Starter motor firework display

Honest John Back Room » Technical matters
View Threaded
Wed 2 Oct 2002 18:58
Starter motor firework display - dirtynails
hello
>
I have a renault 5, I replaced the starter motor with a used part which i am assured is in good order. During removal of the old starter i failed to disconnect the battery (stuupid!} and had a lot of fireworks, consequently i replaced the burnt out negative battery lead and the negative lead from the battery to the starter motor housing located at the remote end of the starter motor (away from the the starter armature end). I have connected the positive lead from the battery to the solenoid main threaded connector, however when i connect the battery up i get fireworks at the battery terminal, so obviously stop at this stage, it is a descallier unit and 1986 renault 5 model. note that when dissambling the unit i could not visually see the connection of the direct battery negative lead to the starter casing,i discovered the loose lead only after my first attempt failed to turn the starter which by the way in this initial condition seemed to activate the solenoid plunger as a click was heard, as i kept the old starter unit i figured that the loose lead must have been taken off when i removed the remote end bolt, as the removal operation involved no visual contact with this fixing so i was not aware that anything had been disconnected. two questions.
1) Is the wiring correct i.e negative battery lead direct to the
solenoid casing, positive to the solenoid main pin
2) If so why am i almost fried each time i connect up the battery terminals

The remainder of the electrics lights wipers etc: are ok. without the negative lead to the solenoid hooked up of course Appreciate any tips anybody can offer
>
> joe corcoran
>



Reply | Report as offensive | Link
Thu 3 Oct 2002 14:41
Starter motor firework display - Richard Hall
When you try to reconnect the battery terminal, just how big a spark are you getting? Are you sure you haven't just left the lights on? They'll draw plenty of current.

Failing that - I've never seen a starter motor with a negative lead connected to it (although I stand to be corrected on this). They almost always earth via the engine block, and I'm willing to bet that the loose wire you found floating around is the earth strap between engine and chassis, which had become disconnected somehow. If you have managed to connect this to the feed from solenoid to motor (easy enough to do on some designs) that will give you a dead short and the symptoms you describe. Suggest you start again with basic principles: positive lead from battery to starter solenoid terminal, negative lead from battery to earthing point on car bodyshell, earthing strap from car bodyshell to engine block. And make sure all the connections are clean and tight.

Richard Hall
bangernomics.tripod.com
Reply | Report as offensive | Link
Thu 3 Oct 2002 20:37
Starter motor firework display - dirtynails
Thanks Richard for your willingness to help, problem solved!!
I had negative lead earthed to the engine block so that was ok, simple solution the positive lead to the solenoid ansd then onto the alternator (uh!) yep that foolish i was, my only excuse is that the blooming things are located such tha you cant see what is being disconnected, coupled with a bracket on the rear of the starter unit with a hole and a clean shiny metalic surface local to the hole, suggesting electrical contact, there was also a bolt which i removed and couldnt see a damn thing so with a spare cable and this hole kaboom! daft your right first principles is always the way forward, but getting a diagram of a basic starter circuit was not so easy, im lucky i wasnt fried.

joe
Reply | Report as offensive | Link