BXProject

[mat_the_cat]

Stupid question time: where is the glow plug relay on ABS equipped BXs?

And if anyone knows what tools are required to remove the Xantia relay I'd be very grateful - there is one dumped in a quarry around here that I may go and pillage - but it is a bit of a walk so bringing only the right tools would be an advantage...

[Vanny]

same place it is on a none ABS BX

You need a 10mm socket and a set of side cutters to get one off a xantia, unless you need the cross link cable (which you probably do) in which case you'll additionally need a 8mm socket.

If your clever, the 'heavy' cable to the relay from the battery distribution panel can be unplugged.

[mat_the_cat]

If your clever

That's me out then...

I'll get the whole lot from the Xantia, I'm sure it'll make sense when I see it. There may be 2 different locations on the BX though, the non ABS BXs I've seen (only a couple) have had the relay on the inner wing where the ABS pump sits. The only area I can think of is by the rad on the battery side, I'll have a look later.

[Philhod]

The diesely ones are on the inner n/s wing 1/2 way along up under the bonnet gutter.

[Vanny]

The diesely ones are on the inner n/s wing 1/2 way along up under the bonnet gutter.

also known as

where the ABS pump sits

But a little bit further forward me thinks.


Though i realise i dont think i've ever seen a diesel with ABS, or certainly not noted the relay location

[mat_the_cat]

It was between the airbox and the radiator, inside a plastic bag that has kept it pristine! So much so that if I was devious, I could sell it as brand new....
Although finding it wasn't helped by the dog licking my face every time I bent down to work on it, bloody thing wouldn't even hold my torch for me.

[mat_the_cat]

I've had a bit of an idea - the BX relay keeps the glow plugs on, for say 30 seconds, if you don't try and start the engine. When you crank they engine they go off and stay off. So if I disconnected the wire to the relay from the starter, they would also stay on for a while after the engine starts. The only downside to that I can see is that they would also be on when the engine is cranking which would put extra stress on the battery, I presume the Xantia relay would cut the power when cranking. Anyone see any other drawbacks? I'll probably get the Xantia one anyway and have a bit of a play...

[Vanny]

Hmm, that doesn't sound right. The post heat is based on temperature, my understanding is that the Xantia relay uses this to keep the plugs lit. If the BX relay is staying on, then it is the pre heat timer. When you put the key to 'GLOW' the timer starts, its a fixed time, the light goes out on the dash dependant on the ambient temp sensor (in the relay housing), this is the reason you should give a full 10 to 15 seconds in coldweathe regardless of the light going out or not. This is NOT the same as post heat.

I'd be half tempted to suggest adding a button for post heat (live to 'Ign_On' on the relay) and punt it on for longer that way. Or fit the other relay.


Though i'm not convinced about what the cause of your piss poor running is. I wonder if one of the mix chambers is cracked, and hence the heating is sealing up the crack?

[jonathan_dyane]

Strangely my father's Xantia TD was never a brilliant starter, always fluffed and coughed to begin with, despite running beautifully once running. The glowplugs were perfect, and there were no apparent air leaks.

My mate Jason has just bought a 60000 mile Xantia TD (which I am supposed to be servicing this afternoon) which has exactly the same affliction...

[mat_the_cat]

Hmm, that doesn't sound right. The post heat is based on temperature, my understanding is that the Xantia relay uses this to keep the plugs lit. If the BX relay is staying on, then it is the pre heat timer. When you put the key to 'GLOW' the timer starts, its a fixed time, the light goes out on the dash dependant on the ambient temp sensor (in the relay housing)

Ahhh, looks like mine is different to the system you speak of. There is no temperature switch (or wiring for it) on the filter housing. (The Xantia lump *may* have had one but it's now been removed). So I get the glow plug light coming on for a fixed period of time, and the glow plugs themselves coming on for a longer fixed period of time unless the engine is cranked. With the Xantia relay, unless I fit a temperature switch, I will always get post heat for 3 minutes or so after the engine starts, even when the engine is hot. Which seems wasteful although probably not much of an issue as I rarely do hot starts.

Though i'm not convinced about what the cause of your piss poor running is. I wonder if one of the mix chambers is cracked, and hence the heating is sealing up the crack?

I've changed the head since which made no difference. The old one did have cracked pre chambers, but non visible on the replacement (not ruling it out but probably unlikely). The puzzling thing is that the engine whilst in the Xantia had no problems since and my Dad had it from 6 months old, and as soon as it was put in the BX the problems started (even before fuel pump adjustment). Once I've sorted out the relay (and I probably will go for the Xantia one with a temp switch) then we'll see how things look. It would certainly be worth checking the timing I think.

[Vanny]

no temperature switch

Air temperature, not water temperature. It is internal to the relay supposedly.

[mat_the_cat]

It is internal to the relay supposedly.

As you did put in your post but I read it as filter housing.
Got the Xantia relay now, and would have the temperature switch from the fuel filter housing if I had thought to bring an adjustable with me. Spot on with the other tools though.

[Vanny]

Totally forgot about the water one to be honest, my understanding is that if its not connected then the post heat relay stays engaged for the maximum length of time. Its a relatively standard citroen temp guage (green or red band i believe) so you should not struggle to get another.

[Philhod]

So, if I'm following this correctly and you don't connect to the thermostat housing, the post heat will stay on for a finite period after starting? Which is what you wanted wasn't it??

OK so it might shorten the plug life but instant smoke free starts FTW.

[Vanny]

Cross purposes Phil, BX one's dont post heat, this new fangled xantia one does post heat.

[mat_the_cat]

Looking at the wiring diagram it seems to be a switch which is open above a certain temperature rather than a gauge sender - if this is the case I may need to wire in the ignition feed in to 2 terminals on the Xantia relay. You were right about the BX relay - it looks to have an NTC thermistor on the circuit board inside.

[Philhod]

Bye for now

[mat_the_cat]

Maybe just for you Phil we should start a thread about rotary dial telephones, valve elctronics and gramophones?

Hopefully this saga is finished now; I've wired in the Xantia relay and the starting is spot on. Was very scorchio today so the true test will be on a cold morning. After looking at the Xantia wiring diagram again I've seen that pin 2 is earthed via a relay which is closed when the temperature switch is hot and/or the throttle is opened beyond a certain point. If I leave this wire unconnected I get post heat for about 15-20 seconds, if I earth this wire I get post heat for a few minutes. I've temporarily connected it to the battery negative terminal for now, but once I go back and get the temperature sensor I'll just wire it direct to that.
Anbody else need Xantia bits? (Carryable that is, I'm not dragging an engine for miles!)

[Philhod]

Would make no difference to me Mat, if it has wires, printed circuits, in fact circuits of any kind, sensors, resistors, I have no interest coz it's not logical.

Take my phone, I was converted to Virgin cable a month back and because I now plug the phone to a new box all my extensions are cut off.
So, logically if I disconnect the incoming wires from the BT box, stick a double outlet on the new box and use an plug in cable from new box to old. simples.....didn't work

Chuck the double socket away. cut off the plug in's, connect direct from socket to socket.....
...,everything works!!!! Just nooooo logic.

Err I may have got which wire wrong, but that was what I was trying to suggest that leaving whichever off would give a good post heat and solve your problem.....ish.

[mat_the_cat]

Yeah, got what you were trying to say Phil. It may have been OK with just the 15 seconds or so of post heat but when I get chance I'll put the temp switch in. Or put in a little manual switch to have summer and winter post heat settings!

I think your problem with the phone sockets may be due to master and slave sockets being different, and it sounds like you were tring to use the old BT master as a slave...anyway sorted now.