Low rpm at start, sometimes battery drains

[ThomasK]

I have a new problem on my 2010 Mazda CX-7 2.3 turbo petrol version. It's just crossed 130,000 km (80,000 miles).

About every 2 weeks / 1000 km, when I start the car, the rpm is about 700 even for morning starts. When the accelerator / throttle is floored, the rpm goes to 1400 max. After leaving it for a few hours, the battery can get totally drained and I have to jump-start it. When I jump-start it, everything is back to normal and the service centre can't find the problem. They mentioned that if there is a low voltage somewhere when starting it, it triggers the Throttle Positioning Sensor (TPS) which limits the rpm. No idea why the battery drains though.

[Tomas]

Have you measured whether your battery is being charged by the alternator while running? Look in the manual for alternator checks and perform those. The alternator has no sensors so there will not be any MILs if its malfunctioning.

Here in the United States of America any car parts store can check battery and alternator for free. Not sure how it works in a Hostel in Estonia or wherever it is you reside.

[MS3Shadow]

Originally Posted by Tomas H Here in the United States of America any car parts store can check battery and alternator for free. Not sure how it works in a Hostel in Estonia or wherever it is you reside.

it's Malaysia, breh.

[KiwiFlavor]

wow.. a Tomas is replying to a Thomas...

[Tomas]

He might be my Malaysian alter ego.

[ThomasK]

Battery and alternator were checked and ok. Low voltage was not the battery voltage. Changed the battery anyway because it caused heavy sulphonation. The connector to the positive battery terminal was also changed as it had corroded a bit.