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Flat battery when hot, good when cold?
AndyW - 24/8/13 at 09:23 AM

Quick Saturday question.

Car starts perfect when cold, when been running for ages and is nice and hot it, wont start, battery totally flat, car then cools down, i.e been off for a while and starts perfect again.

Could it be a case of simply not properly charged or a dodgy earth somewhere?

Ta

Andy


unijacko67 - 24/8/13 at 09:29 AM

More likely to be starter or tight engine when hot. Try full beam when cold and hot to see if it is battery. My pinto used to do it 25 years ago. What engine ?


RichardK - 24/8/13 at 09:31 AM

Is it charging ok? Just wondering if its over charging and boiling the battery??

First thing to check mate.

Cheers

Rich


AndyW - 24/8/13 at 09:35 AM

quote:
Originally posted by unijacko67
More likely to be starter or tight engine when hot. Try full beam when cold and hot to see if it is battery. My pinto used to do it 25 years ago. What engine ?


2.0 zetec


snowy2 - 24/8/13 at 10:40 AM

sometimes caused by knackered ignition timing module giving full advance when hot reguardless of engine revs


britishtrident - 24/8/13 at 10:54 AM

Ignition has too much advance at cranking rpm and is trying to start backwards against the starter.

A common problem especially on Fords what ignition system are you running ?


Smoking Frog - 24/8/13 at 11:07 AM

Had this once on a XR3 CVH engine I think it was the starter internally expanding due to the heat. It just seemed as though the battery was flat when the engine was hot. Very inconvenient at the petrol station where you have to switch it off to open the fuel filler then wait 20 mins until it cooled down. After weeks of head scratching tried another old starter and it solved the problem. Not sure which side the starter is on the zetec, if it's near the exhaust manifold, but it's something else to check.


David Jenkins - 24/8/13 at 02:48 PM

Had a similar effect recently: started OK when cold, barely turned over when hot.

Worried about it, kept think of all the horrible things it could be, but it turned out to be just a loose connection on the starter solenoid (high current side). Don't know why it behaved differently hot or cold, but now it's tightened up the engine turns over smartly no matter what the engine temp.

I'd go through all of the high-current connections to the starter, and the lead from the battery to the chassis, making sure everything is clean and tight. It's a zero cost check, won't take long, and it'll be one possibility ticked off if that isn't the problem.