starting problem...please help

[pradip.patel]

G35 coupe with 53k on it, the car runs great and has no other issues except it wont start well when HOT, it will start and than goes back to idle...usually requires couple of keys before it starts back up....my guess is idle sensor but i could be wrong....

[kmckis1029]

does your temp gauge say the car is hot when it finally starts?

i would check my anti-freeze fliud level first... then oil level... as i remember one time my sisters car acted like yours; it turn out it was a fail-safe because her engine ran hot and burned the oil up... once she got the oil and anit-freeze changed the car started fine again hot or cold.

if those two fliuds are ok... then it might be some sensor messing up... but if you car idles normally once if starts then i wouldnt think the "idle sensor" is messed up...

just my suggestion... i know there are people on here that know more about this car than me...

[joe603]

Welcome to NICO!

First, what year is your car? Need more info on what the car is doing when you start it cold or hot.

[pradip.patel]

thanks guys, ok the year of my car is 03, and no there is no change in temp...temp is fine...its normal......let me see if this helps narrow things down...lets say i was driving the car for more than 15 minutes and than i let it sit for about half an hour or so there is no problem with starting at all....the problem only arises when i try to start the car while engine hasnt had time to cool.....when the car is cold in the morning it start just fine...and the fluids are okay as well.....my guess is some kind of sensor...but i dont want to pay the dealer for things that dont need to get done as there is nothing else wrong with the vehicle.....thank you guys for your suggestions....i hope this helps....

[joe603]

Is there a CEL light? (SES)

What does it do when you try to start the car when it's hot? (What sounds do you hear ect...)

[Jacko3]

pradip.patel:

Take your car to autozone and tell them to give you a brand new spanking battery. Your battery is shot, and it is running down your alternator. That your car even starts at all is testament to the superior quality of Infiniti Alternators.

Your alternator is working over time. When your car is hot and warmed up, the brushes maybe slightly exapanded away from the rotating magnetic spindle while it charges the battery. When it is well cooled or when the brushes are closer to the magnetic spindle, it then has enough flux to charge the battery which invariably cranks the car. When you turn the car off briefly, and because the battery is already dead and without adequate fluid for charging, the heated alternator is unable to send enough voltage to crank the car because of the heat effect.

It has to cool for a while for the brushes to come closer to the rotating magnetic spindle in order to produce enough charge for the battery. I may be blowing smoke up my friggin a$$ with this explanantion. But it wouldn't hurt to change the battery, would it? And if the problem is the battery, i would advise you to change your alternator as well, or else, the problem will repeat itself within months again.

One or two cells in your battery may have very little or no fluid fluid in it to conduct enough electricity. Thus, your alternator may have been working overtime to get your car cranked for a while now. I have learnt over time that the best way to save an alternator and get a lifetime use out of it is to replace the battery far more frequently than is required. For example, if you battery has a 4 year warranty on it, please change the battery at 2.5 - 3 years. By so doing, you just extended the life of the alternator by another 1 year. Alternators work the hardest when the battery is getting closer to its death.

I personally will be changing my battery at 40K - 42K regardless of how nice my battery looks. And at 53K, you still have warranty on that car. So, go to the dealer and let them get things checked under warranty. Just my 2 cents. I could be wrong. Again, all my ramble is mere speculation. What does Jacko know? Nothing!!

I love this bunny.


Modified by Jacko3 at 11:12 AM 12/2/2008

[Sentientbydesign]

Sorry Jacko,

Gotta chime in and straighten up the facts. The alternator has nothing to do with your startup. The reason batteries have CCA (cold cranking amp) ratings is because when you start your car, the starter motor uses a significant amount of current from the battery to turn the engine over and get it running.

I do think this issue is electrically related, but I HIGHLY doubt it has anything to do with the alternator. The battery is an unlikely suspect as well. Especially since it sits in it's own compartment away from engine heat.

The issue might be as simple as a corroded or worn sensor harness. Starting problem where heat plays a role usually mean there is a thermal expansion issue.

We need a clear description of what still works when the car won't turn on.

... it will start and than goes back to idle...

I have a problem with this statement. The car is supposed to idle. This is when the engine is running, but is in neutral or park. Idle rpm is usually 650 rpm.

pradip.patel, did you mean to say that the car will start, then stall?

Do your lights dim significantly when you try to turn the car on?

If so, the battery might need replacing, though it probably won't fix your starting issue.

When the car is running fine, do the lights dim while under heavy acceleration?

This would indicate an alternator issue. Really unlikely, but I'll throw it out there.

Do you make it a point to wash your engine?

Doing so may have corroded a sensor harness. It's possible that the corrosion and thermal expansion are at fault.

Another possibility is a Mass Airflow Sensor or Vacuum issue. I would lean more towards the MAF than the Vacuum because a clogged vacuum line should breath better while hot than cold.

[kmckis1029]

great suggestion!

[pradip.patel]

Thank you all once again for giving me some great advise....ok so my 1st reaction was battery as well and becuase its beein few years i changed the battery hoping the problem would be solved...but it didnt ....and another thing is that it starts and than stalls and turns off however if i give it a bit of gas than it prevents it from stalling and stays on....and as far as washing the engine i have done it once while back....so that may have messed with some kind of sensors....ohh and becuase the model is from 03 i believe the warranty is done.....and as far as lights dimming and such I really havent paid much attention to it but I will check it out.....so basically its not the battery for sure cuz i changed it....hopefully now we can narrow it down....once again i want to thank you all....my friend who also owns a G turned me on to this forum and i must say that it has been very helpful so far and everyone is very friendly....thank you....

[Sentientbydesign]

I would expect, based on your description, that you either have a MAF (Mass air flow) sensor problem or possibly some other intake obstruction.

Have you checked your intake filter recently? Also check all of the vacuum lines (rubber hoses) that go into the intake tubing and the intake plenum.

Does your check engine light come on?

[pradip.patel]

OK i will check it out....thanks....and no the engine light has never came on....but i will deff check all the hoses and try and pin point the problem....

[Jacko3]

We are glad to be of help. I had no idea you had replaced the battery at least once. You earlier description was not very accurate. Now, judging by your most recent description of the problem, I have to agree with Nate that the issue is probably a "MAF (Mass air flow) sensor problem or possibly some other intake obstruction." I am with Nate on this one.

But you are going to have to start by replacing the air filter to checking the MAF to ensure it is clean, to conducting an intake induction system to clean your plenums, to cleaning the throttle body, to resetting the throttle and intake volumes. Most of the sensors in our car should trip the CEL. So, its sort of odd that the CEL has not come on yet. Either way, you may have to pay the dealership some money to get things going. Also check your PCV valve and replace it. This is a togh one. But i would agree that starting with the small stuff would be a good idea such as checking the vacuums and hoses.