Sticky starter - new solenoid needed?

[Geoffrey Gould]

Hi there is a cure for the non working solenoid situation when the starter and solenoid is in reasonable condition ( and it's not a bad earth or battery connection etc.) the problem is French wiring and the voltage drop so that there is just not quite enough to fire the solenoid. The answer is to fit a relay that is fired by the original supply to the solenoid and then a supply from the battery through the relay to the solenoid. Using some reasonable cable 28 amp should be ample.Sorry.
It's really just another addition of the 10 volts to the headlamps, if they are relayed then the difference in illumination is amazing.
Cheers.
G.

[KevR]

I obviously see why fitting relays and new feeds for headlights is a good idea, but surely the solenoid itself doesn't actually draw enough current for that to be an issue. The solenoid is just a relay itself, after all, albeit a heavier duty version.

[mat_fenwick]

I would have thought that too, but my problem is still there occasionally, and it does seem to be related to battery voltage as if I leave a 12V fridge on, it seems more likely to do it. Also yesterday morning it started perfectly to move it to give a jump lead boost to prime the fuel system of the silver one - but after a couple of minutes cranking the silver one (engine off on the red one) it wouldn't start. Rest the battery a few minutes and it cranks fine.

What I should have done is measure the voltage at the starter solenoid trigger before suspecting a dirty solenoid contact (I thought that as I have previously spilt oil over the starter a couple of times). I'll try and measure the voltage next time it happens but think that a relay would probably be a wise idea. If it is voltage drop it could be in the ignition switch contacts, or possibly the 7 way multi-connector above the gearbox.

[KevR]

Is that the brown multi-connector? Always seems to be manky and corroded. I keep meaning to take one apart to see if you can get new terminals – the block itself is the same as one or two that connect up near the fusebox and so keep nice and clean, so it would be good to replace the old one with a nice new one and new terminals. I know you can get generic multiconnectors but they tend to be a lot chunkier - would be nice to keep the original type.

[mat_fenwick]

Could be white rather than brown, but not 100%. The reason that springs to mind (apart from the fact it gets manky) is that earlier this year I had trouble with the reversing lights, which are the only other connector in this block which carries a significant current.

It was a bit of a puzzle for me at first, as I got ~12V at the rear lights when I took the bulbs out. It was only when I checked for voltage with the bulbs in that I realised there was a voltage drop somewhere. It was not a problem with the male/female parts of the connector, but rather where the cable was spliced (like a Scotchlock) into the vehicle side of the loom. Not a great design, so I'll probably replace that with a Superseal style of connector.

[KevR]

The Superseal was the other option - lovely things, but pricey...

[mat_fenwick]

Biggest Superseal I can find is a 6 way, so no good there anyway. I have an extra wire to the oil pressure sender hence ideally would be after an 8 way, so the large version of the 250 series looks to be the best bet. And £12 for a pair doesn't seem too bad.

Not a great design

Thinking about it, it's lasted longer than the car's planned lifespan, so you could argue it is designed well. Anything more durable would have been wasteful over-engineering, at least in Citroen's view.

[Geoffrey Gould]

Well it may not seem a great deal of current to draw the solenoid in but it's the sudden initial 'gulp' of current that sometimes is just not quite enough with the battery standing overnight and if a diesel then the 80 or so amps of the glow plugs when they start off even if they drop to about 20 amps ( if I remember correctly, I did measure it once.) Plus the only just good enough wire gauge when new, the 'ignition switch' contacts and other joins, the wire turns a lovely (not) black with corrosion and it all adds up, an analog meter will be very revealing and a DMM less so because by the time the DMM has sorted it's reading out the initial high demand will have passed.
I cant remember the pull in demand for the solenoid but it was surprisingly large. (15 amp?) , a quick snap in for the contacts and of course if pr-engaged moving the fork to engage the gear to flywheel teeth.
A relay will ensure that virtually all the battery voltage will be available at the solenoid. Not a bad thing.
Cheers.
G.

[KevR]

I cant remember the pull in demand for the solenoid but it was surprisingly large. (15 amp?)

Blimey, that is a lot more than I would have thought. An extra relay it is then! One day, when I get round to it.

[citsncycles]

I think it's one for my job list too.

[mat_fenwick]

It's happened a few more times to me now, so I got the meter out and measured the voltage between the positive battery terminal and the solenoid trigger terminal (whilst still connected). To my surprise there was over 5.5V drop from battery voltage!
I've now fitted a relay, but may later investigate where the high resistance is.

[Geoffrey Gould]

Hello Mat I have had the actual wire itself turn into a resistance, in this case the short length from the stop solenoid, clean terminals at both ends but enough voltage drop to stop the solenoid pulling in. Although I said it was a 'cure' for the starter solenoid problem it in all honesty only masking a fault but one that seems to be happening a fair bit, it does seem to be that it reaches a point that it does not get worse, when asked to provide the relatively tiny demand of a standard relay.
The interesting question is " has anyone reached the point when a standard relay has failed to operate."
Cheers.
G.

[electrokid]

over 5.5V drop

My my - that's quite a lot Mat

I don't think it would be particularly easy to measure mine - it's only on for about half a second !

I have had the actual wire itself turn into a resistance

And I bet the little b***er was green as well

[hvanman]

I had this same problem of intermitant lack of any response when turning the ignition key. I removed the iginition switch assembly and swapped for a used one and also while doing this noticed that the terminals in the white connector behind the radio were showing some corrosion. I cleaned these and with the second iginition switch have had no more problems. Simon

[mat_fenwick]

I have yet to properly solve the problem, but for now I've cured the symptoms with the relay - no more issues since. I do suspect some voltage drop across the ignition switch, as when I brake at night I can see the instruments dim slightly.

I don't think it would be particularly easy to measure mine - it's only on for about half a second !

That was the difficulty in diagnosing the problem - when the starter is working correctly you're trying to measure a brief transient voltage. So I had to wait until it reoccurred to be able to measure anything meaningful.