Peugeot 205 TD - earthing problems

[Clive (archive)]

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

 

[Albert T Cone]

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.

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

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?

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

P.S. I am a novice

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

Thanks,
Clive

Good luck,
Andy

 

[Robin Bendall]

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

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