Camshaft issues
10-19-2020, 11:43 PM
#1
Camshaft issues
2009 G37x sedan. Mechanic states that the compression test is reading 180 (in his opinion normal) yet the car turns over but does not fire. I Replaced, TCM/valve body, crankshaft sensor (passenger side bank),sent the ecu off to reprogram (yet did not fix the issue). The mechanic replaced the fuel pump and battery. He stated that after he replaced the fuel pump and battery he got it to start but it did not stay running. His conclusion is that the camshaft needs replaced. Anyone have any other ideas? Please help me. -Eddie
10-20-2020, 12:38 AM
#2
Registered Member
Not sure how he got it to start by replacing the battery and pump if you are missing spark. Does not go hand in hand. And if he did maybe it's the alternator assuming there is spark after all
I say maybe the camshaft sensor as well. If there is a problem with spark make sure are your grounds are good ,no corroded wires
I say maybe the camshaft sensor as well. If there is a problem with spark make sure are your grounds are good ,no corroded wires
10-20-2020, 10:32 AM
#3
For one, 180psi compression is right at the bare MINIMUM standard as per factory spec. Those readings should be anywhere between 242-341psi @200rpm. There also shouldn't be more than a 14psi difference between all six cylinders... however...
What was the original symptom? Code?
If, and I stress IF, after replacing a ton of unnecessary parts, the engine fired for a brief moment, then likely your issue is electrical- bad wire(s), poor ground connections, etc. Replacing expensive parts (TCM, fuel pump) has absolutely nothing to do with a "No Spark" condition- if that is indeed a verified problem.
Keep in mind that some of these engines were having problems with the encoder ring slipping on the camshaft sprockets. A quick inspection might rule that in/out. Then there's the oil gallery gasket issue.
You are looking at a very high repair bill- parts will not be cheap, but time and labor costs really add up. In the end, if you are intent on keeping the car it might be cheaper to just replace the engine. There are a ton of used, low mileage VQ37VHR's out there at reasonable costs.
Hopefully others with more knowledge in these engines can offer additional guidamce.
What was the original symptom? Code?
If, and I stress IF, after replacing a ton of unnecessary parts, the engine fired for a brief moment, then likely your issue is electrical- bad wire(s), poor ground connections, etc. Replacing expensive parts (TCM, fuel pump) has absolutely nothing to do with a "No Spark" condition- if that is indeed a verified problem.
Keep in mind that some of these engines were having problems with the encoder ring slipping on the camshaft sprockets. A quick inspection might rule that in/out. Then there's the oil gallery gasket issue.
You are looking at a very high repair bill- parts will not be cheap, but time and labor costs really add up. In the end, if you are intent on keeping the car it might be cheaper to just replace the engine. There are a ton of used, low mileage VQ37VHR's out there at reasonable costs.
Hopefully others with more knowledge in these engines can offer additional guidamce.
Last edited by ILM-NC G37S; 10-20-2020 at 10:39 AM.
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Mzb3d (11-07-2020)
11-07-2020, 11:46 AM
#4
Original codes
The original codes were P0725 and U1000 codes. That’s what brought me to the conclusion that it was either the TCM or ECU but neither of those attempts of fixing those items resulted in anything different than the current situation of cranking and no start.
For one, 180psi compression is right at the bare MINIMUM standard as per factory spec. Those readings should be anywhere between 242-341psi @200rpm. There also shouldn't be more than a 14psi difference between all six cylinders... however...
What was the original symptom? Code?
If, and I stress IF, after replacing a ton of unnecessary parts, the engine fired for a brief moment, then likely your issue is electrical- bad wire(s), poor ground connections, etc. Replacing expensive parts (TCM, fuel pump) has absolutely nothing to do with a "No Spark" condition- if that is indeed a verified problem.
Keep in mind that some of these engines were having problems with the encoder ring slipping on the camshaft sprockets. A quick inspection might rule that in/out. Then there's the oil gallery gasket issue.
You are looking at a very high repair bill- parts will not be cheap, but time and labor costs really add up. In the end, if you are intent on keeping the car it might be cheaper to just replace the engine. There are a ton of used, low mileage VQ37VHR's out there at reasonable costs.
Hopefully others with more knowledge in these engines can offer additional guidamce.
What was the original symptom? Code?
If, and I stress IF, after replacing a ton of unnecessary parts, the engine fired for a brief moment, then likely your issue is electrical- bad wire(s), poor ground connections, etc. Replacing expensive parts (TCM, fuel pump) has absolutely nothing to do with a "No Spark" condition- if that is indeed a verified problem.
Keep in mind that some of these engines were having problems with the encoder ring slipping on the camshaft sprockets. A quick inspection might rule that in/out. Then there's the oil gallery gasket issue.
You are looking at a very high repair bill- parts will not be cheap, but time and labor costs really add up. In the end, if you are intent on keeping the car it might be cheaper to just replace the engine. There are a ton of used, low mileage VQ37VHR's out there at reasonable costs.
Hopefully others with more knowledge in these engines can offer additional guidamce.
11-09-2020, 09:41 AM
#5
A U1000 code has the highest priority and must be resolved first.
This code is declared when the TCM can not transmit or receive signals on the CAN bus for 2 seconds or more when the ignition is on.
My first step would be to verify the CAN bus signal at the TCM with a scope. If you don't have a scope, then use an ohm meter to verify the wiring.
As for the cam needing to be replaced, if the compression test is ok, then more than likely so is the cam / VVEL system.
(By the way, this engine doesn't have an intake cam, as the VVEL system controls the valve opening/closing)
This code is declared when the TCM can not transmit or receive signals on the CAN bus for 2 seconds or more when the ignition is on.
My first step would be to verify the CAN bus signal at the TCM with a scope. If you don't have a scope, then use an ohm meter to verify the wiring.
As for the cam needing to be replaced, if the compression test is ok, then more than likely so is the cam / VVEL system.
(By the way, this engine doesn't have an intake cam, as the VVEL system controls the valve opening/closing)
The following users liked this post:
Mzb3d (11-09-2020)
11-09-2020, 07:48 PM
#6
Thank you
I replaced the TCM from a used transmission and it did not solve the crank/no start issue. I will attempt to test it with an OHM meter like you suggested. I am leaning towards it being a camshaft sensor hopefully. Thank you for replying.
A U1000 code has the highest priority and must be resolved first.
This code is declared when the TCM can not transmit or receive signals on the CAN bus for 2 seconds or more when the ignition is on.
My first step would be to verify the CAN bus signal at the TCM with a scope. If you don't have a scope, then use an ohm meter to verify the wiring.
As for the cam needing to be replaced, if the compression test is ok, then more than likely so is the cam / VVEL system.
(By the way, this engine doesn't have an intake cam, as the VVEL system controls the valve opening/closing)
This code is declared when the TCM can not transmit or receive signals on the CAN bus for 2 seconds or more when the ignition is on.
My first step would be to verify the CAN bus signal at the TCM with a scope. If you don't have a scope, then use an ohm meter to verify the wiring.
As for the cam needing to be replaced, if the compression test is ok, then more than likely so is the cam / VVEL system.
(By the way, this engine doesn't have an intake cam, as the VVEL system controls the valve opening/closing)
11-10-2020, 08:46 AM
#7
If the TCM was replaced with a used TCM, did it get reprogrammed to match the VIN on the ECU? Looking for an older thread with a member named 'Coop' and his car's work at Level10...Pat at Level10 states that why he couldn't offer the Core First option to the Valve Body/TCM mod.
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11-11-2020, 03:28 AM
#8
Infiniti
I contacted the closest Infiniti dealership (4-5 hours away) prior to replacing the TCM with a used TCM. Their mechanic stated that a used TCM would not need to be reprogrammed.
If the TCM was replaced with a used TCM, did it get reprogrammed to match the VIN on the ECU? Looking for an older thread with a member named 'Coop' and his car's work at Level10...Pat at Level10 states that why he couldn't offer the Core First option to the Valve Body/TCM mod.
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