing it...your ‘97’s EBCM is located at the rear end so I don’t think the wiring could have been affected where you were working !!
I hope this helps you
On your 97 there is supposed to be two grounds G401 og G402 .
As far as I know the G402 is located on the frame but on the opposite side(right) of the car compared to the G401 location .
Have you disconnected the battery, If you fixed the PCV system it will run like crap until you reset the computer by disconnecting the battery for a few minutes. I experienced this when I fixed mine. Scared the hell out of me, I just knew I tore something up. Good luck.
I will check all of the wiring I can but I am far from wanting to begin diagnosing an entire wiring system on a Corvette. I already unplugged the battery for 24 hours so any codes should have reset. I ordered what I think is the correct CMP so when it comes in I will pull the intake again (should go faster this time) and replace it as well as the wiring at the connector. ground is easy full volt is easy but the lower voltage is code so i need to find out what the sensor voltage is .5 volt?
I will check all of the wiring I can but I am far from wanting to begin diagnosing an entire wiring system on a Corvette. I already unplugged the battery for 24 hours so any codes should have reset. I ordered what I think is the correct CMP so when it comes in I will pull the intake again (should go faster this time) and replace it as well as the wiring at the connector. ground is easy full volt is easy but the lower voltage is code so i need to find out what the sensor voltage is .5 volt?
The CMP sensor has NO .5 volt !!...it is a 3 wire Hall Effect Sensor...the RED is your 12 volt feed, the PINK/BLACK is your ref. ground (ground) and the BROWN/WHITE is the sensor signal (to PCM)...there is a way to test the sensor before installing...don't know if you want to try that BEFORE you button it back up !!...you can also check the sensor wiring at the PCM before even removing the sensor and manifold with a voltmeter but you won't see the normal 0-12 volt signal...you might only see 3-5 volts with a DVOM !!
The P0342 is CMP related...you may have pinched one of the 3 wires on the CMP sensor or it may not be plugged in properly if you had unplugged it...a CMP signal is not needed to start the car (you only need the crank sensor) and a long crank time is associated with a defective CMP sensor....the other codes are EBCM related....I don't recognize the 0844 and 1664...I'd clear the codes, make sure the battery is FULLY charged (12.66 volts) and try starting and see what DTC's come back before shutting the car off...were the DTC's read through the DIC or scan tool ??
So as a question you said the CMP is a back up but as long as the code is causing the check engine light the car wont start. If I clear the CMP code the car starts right up but then the code comes back while running, almost instantly.If the crank sensor (which I think is located behind the starter) is the primary why wont it start?
Hi !!….if you have a voltmeter we can try this to see if you have a crank signal during start....back probe as pictured and connect red lead of voltmeter to pin 62 (light green wire) at the C2 connector...PCM pins are numbered !!...connect black lead to good ground....crank the engine and you should see something similar to my video of cranking over my engine with a good crank sensor...you should see similar voltages !!...if no voltage the CKP wiring and sensor will need to be checked !!
OK well I didn't get as far as testing the crank sensor yet because when I pulled the intake and checked the CPS I had somehow pulled the wires slightly back in the plug, so it wasn't making contact. My mistake as I thought I had given it plenty of room while moving it around but it must have happened while I was sliding it back in or maybe while I was connecting the hose that leads to the brake booster. Also the new CPS I ordered came in wrong the plug would have been even tighter as it was oriented 180 degrees off from OEM. It seems to get harder and harder to find the right parts for this car.
OPS complete.. now codes everywhere!!!
until starting the damn car!! 
Not only was it hard to start I had to crank it 3 time it now is throwing codes and the check engine light is on. The codes are as follows and any help on why all of the sudden I have these codes would be great.
