Peugeot 205 TD - earthing problems

Hi,

I believe I have recently isolated a problem regarding 'hot starting' in my
1991 205. The car is often unable to start after a long run or on very hot
days. I believe electrical resistance in the cars earthing cables have been
increasing with temperature, thus not enough current is able to complete the
circuit to turn the starter motor.

A local garage helped with this diagnosis and replaced a frayed earthing
cable between the gearbox and the chassis. This has helped considerably, but
has not completely eliminated the problem. Sometimes the key needs turning
more than once and sometimes I wait a minute AFTER the glow plug light
extinguishes to allow the battery to offer maximum throughput. However,
yesterday my tricks didn't work and I had to wait an hour for the car to
cool down for it to start (a reminder of the bad old days).

I realise I can jump the starter, but this is both inconvenient and
dangerous (e.g. in a petrol station).

Can anyone suggest a permanent remedy to this? e.g. are there other suitable
earthing points, which cables are culprits and ought to be replaced with
better grade/thicker cabling?

P.S. I am a novice

Thanks,
Clive

 

Hi,

I had a problem with, I believe, similar symptoms on my 205 TD. The 30A
or so drawn by the starter solenoid is carried by the ignition switch,
and there was a net drop of about 3.5-4V between battery and solenoid.
When the engine was hot, the slightly increased winding resistance of the
solenoid was sufficient to prevent it pulling in and engaging the starter
motor.
My solution was to use the ignition switch to drive a relay, which in
turn carries the current for the starter solenoid - there is now
virtually no voltage drop between battery and solenoid and I have had no
problems in the 3 years since I did it.

You can see a schematic of my mod at:
http://www.dur.ac.uk/a.k.kirby/images/starter.jpg

Of course, your problem could be completely different, and could indeed
be an earthing problem.

Aren't we all?
BTW, if you do try this, I would recommend getting at least a slightly
over-specced relay (50A or so) to avoid the risk of the contacts arc-
welding shut :-0

Good luck,
Andy

 

Just a thought, but do you have a loose connection on one of the leads that
carry the starter current? That would cause a high voltage drop and also get
hot.
Obvious culprits are the earth lead, the main leads through the starter
itself and the battery connections. With well over 100 amps going into the
starter it takes only a resistance of say 100 milli-Ohms to drop the voltage
by 10 Volts and dissipate kilowatt!

Robin