Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hello I will help you with your question,
The computer uses the gap to calculate TDC #1 but it may mot be located there. When the engineers know where the gap is they can program the software to add or subtract rotation to calculate the position of the crankshaft and do not have to place the gap at exactly TDC. I would have to install the balancer and turn it to the mark then observe the timing reluctor to see if it is rising edge or falling edge of the gap is TDC.
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who is they, the dealership or the manufacturer?
if i understood correctly that the tooth marking either before or after the missing tooth.
what would happen if the crankshaft was turned 1 time? would the ignition be off/ not spark casuse of it?
The manufacturer, sorry for not being clear on that. The exact TDC point can be setup to use the start of the gap or the end of the gap depending on what the engineer wanted to make it.
If you are 180 out on the crank position compared to the cam it will still spark just not at the right time.
The gear causes the crank sensor to create a signal each time a tooth passes and the signal is sent to the engine computer which counts then to know when each piston is at the top of its travel and the computer will fire the coil when it determines the most power will be made in the cylinder depending on its other sensor input.
If you don't have spark you check the signal from the crank sensor to the PCM and see if it gets there. A scantool looking at RPM is a great way to do this.
IF you have RPM showing on the scan tool the computer should be signaling the coil to fire. If you have power to the coil it should fire when the computer tells it to.
The rest is mechanical having the chain connect the crank to the cam and keep them in time.
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OK, that may be the right place I have never checked I just line the chains up as shown in the procedure.
Do you have any way to see if you have signal from the crank sensor?
thanks forn the info, i took the timing chain covers off again reset the timing again. refitted the covers reassembled the sub-frame and started to check for the rpms, but thye engine started right up. i think what might have happened was the cams where on time but the crank was 1 tooth off/slack was on the nwrong side of the timing chain/away from the tensioner and the crankshaft mover 1tooth to pick up the slack.
apon reseting the time ans ensuring the chain was tensioned correctly i believe that fixed the problem of no spark. your help was very inforamtive and spot on. i wouldn't have bin able to fix the problem without the info you provided.
again many thanks i will be comming back when i have another problem.