Car starting problem

G a f f e r

Well-known Member
Toyota RAV4 2014 2.0 petrol CVT.

Weird thing happened to the RAV4 couple of mornings ago. Acted as though battery was out - wing mirrors worked once then car refused to start, instrument cluster flickering when attempted.

My wife left it at home as it appeared to be dead (took a taxi to work after a few attempts to start it) and when I got back from work, I attached my jump starter pack to it which indicated the battery had only 4.5V !!!!
Anyway, started the car but jump pack indicates it’s still at 100% charge (normally the pack would be down at about 70% after a jump). This means the pack wasn't "used" at all - the car had started via its own battery alone.

After about 10s, the engine then faltered and died (this has never happened before).

So I restarted and it started fine (again, jump pack showed 100% remaining so that hadn’t been used) but it had a rough idle. Drove to pick my daughter up from nursery (10min drive) and it appeared to be ok - normal acceleration and ride.

By the time we returned home, car appeared to start with no issues after turning off.

Checked alternator and it's a steady 14.05V. Checked battery with engine off and it's a steady 12.55V. Attached Optimax Charger and it indicates battery is slightly low but not excessively low.

So I don't think it was/is the battery/alternator.

That rough idle? Still there at this point with rpm varying from 500-900rpm whereas normally it sits dead on about 750rpm

So I then drove around the block a bit and it’s now back to normal. Idling normally, driving normally, starting normally. No engine light showing either btw.

It’s got me a bit stumped really. Could it be bad fuel? Or maybe some temporary crud in the injectors/filter?

It’s been running fine the past day.

It’s due a service so I’ll get them to check out the fuel system whilst they’re there (need to wait for them to fit me in) and I also added some redex to the tank - might be pissing in the wind but I had some in the garage and thought it wouldn’t hurt to attempt to clean the fuel system a bit.

Just wanted an idea of the bill I’d be expecting.


Distinguished Member
Loose battery connection? With low current, gives you high resistance and low voltage, but heavy current demands kick the connection back into life. Check all battery and high current leads are secure.

Rough idling probably due to excessive AC being dumped onto the power line as the battery is not performing the normal level of smoothing.


Well-known Member
chuck some redex in it and give it a thraping down the motorway.

Always used to work in the old days.

All jokes aside it might benefit from a good ride about getting into high revs for a while and having a general workout.
I think the clue might be in the 4.5v measurement. If your pack was connected to the battery terminals then I would suspect a bad connection of one or both battery clamps. If your pack was connected to a body earth then it could be the battery positive connection or a bad earth. So I would remove and clean battery clamps and if applicable check the high current earth path as well.

G a f f e r

Well-known Member
Thanks for that guys :thumbsup:.

Did it today using this guide. The +ve was OK but the -ve terminal had a some of crud on it. Cleaned both and reattached.
I'm hoping that's fixed it and it won't happen again (it's running fine) but i'll update this thread if anything else occurs.

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