Car starting problems

[Chris Holmes]

Hi All,

I posted the following in uk.rec.cars.maintenance but fidn’t get much response….

There are some updates at the end…

“I bought a 2006 2.2 D Toyota Corolla Verso in Nov 22…

It didn’t like starting in the cold / damp. It could be started with the aid of a jump start pack, unless it was below 0 degrees Celsius, in which case the engine barely turned over.

A jump start from a similar spec car would then start it.

Replaced the battery, no difference.

Fitted a supplementary earth cable from the battery to the engine (near the starter) and it now starts without the jump start pack, but not this morning (-7 degrees).

I (and a tyre place) have tested the battery (when warm) and it is fine).

So next step…..

Replace starter??

Or could I put the battery on charge for a few hours in the morning prior to trying to start (and thus nurse it through the small number of really cold days between now & spring??

Or test the battery on a cold morning (perhaps it really doesn’t like the cold??”

I had the battery on a smart charger last night (still attached to the car) and this morning (7 degrees C) and it read “Ful”…

I put the jump start pack on and the car started (a little reluctantly).

I then drove for half an hour or so (dipped beam on, A/C on, but no heated rear window or other power hungry stuff.

Then switched off (lights off) for 5 minutes or so, and tried to start the car without the jump start pack…

It span over reasonably fast, but didn’t start. After about 5 seconds it started yo slow down.

I put the jump start pack on, and thankfully it started (after turning relatively slowly.

I am going to swap the battery with the one in my wife’s (near identical) car and see if the fault stays with the car, or goes with the battery.

However, I would’ve thought that if the alternator was working as it should, it would’ve put enough back in the battery for starting a warm engine without any issues.

Thoughts??

[Smolley]

Have you checked the pre-heater coil and also diesel goes thick in cold weather and doesn't flow from the tank easily.

[The Natural Philosopher]

Diesel is sold with enough additives to make that not a problem and the fuel pumps should be able to deal with the extra viscosity.

Batteries can be load checked at any halfords or battery supplier

On a 'crank no (cold) start' on a diesel, it's generally glo plugs. If it otherwise runs OK.

If its barely starting and running like crap, suspect low pressure fuel pump.

If its not cranking at all hardly, something else is up. Something electrical

[Colin Bignell]

On 19/01/2024 13:18, Smolley wrote: ..

In the winter of 1963, at Old Oak Common railway yard, they had fires in old oil drums between the tracks to try to keep the diesel in the locomotives warm enough to flow. It worked until one night somebody let them go out and the next morning steam shunting engines were the only locomotives that would work.

[Smolley]

It was very cold over that period, but not so bad as 1947.

[Smolley]

[Fredxx]

Does it have a pre-heater coil?

Before replacing glow plugs, as per your latest post, I would use a DC clamp-meter to measure current to the glow plugs rather than simple replacing them?

[Colin Bignell]

Not so many diesel locomotives in use then though.

[The Natural Philosopher]

will get you there.

But if its not starting once *warm*, it's probably not glow plugs

[Fredxx]

Sounds like a job for a code reader to check fuel pressure on cranking, assuming this has a HP fuel pump.

[Brian Gaff]

To me though it sounds like the engine is stiff and the method of powering the starter, or the starter itself, have not got enough guts to actually turn over the engine. Diesels tend to be this way in cold wether, and many big trucks actually warm the fuel at start up, I can remember back in the big freeze of 63, that the fuel was in fact freezing in the tanks. The worrying thing in your story for me is the problem of voltage drop on what should be a direct and short DC path through a decent relay or solenoid, yet its often starts with jump leads, My late father used to say it was a very bad switch that was the cause Brian

[Chris Holmes]

It just started fine at 6 degrees C after sitting about 7 hours. (with the jump start pack (may have done so without, but I couldnt risk it).

I am beginning think that the battery performs well under spec at -7.

[Tim+]

Has someone dumped a load of 20/50 oil in the engine instead of the modern runny stuff?

Tim

[The Natural Philosopher]

That doesnt fit the symptoms.

It isn't starting well *even when warm*..

[Paul]

Voltage drop is normal though.

I've recorded the transient behavior of my car starter.

T=0 Battery voltage 12.5V

Trough voltage at battery terminals 9.5V at ~150 amps (mid-crank, just before ignition)

Both the voltage and current, were recorded by meters that have peak/trough record capability. The 150 amps then, is the "peak" current. A good starter on a petrol engine (depending on displacement and number of cylinders), can be between 100 amps and 150 amps for a four cylinder.

I have no idea what a diesel is, but they're going to pick an electric motor for the starter, suited to a range of conditions, including starting at -30C.

You can do the maths, 3V drop divided by 150 amps, to get a rough idea of the internal impedance of the battery that day.

I would suspect the voltage regulator is not charging the battery properly. That is a common practice on modern cars. That, and vampire loads overnight, draining the battery down. Sticking a clamp-on DC ammeter on the main battery cable, will tell you what the leakage current is.

If a car is having trouble starting, and the battery and voltage regulator are working properly, you should get maybe a half dozen cranks before the battery is used up. If you do one crank, and a second crank is "squeamish", then the battery was never full in the first place. The fullness of a battery, requires a temperature correction, for accuracy. Whether you use terminal voltage (after battery has settled), or use a hydrometer, both have a temperature correction table to determine "fullness".

When a lead acid battery is fully charged, it's roughly like laboratory 12 molar H2SO4. When a battery is drained, the freezing point of the battery is only -2C and the consistency of the liquid, is like water. The syrup consistency and 12 molar equivalent, tells you the battery is doing reasonably well. A fully charged battery will not freeze until -55C. If you find your battery frozen, it means it is in a poor state of charge.

On the old cars, you'd just "bend a piece of metal" on the voltage regulator, to change the regulation point. On some modern cars, the mechanic will claim they have no ability to change the crappy behavior of the car computer. Exactly why "sub-charging" a battery is good for it, that escapes me. A battery works a lot better, if you keep it charged and keep it out of the soup.

If this was my car, I would be running the mains-powered charger on the battery. During charging, the terminal voltage rises to

14.4V or so. If the voltage rises higher than that (16-18V), then the battery is bad. A smart charger, can also give an indication via LED display, that the battery is bad. The charger needs to be temperature-compensated, to predict the fullness of the battery when filling it. It will make filling errors (like mine), if it does not have temperature compensation build in. Some professional chargers, actually have a temperature probe you fit to a battery terminal, to get some idea of current battery temperature.

If the car starts properly at -7C, and it has just received a mains charge cycle, and yet the car won't start at -7C if the car charged its own battery, then you have to ask the shop "WTF" regarding voltage regulator setting.

Paul

[Fredxx]

There is a good reason, reducing alternator load reduces fuel consumption and hence emissions per mile.

Most cars now charge it's battery to 90% and then only increase the level of charge when coasting.

Sorry, I disagree. A good battery will allow the volts to rise when at at full charge capacity. A poor one will gas and hold the volts at a lower level.

As above. It also depends on how long a journey you have to put the energy used in starting back into the battery.

[Thomas Prufer]

Measure the current.

As you might not have a (clamp) ammeter that does DC and the range required, the voltage drop along, say, the ground strap is a good proxy. "Calibrate" by turning on the headlights, calculating the nominal current draw (2 * 55 watts is

110 W and about 9 amps at 12 Volts) and putting that into relation to the voltage drop on the ground strap (a few to a few hundred millivolts).

Before going for the glow plugs (expensive), check the glow plug fuse (reseat or replace, usually a strip of metal, cheap) and the glow plug relay.

Just my 5 eurocents.

Thomas Prufer

[The Natural Philosopher]

Before f****ng with the glo plugs, bear in mind they play no part on a warm start whatsoever.

[Fredxx]

They might not on a very old vehicle, but modern diesels with a moderate turbo boost will often run the glow plugs for some time after starting. Including a warm start.

High turbo boosts along with emission regulation results in lower compression ratios.

If the air temperature is very low, even with a modest compression, you might still need a glow plug for successful detonation.

Making sure the glow plugs are working is a smart option before attending anything else. I also think a clamp meter capable of measuring DC current (be careful in your purchase as some only do AC current) is a very useful tool.

[Animal]

It's worth being aware that some diesels need every bit of their cranking speed to get going. In such cases even a hardly noticeable drop can fail to start. I'd start by checking 3 things:

1. battery charge, using a temp/charge/voltage table.
2. Alternator output voltage
3. Check you terminals & clamps are cleaned, greased & properly seated