Car starting problems

[Chris Holmes]

<Snip>

So. last weekend I swapped the batteries between the two cars…

My car still has the issues, and the other is fine. Which is what I suspected would happen.

One dark morning this week I stalled the car after about half an hour (with dipped headlights on)….

Tried to restart without getting out to put the jump pack on…

Not only did it not start due to turning over very slowly, but I couldn’t get it to stop trying to start (It has a start / stop button, which wasn’t responding).

Fortunately, it started when I got the jump pack connected.

I begin to wonder if It has 2 faults….

One, the alternator isn’t putting out enough current to run “the car” (involuting headlights) while also putting a decent amount of charge back into the battery (but the voltmeter plugged into the cigar lighter shows

14ish V when running)

Two, it takes more current than it should to crank the engine.

[Animal]

What battery voltage do you get during cranking? 9-10v is ok. High means a high resistance point in the start circuit, low means the battery isn't coping.

14v is a little low in warm weather, I'd expect more midwinter. That might be your primary problem. Charge endpoint at 0degC: 15.3v. At 10degC: 15.06v Sounds like either your meter or alternator isn't right.

[Rod Speed]

So that isnt likely to be the problem and you should check the voltage when cranking the engine over.

Or its got a poor connection to the starter motor or a faulty starter solenoid and that's why it turns the engiine over too slowly to start.

[Chris Holmes]

<Snip>

Thanks for that, I’ll check the voltage when cranking…..

Hmm…. the cigar lighter gets turned off then I think, so I’ll have to find another way to monitor it.

Are you saying that 5.3V would be normal / ok when a car is running / charging?

When my last car was up around that voltage (with a “supercacacitor” in // with the battery), someone on another forum told me anything over 14.5 could fry things.

In other news, yesterday in a nice warm multi-storey car park, (with the jump pack) it span over really quick and started immediately.

[alan_m]

or you have a high resistance connection starter motor to +ve, starter motor to engine fixing, -ve battery to engine or chassis. It only has to be much less than 1 Ohm when a starter motor can take 150 Amps to cause theses types of problem. Electrolytic corrosion between different metals for starter motor and engine?

[Animal]

cars routinely go above 14.5v. Lead acids need more volts to charge fully in winter.

[Thomas Prufer]

... and one way to find that is to monitor the voltage and its drop along the path from battery to starter...

Thomas Prufer

[Chris Holmes]

Thanks both.

One of the problems is that without a nice warm garage and a 4 way lift, its very difficult to get to the starter.

[Thomas Prufer]

Drive up on a kerb, on the side where the starter is. Crawl under, using the extra space for comfort.

BTDTGTTS. It's about as great and exciting and *fun* as it sounds.

Thomas Prufer

[Animal]

you don't need to, as already explained

[SteveW]

Yes. I changed my clutch cable that way, after it snapped on the way to a friend's house. Unfortunately it was raining hard by the time I got hold of one, so I was effectively lying in a shallow stream while I changed it :(

[The Natural Philosopher]

I trump that with replacing a split lower radiator hose lying on my back in 4" of SNOW.

[Tim Lamb]

I have a pair of ramps and plenty of concrete floored barns.

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[charles]

I had a colleague who dismanted his A35 gearbox in a similar situation. He brought a shaft into work and rebuilt the cogs with araldite and then re-assembled it

[Animal]

hard to believe that lasted 5 minutes. Araldite, if set cold, turns to gloop when it gets hottish

[charles]

At our last house, I built a garage - with an inspection pit.

[Chris Holmes]

I was thinking of the taking the starter off to check / clean the connections (though I suppose depending on what the meter tells me, there may be no point).

[Chris Holmes]

Nobody likes a showoff! :)

[Chris Holmes]

Are you offering? :)

[Tim Lamb]

:-) Removing the undertray will be tricky using the pavement method.

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