Starter Fix..Particularly with inhibitor on autos

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Starter Fix..Particularly with inhibitor on autos

Post by m_2975 »

Hi Guys,

As you may know my family used to have a Citroën Dealership here in Australia. We had many a BX come in with starting problems. Manuals and Autos.
All we ever did was make a simple modification to the starter circuit and it fixed it all....of course until the brushes and bushes in the starter go!

This mod is done in the engine bay and is typically mounted next to the LHM reservior, close to the alternator.
Simply wire up a standard relay (with open circuit at rest) and unplug the small wire that pushes onto the top of the starter. Use this as your relay supply power (provides the signal to close the circuit). Connect the other side of the relay's power circuit to the body (on a bolt or something that makes electrical contact). Get a decent thickness wire and run it directly from the battery or the terminal on the alternator to one side of the switched input on the relay. Connect the other side of that switched input on the relay back onto that plug on the starter.

There you have it!
I hope it makes sense. If it doesn't let me know and I can draw a diagram.

Basically what happens is that over time your ignition switch gets worn, particularly the start position as it carries the load when the starter is running. This results in increased resistance between the battery and the starter meaning that the starter should be getting 12 volts but may be ending up with 9 or 8 volts. This may be enough for the starter for a while to get moving but the starter's brushes also wear out and this then means that again there is not enough power to drive the starter motor.

What the relay does is do the work instead of the ignition switch. All the ignition switch does is give a signal to the relay to make contact from the battery to the starter. This gives the starter all the juice that the battery has.

The inhibitor switch in Auto's actually makes the situation worse, but in fact it isn't it's fault. It too results in resistance loss and therefore the starter doesn't have enough juice to turn over. The relay will fix this.

Has worked on every single BX that it's been done to. All of ours have it.

A definate recommendation to those who don't have it as it saves wear and tear on the ignition switch.

As I said if you need details let me know.

My Cars:
'93 BX 19GTi Sedan 5M
'89 BX 19TRI Estate 5M
'89 AX GT(With EFI) 2door 5M
In the Family:
'74 SM IE (Fully Restored) 5M
'90 BX 19TRI122 Sedan 4A
'02 Xantia Exclusive Sedan 4AA
'06 C5 2.2HDi Estate 6A

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Post by Cornishbx16v »

The relay in the starter circuit is a very common mod on most cit and pug engines!
i know many of the 16v owners have the said mod and also a lot of the owners on the pug sport sites have too as thats where i first heard of it about 8 years ago!

After all I AM CORNISH!!!!

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Post by richard »

I done that mod on mine after I replaced the ignition switch about 8 years ago. I was told by my local Cit specialist to do this as the current taken by the starter solenoid is a little much for the switch long term!

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Post by Ian_Fearn »

Any chance of making this a bit clearer for somebody who has NEVER wired up a relay before??? Our auto has given up.

Over and out from me

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Post by kiwi »

Since I just replaced the ignition switch on my BX beacuse it jammed that could be useful to stop wear on the starter motor?

Totally un citreon related next door neighbour on his Ford Telstar has the same problem you described. Same think I assume work on his?
1991 BX19 TZS 04/01/91 (Deceased)
1990 BX19 TRS 27/10/89 (Reborn)
1992 BX19 TXD (Ex UK - K 744 SDF) 15/06/92
1990 BX19 TZS Auto 06/11/1989
1992 BX TZD Turbo Estate (Ex UK) 1/07/91

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Post by prm »


A relay is usually a means of switching a high amperage circuit with a low operating signal.
Relay units come with various combinations of connections; most of the BX’s have 4 or 5 spades, on the base

2 connections- usually opposite each other, are the relay coil, with a resistance between these terminals, in the region of 60-180 mA, these are connected to the switching circuit –say ignition switch. The remainder are the operating/switching circuits.
4 spade units - 2 are coil and 2 are the operating circuit, on/off - say starter solenoid.
5 spade units – 2 are coil, and the other 3 connections operate ether with an on, or off application.

Sorry to run through basics if you are familiar with relays.

The starter solenoid supply from the ignition switch should?? be, the yellow wire on the 8 way ? white or clear, multi-pin connector, adjacent to the inner wing in the battery negative lead area.

A variation on Michael’s mod, is to fit an additional BX type relay on the bulkhead relay rail. Cut the yellow wire ether side of the block connector, extend the supply from the ignition switch to relay coil –No 1 terminal, then find any suitable earth point for relay coil No 2 terminal - the main chassis earth point near the block connector is ideal.

Extend the solenoid supply wire to No 5 relay terminal - normally open with No 3.
Locate a permanent battery supply, and connect to relay terminal No 3.
There maybe a spare spade connect inside the black block connector, on the positive battery lead to avoid a direct connection to the battery.

Found worn ignition switch contacts and corroded wiring connections have caused problems by reducing the supply voltage to the starter solenoid and failing to engage.

A drawing of BX wiring mods that may help with relays, with a variation on the starter/ ignition circuit. ... Mods_1.xps

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Post by cacaolat »

hey it sounds like my auto could benefit from that....I have changed starter motors twice already...(luckily one was done free under warranty)
but I don't even know how a relay looks like...
former BX 16 TGS Meteor Auto owner. No space or time to do own repairs. My BX is now owned by another member of this forum.

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Post by Mike E (uk) »

I think the problem with starter solonoids is that if they are driven with insufficient voltage, they do not switch fast enough which causes extra wear on the solonoid contacts through arcing. The starter switch also wears out too as mentioned.

The current for the ignition coil also passes through the key switch,
so I have wired mine with a relay in a similar way to the starter mod.
It reduces wear on the switch, and must improve the spark.

Adding relays for the headlamps is worthwhile too.

la BX 16 soupapes: sachez apprecier avec moderation.

It might be clever now, but it won't be in the morning!