Summary of no start/hard start??

[jacjm]

just got home--wow, i made it almost 116 miles before the ses light showed. this time, it is P0172 system rich, bank 1.
also tried to put gas in, again, -no go. 6 gallons tops. i KNOW the vent control valve works.
i can understand the reasoning behind the sensors not getting enough voltage, AND, that it could be any random sensor. BUT, 14.6 volts at idle ?? (that just seems like it would be high, to me). i will definitely check all the connections, tho. do you think a loose belt could cause low alternator output ?? i put a new gatorback on a little while ago, and snugged it up pretty good, (no, i didn't measure deflection) but now i sometimes have the screeching thing going on. maybe that IS the alternator, taking its last breaths. it is a shame i don't have more time, because EVERYTHING HAPPENS AT THE WORST POSSIBLE TIME!! (i was laid off all summer). any thoughts on the not-taking-gas problem??

[jacjm]

forgot to mention- it has been starting better and better. when it runs good, it is (almost) a joy to drive. i say almost because i am always waiting for something else to act up.

[i68k]

check the fsm for your vehicle specifications, you shouldnt be under 14V. not to say there isnt other things going wrong here.

it is possible the belt is loose, you should have a manual adjustment for your belt, did you try tightening your belt so its more snug. the gatorback belts dont usually slip or make noise. so if your screeching, something is loose, or bad pulley or something. maybe your alternator pulley is loose or it locked up.

the not taking gas is one of your evap sensors, it says in the fsm the name of the sensor, its not always the vent valve thats the problem, theres purge valves, vacuum cut valves, etc. folllow the fsm for your diagnostics, theres not much to it when you cant fill the fuel. maybe the fuel level sensor on the pump assembly is stuck. normally the vent valve is the cause tho.

[jacjm]

well, i must've brought myself more bad luck,,,it took 45 minutes, and had to have a jump, to get started after work.
i haven't located the fsm, yet. when i get more time, i am going to tighten the belt(s), the electrical connections to the alternator. and see if i can isolate the screeching. i am not so worried about the gas filling, yet, but it figures whatever is causing the problem is not the usual, common problem everyone else has found. i still have all the other garbage sensors that came with the used vapor box to benchtest and replace. i HAVE to find out what is the starting problem.

[i68k]

if you had to get a jump to get it started, your battery probably isnt supplying adequate amperage to turnover the motor fast enough, this would be your huge starting problem. do you have a new battery? you have to question why the battery would be bad, but we already know your charging system wasnt fully charging the battery. the battery maybe bad since it wasnt fully charging while you are driving (your low voltage), the amperage is probably low, which is power to turnover the motor. if your battery is new, it needs to be charged, because your charging system isnt working at its full potential. it seems this is only half your problem, but i would change all 3 components by now (battery, alternator, belts), and see how you make out, making yourself fresh grounds. if your belt is new, you can reuse it, just make sure its tight, you can use the specs in the fsm. like said earlier, other random electronic sensors may lose voltage and could possible not operate correctly, or prevent normal operation of the vehicle. i would deal with your fuel filling issue after this massive electrical situation you have going on, its possible sensors/valves are not moving/resetting so you can fill the fuel.

EDIT: just fyi, if you dont fix your grounds and charging system, you could potential ruin other electronic parts on the car, eventually leading to a fried ecu if the problem doesnt get addressed soon.

you can download a fsm for free
try these:
nicoclub.com/fsm
allsentra.com/fsm

[jacjm]

the motor turns over plenty fast enough, and is always "just about" to start. after 45 minutes of off-and-on trying, i would expect a new battery to die, too. to finally get it started, i cleared the system rich code, and it started not long after that. this AM, it started right up (still had screeching). then went to work (about 60 miles) and no SES light. this evening, left work and it started right up with zero screeching. drove home and no SES light at all. it drove like (almost) new. i stopped to put in more gas (again) and this time it took almost 9 gallons, with no gurgling. then, it cranked over more than a "good" running car should, to start, but it did start. i am not worried about the gassing problem right now, but this car has been throwing me so many curve balls, i am completely baffled. hence, the reason why i am on here.
when i say it started right up, i mean to convey that i just barely tap the key to the start position. my g/f's titan starts perfect every time, and you just barely tap the key to start, and everything works as designed. this sentra does it occasionally, and other times (rarely, has happened 2 or 3 times in 8 or 9 months) it may not start at all, before the battery dies.
i do not have the time right now for a thorough check on everything, and by no means will i just start shotgunning parts at it, hoping for a fix. it should have a complete check on everything, with any subpar parts replaced, and everything else cleaned. for now though, i just need it to get me to and from work, until this nightmare job is done.

[i68k]

the screeching is most likely your belt, but we cant hear the sound from here. so the morning was probably screeching because it was cold enough, or the humidity.

if you are going through batteries, its probably because youre alternator needs to be rebuilt/replaced, or the belts tightened. the alternator is an easy fix, once you get the long bolt back in. if youre going to check the tension anyway, pull the belt and see if the alternator locked-up on you. make sure you re-tighten the belts, use the fsm if you need to see a diagram.

also, when the belt is off, you can see the other pulleys better. a full tune-up wouldn't be a bad idea as well.

[jacjm]

haven't driven it in a coupla days. got my g/f's titan back. IT has developed an overheating (when idling) problem,,,, BUT, that's a whole other story. do you think my system rich codes, and starting problems, could be due to a "leaky" injector ?? also, i don't go through batteries. the battery is fine, as long as the car starts (in a reasonable time frame)

[i68k]

a leaky injector could cause all sorts of problems. the ecu will adjust your fuel trim according to other sensors, while it assumes x amount of fuel is being injected. this could amount to both rich codes, from the ecu over adjusting, or starting problems, when the ecu assumes fuel has been injected and fires up. im guessing your belt and deflection were ok? did your alternator lockup or spin freely with the internals?

as for the titan, im not sure about common problems. for general overheating, you can check coolant and oil levels, which you probably already did. as air in the cooling system can imitate an overheating problem, without actually overheating. you also need to make sure that the fans are kicking on, and whether or not they are changing speed. make sure you didnt lose the shroud or something, and overly lean afr would generate abnormal heat levels, also and blockage in air flow of intake or exhaust.

[jacjm]

i will post again, soon- when i get a chance to check some of the (most likely) causes you have outlined,,,(right now i am suspicious of an injector, or more, leaking) i don't have time for anything right now.

[jacjm]

i have devised a sequence for getting it to start consistently. have not checked anything electrically, other than the alternator connections look OK. the screeching is the AC compressor clutch,, pulled in=screeching, out is quiet. still struggling with the other items mentioned.

[jacjm]

OK, i am back to this, again. i drove the car yesterday, for the first time in a while. it started right up. i also started it up coupla times since it has been sitting. after it has sat awhile, it ALWAYS starts right up. it is only when it is warmed up that i have the no start/hard start problem. i am gonna start fresh, and try to figure this out. i WILL research the alternator/voltage output to see what is going on. i need this car to be starting good so i can sell it. i am also gonna start a new post--for the "no start/hard start" when warm scenario. i am about to check the codes again, and see what i get this time. is there an anbient air sensor that may be messing with me ??