Suspect Starter Connections behind Radio

[hvanman]

Hi, A while ago I swapped the ignition switch unit for another as occasionally the starter would either not operate, or there was a delay after turning the key. All was well for about 6 months and then the same problem came back. This time I just cleaned the connector contacts where they join behind the radio and everything seemed OK again until my recent trip to the South of France where the problem returned with a vengeance, linked to driving time/temp (always perfect first thing in the morning), resulting in several bump starts being needed and almost blocking an entire level of a Eurotunnel train on arrival in the UK.... (opening the bonnet to let it cool also set of the fire alert in the carriage as it appears it is very sensitive to temp I was told..) Wiggling the cables sometimes resulted in operation, but once really hot, no life at all, making me wonder if actually it is starter motor related? However, on a couple of occasions I also lost the dash lights/electric windows etc, so I do still suspect the switch/connector)

To test the cheapest option first, I want to bypass the relevant wire in the connector to remove that failure option.

Due to the awful access, does anyone know which wire in the two connectors is the one that takes the power to the solenoid on operating the switch, to save a lot of back ache in the footwell...

Many thanks. Simon

[RobC]

I'm afraid I don't know the answer to the wires question but I can speak from experience when I say sticky starters are very likely to be the weakening of the switch/wiring to the ignition switch.

(Coincidentally I have just got back from a trip to the south of France in my BX and the starter failed me once, in very heavy traffic in 32* heat! Luckily was on a hill so bump started it before the impatient french drivers got too irate)

I would suggest just plunging in and doing the starter solenoid relay modification. I installed my relay with the others by the rear washer bottle. This way you can get the full 12v to the solenoid without it having to go all the way into the dash via the degraded wiring and back again.

[mat_fenwick]

Interesting. I had this problem a year or two back, and I did the relay mod but fitted it to the injector pump partly for simplicity but partly to keep the wiring as short as possible. My longer term plan was to establish exactly where in the loom the voltage is dropping.

Recently (again very temperature dependant) I have been seeing the same problem, coupled with a (more severe) dimming of the dash lights when I brake. I was able to measure voltage between battery positive and starter solenoid trigger at 6 V, so obviously a significant drop somewhere. This was presumably not enough even to switch in the relay coil, especially when hot and the magnetic field generated is weaker. I then measured across the ignition switch at the two 4-way connectors in the footwell, pulled out from behind the radio and there was negligible voltage drop there. So in my case at least I don't think the ignition switch is to blame.

If you're talking about the same connectors I think you are (battery 12 V on one set, switched 12 V on the other) then from memory the starter solenoid trigger is one of the inner two white wires on the 4-way connector, but not the one with a thin green wire coming from the same terminal. Assuming the same wiring colours!

[hvanman]

Thanks guys, seems it will be wiring related rather than motor then. I guess it would be best to go for the relay mod, I had not thought of that, as when it does work it normally turns over at a good speed, but a relay sounds much better. I will do some research on relay rating required etc and thanks for the wiring pointer Mat, at least it gives me somewhere to start....

[citsncycles]

I suspect Timex has had the same issue in the past, as the original wiring is in place, but a new set of wires has been routed to the starter.

When I get as far as the work on the window surround, I plan to replace the dash assembly with a better one I have, so will try to tackle the issue then - hopefully it'll give the rest of you an indication of where the problem is.

[Jaba]

Me too. My GTi refused to turn the starter once when it was very hot recently. Been ok ever since. I think this is just something that BXs do intermittently from time to time.
I have always thought that it is worthwhile to fit a push button switch for the starter motor when the problem becomes more than occasional.

[mat_fenwick]

The thought had crossed my mind too, but at least with the relay mounted in the injector pump it's stupidly easy (if a little embarrassing) to unplug one of the wires and touch it against the solenoid battery terminal.

[hvanman]

I did rather like the idea of an emergency bypass starter button somewhere, maybe with the relay normally operated from the output from the starter wire of the ignition switch for ease, but the bypass button with it's own separate feed to step in if it turns out to be poor contacts within the ignition switch itself, since there does seem to be this uncertainty as to where exactly the electrical breakdown occurs and the rather random nature of what will fix it (I was concerned this was going to be an expensive starter motor issue, but at least this fix will also bypass most of the under dash wring). I guess if it is just to operate the solenoid a relay suitable for air horns/headlights should be up to the job and then keep the cable runs to a minimum. Of course now I am back from France it has not done it once...

[mat_fenwick]

Surely an excuse (if one were needed) to go back to France and test out any modifications you make to the circuit?

I've seen a figure of 8 amps mentioned for the starter solenoid, but not measured it myself. I'm just using a standard 30 amp relay.

[KevR]

Funnily enough mine rarely plays up here in France, but always chooses to embarass me when I'm in the UK..... Although I've blamed the connecters behind the radio in the past, it's at least as likely to be one of those under battery tray I think.
I'm going to fit a relay very soon, as I'm sure it's the wiring not the motor/solenoid itself. As a temp measure I've added an extra wire to the solenoid terminal, which I can manually touch to the battery + if necessary - and it always spins straight over. When not in use the bare end of the wire slips into the insulation sheath on the main battery cable. Not ideal I know but I added the wire in the dark, by the side of the road, and haven't got round to sorting it out properly.

[citsncycles]

At the moment on the odd times it does it I just short the terminals on the solenoid with a big screwdriver. One peculiarity I did find particular to Timex was that the original wiring has only been disconnected at the starter end, and sometimes the issue was one of these shorting out until I tied it back out the way.