Glad To Be In Good Company, New member

Ref the solenoid spring perhaps being broken, surely this spring throws the starter out of engagement so a broken spring would tend to keep the starter gear engaged?

The solenoid engages the starter and holds it in engagement. After a series of starter changes I cannot believe that they have all suffered from solenoid faults so I would look for high resistance in the supply to the solenoid, a poor connection somewhere that gets hot as the current flows, increasing resistance until it no longer allows the holding current to flow. Try running a direct line from battery to solenoid and see if it then engages and stays in engagement, that should prove my theory.

Derek

Hi all,

The prematurely dis-engaging starter is surely a problem associated with undervoltage feed to the solenoid. When the key is first turned when cold the solenoid sees close to the battery voltage of 12v because the current is so lo0w and therefore it engages the starter. However, when the starter motor engages and takes 150-180 amps out of the battery then the terminal voltage falls below the threshold needed to keep the solenoid engaged. This is normal and happens on every car. However, the battery terminal voltage during cranking is normally enough to keep the solenoid engaged.

As a guess I'd say that there's a resistance in the circuit which travels through the ignition switch eventually feeding the solenoid. Normally the inevitable volt drop experienced during cranking isn't low enough to drop out the solenoid which is probably sized for a nominal voltage of 6v but survives because its on for such a short time. With an additional resistance in the solenoid feed line the voltage drops lower than the, say, 6v and it drops out.

For me, I'd do a thorough check of the whole circuit starting at the battery, going through the appropriate fuse, the ignition switch and the wiring to the solenoid. Somewhere in that circuit there's a duff connection.

Cheers

noz

Thank you Noz, for confirming my diagnosis!

Derek

Hi Derek,

Sorry, I should have read all the posts before replying. You're right of course.

Cheers

noz

Hi Noz,

Believe me, I'm only glad you agreed with me!

Derek

Noz - thanks very much. That does sound like the problem (unfortunately!). I had a replacement starter some time back but the problem has recurred. When the battery is charged overnight sometimes I'm lucky enough to get the starter to stay engaged long enough to start it. When warm no problem (not much anyway!). Any ideas where I should look?
And yes, its a 2.5 diesel estate - I'll get my signature sorted. Thanks everyone for your help.

Hi Hydractive,

Taking the problem back to basics there are many joints and cables between the battery (source of power) and solenoid on the starter (load). In addition there is a return path from the body of the starter through the earth strap(s) and back to the negative terminal of the battery. In theory any of the above can exhibit intermittent or permanent faults. In practice there are few which actually give any trouble. Firstly, heres the complete list:

There are 5 joints between the battery terminal and the ignition switch

Battery Terminal connector
2 way black connector - way 1 and 2 - located next to battery - thick wires
2 way black connector - way 1 and 2 - located in front of battery battery - thick wires
2 way black connector - way 1 and 2 - located on fuse/relay panel - thick wires
2 way black connector - way 1 and 2 - located on fuse/relay panel - thick wires

Ignition switch itself

There are 4 joints between the ignition switch and the starter motor

2 way brown connector - way 1 -located behind steering column
13 way white connector - way A7 - located beneath the glovebox
23 way black connector - way 6 - circular - located under slam panel in front of battery
1 way connector - colour unknown - located on solenoid on starter

As I said, in practice, only a few of these are likely to be the fault. In the main, cables are pretty robust and, apart from being chafed, they rarely give trouble. Focus should therefore be trained on the joints. Most of the joints inside the passenger section remain dry throughout their lives so are never subject to corrosion. Therefore the most likely culprits are those exposed to the elements. Those are:

Connection to solenoid itself
Thick black wire connectors in front of battery
Earth return from engine back to the body
Earth return back from the body to the battery negative terminal.

These connections are all exposed to the elements and liable to corrosion.

However, we can maybe rule out the thich wire feeds with a simple experiment. If the lights on the dash don't dim too much whilst the key is round at the start position then its likely these cables are OK. If the lights dim significantly then these cables (joints) are suspect.

Next is the earth return connections. Check with a meter between the earth terminal on the battery and the engine block during cranking. If the voltage rises above 0.5v then you have a high resistance between engine and battery negative terminal. If its stays low during cranking (or attempted cranking) then the earth return is likely to be OK.

If you're handy with a meter then a series of voltage drop experiments using the above info should lead you to the source of the fault.

Please come back with any other questions or test results.

cheers

noz

Hi All

From my experience the battery terminal clamps and the internal contacts in the ignition switch regularly cause trouble.
The original Citroen battery clamps streach with repeated use until they appear tight, supply everything in the car except the starter motor. I tend to move batteries around a lot and a little while ago nearly condemed 3 servicable batteries as not taking an adequate charge only to find that moving them to a car with a better set of clamps revived a "dead" battery enough to start that car. To get out of these difficulties I took the bolt out of each clamp and using a course hacksaw blade cut enough metal away to open up the clamp slot. This is not always a lasting fix as the Citroen soft metal clamps sometimes break in two. The much stronger "Halfords" type replacements (note positive & neg are different sizes/not interchangable) do not have a large enough hole for all the XM cables. The Citroen battery clamps are also only crimped onto the supply cables and this crimp can also work loose causing starting problems.
The internal contacts in the ignition switch are held tight in place by a single small screw and this has a habit of working loose. While all 4 types of switch are affected the Mk1 switches are the worst because there are 2 extra contacts and the contact block is a lot shorter than the Mk2 one so can flop about more as the screw gets loose. To check an ignition switch I leave the existing one with key insitu (for steering column lock) and just unplug the wires and plug in a known good switch.

Regards

XMexc

This post has been edited by xmexclusive on January 13, 2008 11:19 pm

I switched to those 'rigid' Halfords-type battery clamps when I had the 2.1 (now in citroenxm's care) and found they could accommodate the XM leads (at a squeeze!) after drilling them out a bit. Not ideal, but better than the 'stretchy' originals had become!

This post has been edited by mouseflakes on January 15, 2008 01:56 pm

Sorry to clutter up Introductions with such a long thread - I don't know how to change forums with the same thread!
Anyway, thank you very much Noz and everybody for so much help on the starter motor. Have begun to clean all terminals back from the battery. Am I right in thinking that the intercooler is just an air to air radiator so can be easily disconnected to gain access to the starter motor etc. Also, where does the battery earth cable go when it dives under the battery box - can I get the box out easily?!
Thanks again I'd be lost without you.

I used one of the 'gold' clamps from Halfrauds for the +ve, has a large hole for the main cable & a couple smaller ones for extra cables - aimed at the serious ICE modders, but did the job nicely.