blkdrgn613

ok, so here goes.

problem is as follows..

on cold start, the car losses all power on accel around the 1500 rpm mark, the car jerks and lurches with no accel. let the car warm up for 15 min, runs fine. sometimes while driving the initial problems shows up, where i get zero power on accel but i can floor it and it jumps above 2k rpm and accels but jerks around at the 1500 mark.

camshaft position sensor bank 1 (p0340).

bought a new sensor, put it in, fairly easy and straight forward.

car wont start.

unplug the sensor, car starts after 3-4 secs and runs but p0340 pops up almost immediately.

after searching and searching, the only thing i could find is that i need to be at comp TDC before replacing the sensor.

removing the timing cover is not an option as it is just me and i dont have the tools or time (kids need to be picked up from school, wife work, etc.) to accomplish this.

how can i get to TDC without taking the engine apart?

ATL

if u remove the spark plug and turn the motor over slowly by hand u can find tdc

what brand sensor did u buy and install?

blkdrgn613

standard motor products.

removing plug 1 is a pain.. how will i know if i have comp or ex tdc?

DennisMik

iTrader: (2)

Remove the spark plug and hold something in the spark plug hole to plug it as you rotate the crankshaft. If the piston is coming up on the compression stroke, the pressure will blow the blockage out. Then use the timing markings on the harmonic balancer to set TDC.

Knowing that cylinder #1 is a pita, you can use cylinder #4. The firing order of the engine is 1-2-3-4-5-6. Cylinders 1 and 4 have their pistons moving up and down in sync, the only difference is when cyl #1 is coming up on the compression stroke, cyl #4 is coming up on exhaust and visa versa. So if you use Cyl #4, when you feel it coming up on compression, go one more turn of the crankshft, again using the timing marks on the harmonic balancer.

TunerMaxima3000

iTrader: (4)

It shouldn't matter where the engine position is when you replace the sensor, that makes no sense. Forget that idea, trust me, that's not your problem.

Did you do the FSM diagnostics for the P0340? Or did you just replace the sensor and that's it?

http://www.nicoclub.com/FSM/maxima/2003/ec.pdf

Start on Page 322.

blkdrgn613

i followed the fsm from start to finish and everything with the p0340 checked out. my issue still remains. i DO have a timing chain rattle, but can neithor afford to have a mechanic fix it or do it myself.

used to pop p0011, but now all i get is the p0340.

what i cant understand is, if i dont need to be at TDC, then why cant i start the car with the new sensor? this is the second sensor that i have tried. the first was a beck/arnley from autozone, when i put that one in the car acted as if i unplugged the MAF. (which i happen to know from cleaning it a few months ago and didnt reconnect it properly at first)

L_U_D_I_AMaxima

iTrader: (3)

I would suggest starting with an OEM sensor and then take it from there... this is a vital part to the engine so you need a quality reliable part

TunerMaxima3000

iTrader: (4)

If your timing is off more than 4* (unsure of the exact amount, 4* is a rough guess), then the car won't start as a safety precaution to save the engine from blowing up.

If the timing IS physically off, then this is the reason, and you need to do those tensioners/chain, period. You will destory that engine if you don't, it's a lot cheaper to fix what you ahve then buy something new, ever heard of pay me now or pay me later? lol. Just food for thought!

As for your second question:

-The Camshaft sensor(s) is used to start the car, that's it. The ECM checks in with the sensor off and on after startup but these are primarily diagnostic checks. Once started the Cam sensor is not a priority signal.
The Engine checks RPM at the crank vs. Cam to locate TDC and fire the proper injector to start the car quicker and smoother.
Again, if it sees something that doesn't make sense when comparing the Crank and Cam locations, it won't start as a safety, and will throw a code.

-The Crankshaft sensor is used to run the car. Once the ECM knows TDC location it doesn't need to watch the camshaft to do it's job, it just runs off the crank.

-What is happening to you is the ECM doesn't like the CAM sensor it gets when the Cam sensor is hooked up.
When Unplugged, it reads "OPEN" and runs in a default mode. This starts the car off ONLY the Crank Sensor. It takes longer to find TDC and get the engine running this way, but it will start eventually. This is why it will start with the Cam sensor unplugged, but will be hard to start/long cranking.

Hope that made sense!

TunerMaxima3000

iTrader: (4)

The fact that it wont run with the sensor in place tells me that the timing is probably PHYSICALLY off, and needs immediate attention. This isn't for certain, but it does sound likely in your case depending on the mileage, what IS the mileage?

RR5

iTrader: (6)

Did you consult the fsm?

TunerMaxima3000

iTrader: (4)

Though I am sure that the FSM leads the last portion of the diagnostic as "Inspect/Repair Timing Chain & Tensioners", which isn't exactly a "it all checks out" at all

boatboy63

This sounds like a similar issue I am having with my 02. I posted a thread about it at http://forums.maxima.org/5th-generat...ont-start.html

Just changed the sensor in mine due to P0345 but was not aware of the TDC issue. Have tried starting since and have been unable. My question now is since I installed it and have cranked it, do I simply put it on compression TDC for #1 and this will get it calibrated? What about next time when it cranks over...it won't be on TDC again.

TunerMaxima3000

iTrader: (4)

Did you read this thread? I mentioned a few posts up that whatever "install at TDC" thing you guys are talking about is IMO complete shenanigans, no idea where that came from.

blkdrgn613

diagnostics for p0340 do not involve inspecting the timing chain.

the entire work flow for inspecting p0340 is completed with no issues with any associated parts.

its possible that i received a bad part and have started the return process for it.

i don't know why the car is throwing the 340 tho.

with the sensor connected or in default mode, i still have the power loss/jolting happening on a cold start. a friend suggested i look at the MAF.

i pulled the sensor out and gave it a cleaning with MAF cleaner and the problem seemed to go away, until the car sat for a few hours and got cold again.

then had the same issue.

the same problem also happens randomly while driving, causing me to pull over and turn the car off for a few seconds and start again, sometimes needing to do this a few times for it to accel properly.

a quick search showed me about 500-600 for a MAF sensor, but its for the full housing and everything. is there anyplace i can get just the sensor itself?

blkdrgn613

took a video of the issue so it could be better understood.

i held the camera against the steering column so any jolts and jitters would be felt.

each press is steady and held, no flooring it.

TunerMaxima3000

iTrader: (4)

MAFS methinks for that problem, but I'd chase the codes you have before you chase other stuff

TunerMaxima3000

iTrader: (4)

Step #11 is inspect camshaft. But you're right, there's no actual timing check there, which is silly, isn't it?

foodmanry

iTrader: (15)

Man...I have seen more issues on this board due to aftermarket parts replacements like these sensors, ignition coils, MAF's. It only leads you to troubleshoot to the point of replacing the sensor with OEM and BAM it works just fine.

I replaced both crankshaft position sensors on my 2K Maxima about 8 months ago and no issues. The TDC thing is totally shenanigans as Tuner stated.

Stop over thinking this problem before you replace it with an OEM sensor. Even if you get it to work with the aftermarket sensor it will likely fail before an OEM sensor so it is a waste of money any way you look at it.

TunerMaxima3000

iTrader: (4)

^That's good advice right thur.

OEM isn't even that much more, Courtesy Nissan, etc. IMO, it's worth getting something that will go another 100,000 miles or more, rather than buying an Ebay/Joes part store gamble.

I've been dealing with Phil at GRUBBS Nissan now since Dave is Gone. He is AWESOME, supreme replacement for Dave.

I deal with him via. G35driver.com though, not sure if he's on here. Here's Gdriver profile http://g35driver.com/forums/members/...il-grubbs.html

blkdrgn613

update to my issue.. i went to move my car tonight, dead cold.. major major issues when doing that, but i stalled 4 times, hard to start after the first stall.. but, i had the bright idea to check the codes, and i got a p0731 on top of my p0340. so it seems that i may have more than just a timing issue. i dont know if maybe i popped the 1st gear code just because the timing is off or im running richer than i should, but i thought it was worth mentioning.

as for everything else, nothing can be doen yet as i need $2k to fix the timing issues. so i may as well havbe the tranny looked at while they have it out of the car.

TunerMaxima3000

iTrader: (4)

Please post the OEM description of the Code you get.
I'm not lazy, but I'm not going to go digging for every code's description every time someone posts, it's relevent

Not being a ****, just constructive advice