Uneven Idle Issue?

[Envitro99]

Hi everyone,

it's been a while since I posted here but I've brought my MR2 out of storage for the winter and will be doing some well-deserved engine and body work on it this year and through the winter, since I finally have a garage.

Couple of things I noticed:

1) the engine idle is really uneven, nothing extreme but it bounces up and down between 800-1200rpm, even when the engine is warm. I don't recall this being an issue before, but it coudl be related to my battery problem below.

2) the battery was completely dead, it has issues holding a charge; this is the second battery that I've had to replace in 2.5 years for the same reason. Once a new battery is in it works fine and everything is good, but as soon as I park it over a winter it just craps out completely and won't recharge. The car runs fine once boosted since enough juice is supplied by the alternator.

Any help would be great if you guys can offer it. Thanks!

[GQBalla]

do you leave the battery in while you store it for winter?

[thinmyster]

your battery probably froze and is now fukked. Take it out every winter and charge it occasionally. I go through batteries yearly because im lazy.

Buy your batteries from walmart from now on and they will warranty them as many times as you can bring them back within two years. Canadian tire limits you to one battery return per purchase/warranty.

Idle could be due to air in the coolent lines or a temp sensor.

[Nissan_Fanboy]

Check your thermostat in the car,
and get a new battery haha

[Envitro99]

Well, I have the battery and will get it exchanged since it's only a year or so old (3 yr replacement warranty).

I'll check into the thermostat.


Thanks!

[mr2mike]

Not really the thermostat but make sure there's no air in the cooling system. It can cause idle surge like Nissan_Fanboy said.

I guess it could be an issue with your charging system if the system is being strained that much to charge the battery but it usually doesn't idle surge. But the alternator could be on it's way out if the engine isn't getting enough juice. Usually a high rpm drive, the battery light or other dash lights will flicker.

Also check for a boost or vac leak. Most common issue with bad idle.

[ryder_23]

TPS, liek said air in coolant, vac lines, fitv (if your car has one, or maybe something similar)

[Envitro99]

looks like as soon as I replaced my battery the issue went away

[mr2mike]

Wow.

I'm amazed your car even started with that battery then.