So i'm finally somewhat satisfied with my g's ride after a hectic month of repairs and problems (Cracked windshield, Muffler leak, spark plugs, ignition coils, valve covers, basically all gaskets, knock sensor harness), mind I have had the car for about 5 years and this is the first real money I put in it to repair besides oil changes and tires/brakes. So i'm pretty happy except for one problem that remains lingering. My car starts completely fine when the engine is cold, for some reason when the engine is warm and tries to turn on it's like a 90 year old getting out of bed. Has never failed to start yet but something isn't right. I figured it was my broke ignition coils causing the slow start but after replacing nothing has changed. my next idea would be to get my battery tested maybe it has barely enough juice to start the G. probably going to bring it to autozone and have them test it for free sometime this week.

Any advice or opinions would be great!

(98k 04 g35 coupe stock)

 

Best place to start is with the battery, heat is the worst enemy of weak batteries! Have it tested, any indication it's bad step up to one of those red top Optama batteries...they last forever!
Gary

 

If your car sat for 5 years with that battery in it, i'm surprised it starts at all using that battery now.

Make sure if they test it for you that they do a load test and not a capacitive-resistance test. Load testing is the best way to know almost for sure if your car battery will really work as it's intended to or not.

It's also possible that the starter motor is worn too and in need of replacement as heat can often cause electric motors to run very weak. This is a common problem in motorcycles, but not usually too common in cars where you have a beefier starter and generally more space around the auxiliary engine components for heat to dissipate.

Try the battery test first though since it's your most likely cause and easiest to test.

 

+1 for those optima deep cycle batteries, or anything that's a helical plate deep cycle. AMAZING starting power.

 

The car didn't sit for 5 years, I've been driving it, I purchased it 5 years ago from the original owner who used it as a weekend car garage kept. (bought at 52k now 98k ) I did most the damage on it, I just got the battery tested and it came back fine fully charged. Looks like my last option is the starter.

 

If it has issues only when it's hot, I would say it's not the starter. The starter only engages once when you first turn it on.

I'd look at something that is affected more by heat like a cam/crank sensor, engine coolant sensor, or your fuel pump. I'd look at the starter last. Does it crank when it's hot everytime?

 

Thanks for the info any of these places you think it is more than the other?
Car hasn't failed to start
starts sluggish
if it was the crank or cam shaft sensor wouldn't it cause a code?

Thanks again,

 

Before you become a "FriedFiish" take your G to Nissan, have them check it out! No reason to throw $$ at a new starter if that's not what's causing your weak start issues!
Spend a little to save even more...Gary

 

None of those things has anything to do with the car turning over slowly while cranking. The only things that matter for that are voltage/current to the starter, compression in the motor, strength of the starter motor, and good clean contact of the starter gear with the flywheel.

 

The OP said his car starts fine when it's cold and starts sluggishly after it's been warm. He doesn't mention an unusual long crank time or if the car just takes awhile to idle normally after running. If his car had issues starting cold or warm then I would check the battery, alternator, cables, and voltage drop first. I'd probably check those things anyway, because hey you never know.

But, if the issue only occurs when the car has been warm. I'd be more inclined to take a harder look at things affected by heat, which can include the battery, starter, sensors, motors, and the wiring. What he shouldn't do is just throw a starter, battery, or whatever on it to see if it's fixed.

If his battery and charging system was load tested and passed, I would say look at something else. Nothing wrong with checking a fuel pump or sensors if you're having a hot start issue. Sensors, motors, and other things get affected by heat just like you stated yourself.

 

I think we need further clarification from the OP as to the details of his weak start issue. I interpreted his description of the problem from the original post and the title of this thread as it was not cranking powerfully when warm.