Faulty Solenoid

[Tim Leech]

My lovely BX TZi auto when its been sat for a while sometimes takes a few turns of the key before it jumps in to life, I get a loud click, then on the 3rd or 4th attempt it cranks over fine and starts, its then fine for a short while but if I leave it for a few days etc it does it again.

It always eventually starts, but when it had the small "043" type battery it didnt which makes me think the solenoid at fault, since I fitted a higher ampage "diesel" battery its much less of a problem.

[Birotor]

Either gunged up or burnt power contact OR and this is the other possible cause does the engine itself or possibly the gear box have a copper braided earth connection these often break or are missing. This a regular problem on old 911s. The solenoid is of course a relay in itself but a further easily accessible relay on the line to the starter motor is never out of of place if you like fiddling with electrics... As a submariner I know DC and its maintenance problems and in Gibraltar Dockyard we had to get on with DC cranes and they were a constant pain with a heavy workload constantly changing contacts.... On my rally GS the head lamps main beam and the spots and fogs all have relays....

[mat_fenwick]

It's not necessarily the solenoid at fault, but could just be down to voltage drop through poor contacts in the ignition switch. With an newer/larger battery the voltage available will be higher so a small voltage drop will be less of a problem. Try turning the heater blower right down when trying to start, as that is the only item likely to be on when starting which also passes a heavy current through the ignition switch.

If that consistently improves things then my money would be on the ignition switch which could be sorted by replacement, or bypassing with a relay. Proof will be difficult without a multimeter.

EDIT - on an auto you have the starter inhibitor switch on the gearbox, which is another potential source of problems. I think it's unlikely to be a main starter feed or earth strap IF when it does turn over it does so nice and quickly.

[Tim Leech]

I always turn the fan off when I park up but will bear that in mind....Would like to try and avoid changing the ignition switch as all the locks "match".

The inhibitor switch seems ok, moving it from "P" to "N" makes no odds and it still clicks....

Where is the solenoid, just so I can take a look and see if the connectors are gunged up.

[themildbunch]

Are you 100% sure it hasn't already had the ignition modified with a relay?

My, albeit pretty knackered and abused, auto has had this and air horns too wired up with relays and a very bad earth bodged onto the inside front wing - I was getting very intermittent starting and a loud click but from the relay not the starter. A decent earth has fixed this permanently.

[citronut]

the solenoid is the smaller cylindrical device attached the the starter motor,

quite often the low tension/small lucar terminal on the solenoid ( top of starter ) just requires the connection cleaning up,

otherwise it could just be down to worn/sticking brush's in the starter motor,
next time it doesnt crank over bash the stater body ( not the solenoid ) with a bar whilst someone turns the ignition key

if it then cranks over it is almost certainly the brush's worn/sticking,

a relay is not required between the ignition switch and solenoid at its only feeding a low tension device ( the solenoid )

you should always switch everything off before turning the ignition off, as high current draw equipment will burn the ignition switch contacts if on whilst switching the ignition on or off,

also with the ignition switch in the starter position no other switched items are powered via the ignition switch, as the starter contacts are separate to the running contacts

regards malcolm

[Tim Leech]

Are you 100% sure it hasn't already had the ignition modified with a relay?

My, albeit pretty knackered and abused, auto has had this and air horns too wired up with relays and a very bad earth bodged onto the inside front wing - I was getting very intermittent starting and a loud click but from the relay not the starter. A decent earth has fixed this permanently.

Everything looks "factory" unlike the DTR which has relays everywhere!

[electrokid]

this is the other possible cause does the engine itself or possibly the gear box have a copper braided earth connection these often break or are missing.

I think it's unlikely to be a main starter feed or earth strap IF when it does turn over it does so nice and quickly.

Ok - this is an unusual circumstance - despite my 50 years experience of electronics engineering (which I'm quite good at ) I'm sure that Mat is much better at car electrics than I am. But on this occasion I have to disagree - but only to the extent of saying that the the earth strap between engine and bodywork should be carefully checked to make sure it is making a very good connection - before looking at other causes.

(There is one thing that is usually overlooked when considering starting issues - that while the engine is cranking, the alternator is producing output and therefore providing an electrical supply and if the engine is isolated that is at the engine only. For example, the BX is probably not so bad, but on a Granada, if the earth strap is missing and the starter is operated then even though the engine starts, the starter motor often continues to operate - power for the motor coming from the battery and power for the starter solenoid coming from the (disconnected from the battery and therfore unregulated) alternator. Due to the high currents involved in starting there can be some very odd effects the causes of which are not obvious)

Having said that - it does just sound like wear and tear Tim. I had to replace the starter motor because one of the brushes was completely worn away (the other 3 brushes also had very little 'meat' left of course). Before it failed completely it was intermittent - and I think is was in such a way that the wire from the 'missing' brush was also shorting out and causing very high current to flow during starting. The battery wasn't particularly good at the time but I'm sure the starter motor fault added to its woes and I needed to replace the battery at the same time as the starter motor.

When you hear the loud click that's obviously the starter solenoid operating - if the starter doesn't turn then it could be the solenoid contacts worn to the point of being intermittent - or it could be the brushgear intermittantly open circuit to the commutator, or it could even be an open circuit or intermittent coil on the starter motor's rotor.

A new and bigger battery will tend to 'cover up' where a component is getting worn - might still be an idea to at least remove the starter motor and have a look at the brushes - that will give you a good estimate of how much work the starter has done and whether it's due for replacement yet.

[Tim Leech]

Cheers chaps, for the little mileage I do and that the starter works 9 times out of 10 I will keep an eye on it for now, the car has A/C too which means even more pipe work in the way, I will keep a look out for a good value new starter motor as theres no point buying a used one.

Mines basically a 1.9GTi with an auto box and squidgy suspension, are the starters the same for most BX's? I expect the diesel ones are uprated?

[mat_fenwick]

I have to disagree

Ooh, fight!

I'll clarify - I can't see how if the earthing strap is the problem, why it would be intermittent. If it turns over well 9 times out of 10, that (to me) proves the fundamental fixed part of the circuit is OK. Hopefully you can understand my logic even if you disagree...

When you hear the loud click that's obviously the starter solenoid operating

Ah, I had assumed (possibly wrongly) that the click was the various ignition controlled relays opening as the key is moved to the starter position. I'm not sure either way whether you can hear the starter solenoid operating from the driver's seat, but if it is, that disproves my initial suggestion.

Probably the reason I suggested it is that I'm having the same problem at the moment! Very occasionally (it's happened maybe 5 times so far) I get nothing when I turn the key apart from relays clicking off. If I then turn off the heater blower (even though it does not operate when in the starter position), it cranks perfectly every time which seems too consistent to be coincidence.

I've not measured the current, but have heard it discussed that typically it's around 8-10 Amps continuously, peaking at something like 30-35 Amps for a very short period to actually start the solenoid moving. If that's actually true, it's not insignificant and ageing contacts could be a source of a voltage drop.

EDIT - I have a good petrol starter here, available for a few drinks. I don't know whether autos have a slightly uprated starter (they do on some cars) but the diesels definitely are, although an XUD starter will physically fit an XU engine.

[Tim Leech]

When the starter "clicks" its louder and more metallic in sound than a relay, more like a car with a flat battery.

Thanks for the offer Mat, I imagine as mine is a 1.9i, with an autobox and a/c it may need an uprated starter, so maybe a diesel one would be a good "upgrade" like the battery?.

GSF offer a couple of options, 1.1 kw or 1.8kw, which are both about £80 each if I return the old one, plus I get my trade discount so isnt so bad. The 1.8kw is also specified for a TD too.

[mat_fenwick]

OK, if the click is coming from the starter then ignore me talking about the switch. I probably thought of that first simply because it's on my mind at the moment! Starter is from a 1.9 Peugeot 205 GTi, but you'd need to check suitability if the starter is the problem and if you didn't go for a diesel one.

Incidentally, wear of the solenoid contacts seems to be a common problem on some cars - I've sorted a couple of Rover diesels with that issue (L Series? Early Freelander and 600) and replacement contacts are readily available on eBay. The fact that they aren’t listed for the XU suggests the problem isn't as common on PSA cars so brushes looks the most likely bet.

[Tim Leech]

Cheers Mat, I would just buy a new starter and have done with it, if the originals lasted 21 years with the little useage it will get in its dottage with me it should outlast the rest of it!

[Vanny]

Diesel starters spin SLOWER but with more torque, i assume due to windings, so in theory you shouldn't put a diesel starter on a petrol car.

That said i have only ever had a new style compact DIESEL starter on the valver, and my lord does it crank over fast! Frankly i would recommend fitting a compact diesel starter if you already have the diesel battery and your buying new. The old fat starters are archaic technology, and even the compact starter as fitted to the ZX onwards is pretty antique these days.

BUT fitting a new starter wont help if the earth from gearbox to battery is shot. Citroen spent £3500 on my dads BX to learn this lesson!

[citronut]

dont go replacing the battery till you prove the starter is not at fault which i very much doubt,
as i said erlier try bashing the starter body whilst someone turns the key to the starter position,

if the starter cranks over doing this it is just the brush's worn down/sticking


regards malcolm