camshaft sensor bad?
 

what are symptoms of bad camshaft sensor?

car starts up in mornings fine, then during day it randomly starts fine or not. when it does not start fine i can hear noise starting up but it does not start up on first try. then on second try it starts up fine.

it annoys me, so i am trying to figure out if it is camshaft sensor or fuel pump going bad?

alt and starter are new, battery is new too.

thanks for help!

bump up?

I doubt you have a bad camshaft position sensor (CPS). I believe they are used to detect a misfire, but dont quote me on that. You can check whether the camshaft sensor is working fine. IF u have a multimeter or ohmmeter, u can check the impedance as per the spec in the FSM or the Haynes. If the resisitivity matches up then the CPS is fine.

Usually, when u have startup issues, AND no other drivabliluty engine issues, its more of a crankshaft position sensor (CKPS) REF issue.

There are two CKPS, POS and REF. POS is located in the front bottom of the engine. REF is located in the rear of the engine near the transmission housing / engine interface.

Usually the CKPS REF is fouled and dirty and causes strartup issues. Its is attached with one 10mm bolt. Remove the sensor and check for fouling. If dirty, wipe it off wit a rag. DO NOT SCRAPE IT. sometimes wiping doesnt work and jus need to replace it. ITs like 80 bucks from autozone. I kno cuz i jus replaced mine 2 wks ago. Starts up like a champ now.

U can do a voltage test but on the CKPS, i think, but u need someone to crank the engine while u read the voltmeter.

what do u mean? does the car crank longer than usual?

If u let the car keep cranking will it eventually fire up?

Does it feel like the flywheel or crankshaft is rotating and the CKPS is looking for the "sweet spot" to tell the ECU to start the car.

If so, yeah replace the CKPS REF.

Thats what happens to me, it takes longer time to crack up, i just let it cranking up till it starts up. it happens randomly. like for example in korning after it sits all night it starts up perfectly, then during day it could happen on 2nd or 3rd start up, then 1-2 times it is fine, then on 2 to 4th start up it takes longer time.

are you sure it is CKPS REF? if yes please forgive me, please explain what is exactly CKPS REF and where it is located? how much it costs?

Here is FSM, factory service manual. It will show u better than i can explain where it is. And honestly, its the only sensor in that location. So u cant miss it.

http://www.nicoclub.com/FSM/maxima/

Lay on the ground by the driver side front tire, look at the tranny housing towards the eninge and its the only sensor there under the car.

It def sounds like a CKPS REF issue.

THe crankshaft position sensor is a magnet that "senses" the position of the crankshaft and thereby "senses" when the engine cylinder #1 is at top dead center, TDC. WHen the engine is at TDC, the ECU, electronic control unit, tells the fuel pump to supply fuel and start the car. Without the CKPS, the ECU will not know to supply fuel to the engine.

In your case, the CKPS cant find TDC on the crankshaft cuz the CKPS is covered with dirt and metal shavings. If its covered with crap jus replace it.

Once u locate it will take 2 secs to remove and inspect. Removing it and inspecting it will not harm anything. If its clean then re-install.

great, please tell me exact name of CKPS REF sensor so i can order it online. that link you gave me is not good, can you give me specific link so i can see it and print out for my mechanic to do it for me, since he is not good with sensors, he is more into mechanical side of work.

Here is the link again.

http://www.nicoclub.com/FSM/maxima/

Dont buy online, jus go to autozone and buy it. But if u gonna go to a mech have him test it first. If ur mech cant troubleshoot a CKPS then u shd go to another mech.

Do a SEARCH, there are FSM pics in some of the threads of the CKPS.

I prefer Nissan parts since they proved to be long term durable compared to non nissan sensors. so whats exact name or part number for me to order online?

thanks!

idk what the part number is. I bought mine from AZ. ITs jus a sensor and AZ is proven to have good stuff. Its your choice tho....

autozone has "some" original nissan parts and they cost less than here:
http://www.courtesyparts.com/maxima-...1814_1816.html
and part # 23731TA
good luck

Yeah thats the right part.

I paid like 80 bucks for mine from AZ. No lifetime warranty from AZ cuz its electrical, but the dealer or online wont give u a lifetime warranty either....

TEST THE PARTS 1st save your money it has happen too many times people just shoot the money gun at it replacing parts all willy nilly and you cant return electrical parts including sensors and if its dirty i would clean it and reinstall and see if it comes back

and if your testing the crank sensor thats in front its really easy to take out and test one 10mm bolt and you side it out done

but its your money do what you will