So after putting my battery back in and I noticed after the car is warmed up the revs will drop low and shut off every time I start it. The battery light would come on after the car shuts off. I did some research and someone here said it is probably a dirty mass air flow sensor and I have to clean it others said its the battery not connected right so I made sure the connections were as tight as possible but it's still shutting off. The only time it doesn't shut off is if i start it and rev it slightly. I'm going to look up how to clean the maf but if anyone else have any ideas what it might be I would love to hear it. Keep in mind my car hasn't been driven since November and the battery was taken out, and I also have a CAI and plenum space upgrade if that has anything to do with it.

 

Jan, sorry to hear this.
Cars run on batteries,not alternators. I would start simple, get the battery load tested. Make sure both cables are corrosion free.
Good luck.

 

If anything after checking the battery, and cleaning...you'll need to do all the relearns. Since the car has been off for a while and you have a few intake mods. Also how long does it run before shutting off.

 

It will run forever before I turn it off myself or it runs out of gas. The problem is when I try to start it again, it starts then the revs start to drop and it shuts off. It only happens after I shut it off after a while of driving and then turn it back on. It can't be a battery problem because the battery and cables are brand new and have no corrosion. I'll look into the relearns because I think that might be the problem after not running for so long. Also just been driving it for about 135miles for the computer to adjust when I failed emissions this morning because the obd wasn't picking up the machine they had in the shop or whatever.

 

You have to drive at least 50 miles so the obd monitors will set, allowing it to pass. I would do the entire round of "pedal dance" reset procedures and also look for any evidence of rodent activity. They will use your engine, air box, interior etc for a nest.

 

I passed emissions just now after driving around all day. But my Z and the M3 was basically sealed up in the garage. I had 3 different car covers on both of them and put towels in the exhaust and I don't have stock air boxes with either car for any critters to make a nest in. I looked around for any poop or anything scurrying around but I don't see any evidence of rodent activity. I'm going to try the pedal dancing procedures to see if things change. After doing the procedures do I have to drive the car right away?

 

lOL WUT?! You can start a car up then take the battery out and drive away without a battery in it

 

If there's any corrosion, it doesn't matter how tight your cables are. Pull the cables, brush them down, rinse with baking soda (it'll neutralize any acid), then rinse with water, and reconnect.

lol wut? once started, a car runs on the alternator. the battery will prevent spikes through grounding, but it does not "run" the car.

 

I re-read your first post, it sounds as is the alternator isn't getting any excitation or a delayed excitation upon a hot startup. I would hook a volt meter to it and watch the voltage during and after a hot start.

Some cars will "run" without a battery, but not all of them. It's not a good idea to try it either, especially on newer controller area network cars.
The battery's main function is to start the car (DUH), but it also helps for those high electrical spikes that may occur as several systems startup at the same time.
If you switched on the rear defog at the same time as the AC, heat, or lights etc your battery-less car would probably konk out on you.

 

Are we going with this one… again?!

--Spike

 

 

Lol if there were any of these critters they would of made a home in the other car too especially when there is slightly more room for them to hide in. If I was a mouse I would do the same. Also keep in mind that as soon as I start the car I give it a little rev and let them rpms drop to normal and it's fine. Idk if it also might be a fuel issue because with my Toyota a few years ago I used additives expecting to clean the car's fuel system and then a few days later it wouldn't start at all sometimes and I had to press the gas a little to make it start and run normally. I stopped using the additives and it was all better. But I only used iso heet additive a month ago so it wouldn't have problems with the fuel sitting for so long when I start driving again.

 

dont need to do anything just use it its happened twice to me already.. it happened to me back when i installed my 5/16 spacer and pop charger.. i did tons of research and saw that its a matter of just using it till it reprograms itself or something.. i drove it for about a week or two for about 80 miles on the thurway to class until it finally stopped. samething would happen to me on hot starts i would have to rev it a bit. i wouldnt do anything to it just use it and itll stop, some people told me to clean the MAF sensor and others told me not to. i didnt and it eventually went back to normal. its annoying i know.

 

Thank you. With my research I found out that the problem lies with leaving the battery disconnected after awhile and not any of the average intake mods. If it had to do with the CAI I bought the car with or the plenum spacer it would of acted up last year all throughout the summer to winter if that was the case. I searched around the forum and everyone without modded Z's had the same symptoms I'm having and we all have one thing in common, we disconnected the battery for a long period of time by either taking time to change the battery, storage, doing audio mods etc. Driving around or doing the idle reset pedal dance seems to be the solution. Idk why Nissan decided to design the car that acts up from just taking the battery out. Even people who simply switched batterys after the old one was dead had this problem if they left it disconnected for too long. I think I might put this in the FAQ section since this is a common problem.

 

Thanks for correcting me, I'd rather know when I'm wrong.