*Long* sad story - V Corsa reversed charger connections,

Check the battery connectors to ensure they are secure?

Well the normal checks apply, are the earth leads & battery clamps clean & secure? Does the battery light go out then? What's the battery voltage with & without the engine running?

Good advice, I had similar problems years ago with a Ford Escort, I took both cables off, wire brushed the lead terminals on the battery and used a tiny wire brush to clean the round insides of the + and - terminal connectors so that it was clean metal to clean metal....after tightening I applied a coating of vaseline to keep damp off.

Lights dimmng with the engine running? You got an extraordinary high resistance somewhere in the ignition circuitry? Can't think where though, maybe a wire came loose and fell onto a bridge for the same circuit with high resistance??

Unlikely, but possible.

Make sure mobile has full charge and credit, pack a good sleeping bag and a survival blanket?

-- Billy H

Petrol engine?

If tit is a high resistance, maybe it in HT circuit, if the thing didn't fire but battery okay (turning starter) then I'd bet it wasn't the battery connections 'cos you're drawing maximum amperage when you turn over the motor.

mm, it'll be one of these new no-fum motors with a feckin brain-dead box in it right?? No longer dizzy but brain dead? If it was dizzy controlled, maybe you got muck in the dizzy head? that'd up resistance but wouldn't necessarily equate to low lighting.

"Engine" warning light flashing

In message , Derek ^ writes

There was someone selling a 5 series BMW for £300 in UKRM the other day

- comfy ride for 700 miles

- just go ands buy another cheap car for the trip and flog it on once you're sorted again

It's usually poor terminal connection at the battery, or more likely in this case, a dodgy earth strap somewhere.

Christian.

He said his starter is turning the engine, battery terminal connection cannot (to my mind) be to blame.

Maybe an earth in the ignition circuit.

A bad connection can cause a significant voltage drop when the starter is turning, causing the ignition system to malfunction. As Christian says, check it.

The problems are intermittent. However, I agree, it is more likely that the poor connection is elsewhere. The earth straps between engine and body or to the engine management system are frequently suspect in these situations.

Christian.

I should have mentioned before it's petrol with electronic fuel injection

It was arseing about again this morning when I went to start it.

Turning the ignition on but not as far as "start", has the "engine" warning light flashing, and the mechanical warning light (pictogram of a car outline with a spanner across it.) lit continuously. Turning the key to start results in the starter turning over enthusiastically but only sporadic firing. Buggering about like this for two/three minutes results in the engine starting, whereupon all warning lights go out and the car drives normally (in daylight with headlights off & minimal electrics) .

These aren't the normal symptoms of a low battery in this car and the starter motor does turn the engine over very well. I suppose I might have disturbed the 12 volts feed to the electronics when I put the big Croc clips on the battery terminals.

Since it is SWMBO's car I've taken it into a garage (she'd permanently lose faith in it if it ever let her down) and taken out a cheap rental car for the business trip. I can't afford to let the customers down a second time in 10 days.

I think I might have damaged something electronic by connecting the battery charger the wrong way round. I'm hoping it's nothing too expensive, the ignition was off when that happened and the car battery itself should have presnted a very effective short to the puny little plastic charger.

Or so I hope. 8-(

DG

I had huge issues with a certain car when its battery was dying.

Yes, I could start it, but the voltage stayed permanently low..and the electrical stuff was all over the place..ABS and transmission warning lights stayed on for 50 miles before going out, electric windows lost their 'home' positions..

Traded it for another car that ALSO came with a dead battery. That one would start..but not hold charge long..and the engine was very rough until the volts came up. A new battery under warranty fixed everything.

It seems that most of the modern electronics needs about 11v or more to function properly, wehreas a starte will happily crank on 10 or less.

I would change the battery before dong anything else.

Thanks folks for pointers so far.

The car has been in a garage for 4 days this week, and they say they can't find out what's causing it. They have a diagnostic computer and they say the car does not report any fault codes whilst the fault is present and the warning lights flashing. The have checked the emu by simulating a fault by disconnecting the temperature sensor and it did report the correct fault code. So the fault detection and warning section is not dead alltogether.

The alternator is charging at 19 amps @ 13.8 volts.

Whilst the starter motor is cranking the engine the battery voltage reads 13 volts.

All connections/earth straps have been checked.

Currently the engine starts a bit like a cold carburettor engine when no choke has been used. Sporadically firing for a few revs before stopping. After about 2 minutes of this (when there is sufficient unburnt fuel in the cylinders, and the cylinders a bit warm?) it will eventually start and run quite normally. Once up to full operating temp it will restart without difficulty and no warning lamps illuminated.

DG

A couple of thoughts.

1/. if you can blag a scope, have a look at the charge waveform. If you took out one or more of the rectifier diode, you might be getting excessive ripple at lower voltages. Enough to upset the electronics..or possibly a voltage regulator in the ECU has gone. Replacing a rectifier pack is normally not too expensive - or a recon alternator. A dodgy ECU IS expensive - generally the best option is a scrappy one.

2/. Poor cold starting just means its not going rich on startup..its certainly worthwhile removing the main temp. sensor and putting a meter across it while you plunge it into a saucepan of boiling water. I spent weeks tracking down the reverse fault,..sensor was permanently high resistance and the car was on 'full choke' and had to be run at 3000RPM plus when hot, or it would stall flood and never restart. A new sensor was £11.50.The fault codes will detect an open circuit and a short, bit not a resistance within 'working range' that is nevertheless not working with respect to temperature.

And took 10 minutes to replace.

When I bought a charger, the instructions said "If you connect the leads the wrong way round, an led will light".

Cool, thinks I, and tests it. LED lights for a microsecond. Back to the instructions:

"and the fuse will blow"

Whoops. I still needed to charge. So I stuck a piece of silver foil in the fuse holder, connected it the right way round, and never left the charger unattended....

Ben

LOL!

Sometims plugtop ones will fit.

Chris

Resolved now, the long & short of it is the problem gradually improved and symptoms went away one by one.

Chancing the last 700 mile return journey Leeds>Aberdeen>Leeds in darkness clinched it.

A work colleague suggested that I may have scrambled the memory in the ecu and it had to "re-learn" it's settings. Only guesswork.

It's equally possible there was a bad battery connection which the garage resolved whilst it was in for service, the rest being down to getting some charge into it.

Thanks everybody who helped.

DG