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09-26-2018, 02:30 PM
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Firstly, this sub-forum is not for car questions as per the header description, I'll try to get your thread moved to the appropriate sub-forums but it might be deleted entirely during the process.
Engine fail to crank can be a number of things.
First and foremost you need the proper voltage and proper AMPERAGE to crank, I would put your battery on a charger just to verify it's actually FULLY charged. New batteries discharge over time and a seller is not SUPPOSED to sell a brand new battery that has lost it's initial charge, a seller may NOT charge a battery that has been sitting on the shelf, if it has lost it's initial charge it must be sold as a "blemished" battery.
Next most important is the power delivery to the chassis, the battery cables, they must be clean of corrosion and be properly clamped to the battery and chassis, this means BOTH ENDS of the battery cable, in the case of the G35 with a bolted fusible link there are 4 connections on the positive side of the battery, the battery post itself, the 2 connections on the fusible link, and the other end of the positive cable at the starter. There are also numerous chassis grounds that need to be clean and properly bolted, a jumper between the chassis under the coolant reservoir and the timing cover is critical for the engine to start.
Next is overcurrent protection of the circuit, fortunately this is very straightforward on the G35, a fusible link is bolted directly to the positive battery terminal and there are clear viewing windows for each of the fuses, typically a visible inspection is all that's needed but you could also take a digital multimeter and ring out the circuitry to ensure there is a complete circuit through it, normally when they blow the viewing windows either turn completely black from the arc or you can see the melted wire of the fuse.
As long as power is properly distributed to the various systems of the vehicle, the ECU, the BCM, and the starter the next point to inspect would be the Nissan Anti-Theft System or NATS, there is a transponder chip inside your key (or i-key fob in the case of an intelligent key system push-button start), The BCM reads the transponder ID through a small antenna bolted to the side of the key lock cylinder and if it's an ID it recognizes then it sends a PASS signal to the ECU when you turn the key to ON. Next the ECU looks for the crank position sensor (CKP) to ensure there is a complete circuit (no data because the engine is not turning, just looks to make sure one is plugged in), if it finds a CKP and you turn the key to START the ECU closes the relays inside the Intelligent Power Distribution Module (IPDM, fuse box behind the battery) for the fuel pump and the starter. The fuel pump primes in the system, the starter cranks the motor, while cranking the ECU measures data from the CKP as well as ALL cam phase sensors (CMP, non-revup models have 2 while the rev-up models have 4 CMP). The ECU then uses the CKP and CMP data to determine when exactly to open fuel injectors and deliver spark via the coil packs. If everything is working properly the engine will have proper combustion and start running.
If your engine WONT CRANK the proper work flow is.
-Check battery
-Check battery cables
-Check fusible link
-Check start relay
-Bench test starter itself
Depending on how much other information I have about a vehicle I will typically get the vehicle lifted up and take a test light probe or digital multimeter and read the signal side of the starter while someone else turns the key to START to see if there's any power being sent to the starter solenoid. If there's power then check the primary starter cable, if it too has power then pull the starter and bench test it because it's likely fried.
If NATS does not recognize your key when you turn the ignition to ON the system indicator light will turn SOLID RED.
Engine fail to crank can be a number of things.
First and foremost you need the proper voltage and proper AMPERAGE to crank, I would put your battery on a charger just to verify it's actually FULLY charged. New batteries discharge over time and a seller is not SUPPOSED to sell a brand new battery that has lost it's initial charge, a seller may NOT charge a battery that has been sitting on the shelf, if it has lost it's initial charge it must be sold as a "blemished" battery.
Next most important is the power delivery to the chassis, the battery cables, they must be clean of corrosion and be properly clamped to the battery and chassis, this means BOTH ENDS of the battery cable, in the case of the G35 with a bolted fusible link there are 4 connections on the positive side of the battery, the battery post itself, the 2 connections on the fusible link, and the other end of the positive cable at the starter. There are also numerous chassis grounds that need to be clean and properly bolted, a jumper between the chassis under the coolant reservoir and the timing cover is critical for the engine to start.
Next is overcurrent protection of the circuit, fortunately this is very straightforward on the G35, a fusible link is bolted directly to the positive battery terminal and there are clear viewing windows for each of the fuses, typically a visible inspection is all that's needed but you could also take a digital multimeter and ring out the circuitry to ensure there is a complete circuit through it, normally when they blow the viewing windows either turn completely black from the arc or you can see the melted wire of the fuse.
As long as power is properly distributed to the various systems of the vehicle, the ECU, the BCM, and the starter the next point to inspect would be the Nissan Anti-Theft System or NATS, there is a transponder chip inside your key (or i-key fob in the case of an intelligent key system push-button start), The BCM reads the transponder ID through a small antenna bolted to the side of the key lock cylinder and if it's an ID it recognizes then it sends a PASS signal to the ECU when you turn the key to ON. Next the ECU looks for the crank position sensor (CKP) to ensure there is a complete circuit (no data because the engine is not turning, just looks to make sure one is plugged in), if it finds a CKP and you turn the key to START the ECU closes the relays inside the Intelligent Power Distribution Module (IPDM, fuse box behind the battery) for the fuel pump and the starter. The fuel pump primes in the system, the starter cranks the motor, while cranking the ECU measures data from the CKP as well as ALL cam phase sensors (CMP, non-revup models have 2 while the rev-up models have 4 CMP). The ECU then uses the CKP and CMP data to determine when exactly to open fuel injectors and deliver spark via the coil packs. If everything is working properly the engine will have proper combustion and start running.
If your engine WONT CRANK the proper work flow is.
-Check battery
-Check battery cables
-Check fusible link
-Check start relay
-Bench test starter itself
Depending on how much other information I have about a vehicle I will typically get the vehicle lifted up and take a test light probe or digital multimeter and read the signal side of the starter while someone else turns the key to START to see if there's any power being sent to the starter solenoid. If there's power then check the primary starter cable, if it too has power then pull the starter and bench test it because it's likely fried.
If NATS does not recognize your key when you turn the ignition to ON the system indicator light will turn SOLID RED.
Last edited by cleric670; 09-26-2018 at 02:50 PM.
#3
09-26-2018, 06:02 PM
Originally Posted by cleric670@gmail
I'll try to get your thread moved to the appropriate sub-forums but it might be deleted entirely during the process.
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Blue Dream (09-29-2018)
#4
09-27-2018, 12:40 PM
#5
09-27-2018, 03:23 PM
Join Date: May 2017
Location: Washington State
Posts: 14,790
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The following users liked this post:
Blue Dream (09-29-2018)
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09-27-2018, 03:51 PM
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09-27-2018, 04:03 PM
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