BX Time - '89 16v project

This is a common BX problem in that the low temp contacts in the temperature sensor take the full current of the fans in series connection and eventually it doesn't work on slow series speed anymore. I used to put in an extra relay switched by the lower thermal contact, to carry the fan current so the replacement thermal sensor would last much longer.

Another problem with this system occurs when one fan runs out of brushes. This causes the series fan setting to fail completely and only one fan to work on full speed. This is not so much of a problem on the BX as the brushes seem to last well, but it does seem to happen to most Xantias at some stage in their life.

Cheers Ken
 
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Low speed is working fine Ken but something is a bit wonky with the high speed. Both fans work fine if the fan 2 high speed relay is removed but not when the relay is connected.

Another relay has been added on the far left of the relay bracket and it's tied into the A/C trinary switch and slow speed fan relay.
 
looks like fuse two was replaced by TARZAN when it kept blowing ,id be checking that out pronto, what douse that fuse protect ,? if its the thermo fans ,it may have fried the wiring resulting in the addition of the extra relay you have found ,who knows
 
The switch over relay from low to high speed cops a real hiding, especially if it is not good at breaking the series connection before it makes its new connection. Perhaps you should replace this relay.

Cheers, Ken
 
It's fuse 2 which supposedly controls the instrument panel lighting and A/C. A proper fuse is definitely on the cards.

Poking around the engine bay revealed a few strange things. This violet connector by the AFM
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This black connector coming out of the wiring to the coil
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This coolant hose coming from the thermostat housing plugged with a screw
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And it looks like the driver's front strut top is weeping
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Any help with what the electrical connectors are for and that coolant line would be helpful.
 
I will have a look at one of ours tomorrow to see if I can shed any light on these discoveries.

Cheers, Ken
 
Hi Faulksy,

I have had a look at my 16V with missing engine/gearbox and it has the green wire with mauve connector coming off near the connector for the airflow sensor, it only has 4 wires going to the coil and no extra green wire with black connector and that coolant hose is sitting on the bleed valve connector of the thermostat housing. So unscrew the screw when bleeding the coolant system.

I suspect that the extra wire from the coil system is joined to one of the coil wires so as to allow the coil waveform to be checked using a oscilloscope. Our 16V with an engine has one of these wires and it seems to run back in the loom towards the coil connector.

The quite late model 16V with engine doesn't have the green wire with mauve connector coming off the air flow meter loom.

I hope this helps.

Cheers, Ken
 
Thanks for that Ken, its very helpful. Good to know that those connectors should be there and not connected.

Is the hose on the thermostat housing original or do you reckon someone has added it?

My understanding is that the later 16V use a different version of the Motronic injection system which might explain the slight difference in wiring.
 
There would have been a somewhat fragile hex screw there that you unscrew a bit to let any air and coolant come through an internal passage and out of the system. They were often very difficult to get to seal well. We started using bodok washers to get them to seal well. I would think that someone has broken the top of the thread, snapped the head off the screw or lost it, so has replaced it with what you have now. Those housings are also very easy to crack at the bottom of the bleeder stalk and then they leak all the time so I would leave well alone there and just use it how it is.

The 16V do use a version of the Motronic 1.3 to manage the closed loop oxygen sensor controlled catalytic converter, EFI and Ignition but it has a knock sensor and extra circuitry added and of course different software in its EPROM.

Peter T has had extensive experience in modding these engines to bring their performance back up to exceed that of the euro versions. One of our 16V has a Peter T version engine that Dave rebuilt with a decked block and liners (to bring the compression up) and a Stage 1 inlet cam. It was initially amazing to drive - it just didn't notice uphills at all, but when we moved it to another car and changed the cambelt, it seemed to lose some of its sparkle - we need Dave to come over and get the valve timing right next time we change the cambelt.

Cheers, Ken
 
I’ve run into a problem with the clutch pedal. When getting out of the car the other day I managed to get my foot hooked under the clutch pedal and lift it up. Apparently this causes the cable to become unhooked from the pedal. So, the pedals had to come out which required laying updsideown across both front seat with my head in the drivers footwell.

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The 4 fasteners came out easily enough and the cable was hooked back on to the pedal

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to get enough slack I had to wind out the adjuster at the clutch fork and take the cable out of the arm. Herein lies the problem. It’s all back together but the pedal is sitting very close to the firewall and the clutch won’t disengage when the pedal is pressed. I’ve adjusted the cable to the maximum and it hasn’t helped.

Does anyone have any tips for fitting and adjusting the clutch cable?
 
Well you won't do that again. I have not heard of that happening before but note to self to keep my feet tidy when exiting the car. This is one of the less nice bits of the BX design.

You need to get extra cable inner length so that the pedal can sit a bit higher. From memory, the cable end connector at the pedal needs to be bent towards the back of the car so it will slide down all the way into the slot on the pedal engagement point. Maybe this is sitting at the top of the slot or is jammed half way down. Also, the white collar on the cable outer collar has to sit snugly in the 7/8 ring retainer bit of the pedal setup you can see in your picture. It does look a bit distorted in the pic, so maybe it is sitting low and reducing the overall length of the cable. Is that black bit sitting on the cable above the white outer retainer the ring that is supposed to lock the white bit into the 7/8 ring? If so cut it off to get a bit more cable length.

At least you have a proper release fork and arm on a 16V, not the right angle arm (that fatigues) and transfer pin (that drops out onto the road and gets lost when you break a cable) that the 8V car had on the bell housing end.

The other problem with the BX clutches is that the throw out bearing presses gently on the back of the diaphragm spring on the clutch plate all the time. If the bearing end is narrow, it can wear a groove in the spring fingers that leads to trapping of the bearing ring and great difficulty in releasing the clutch properly. Then all the bits start to bend and fatigue. I bought a BX with this problem and it took me quite a while to work out what the problem was. In fact I didn't work it out until I renewed the clutch assembly after having the to get the pedal box re-welded and strengthened.

Happy Sunday Morning, Cheers, Ken
 
Thanks for that Ken, really helpful. We were debating if the white collar needed to somehow engage with the pedal assembly but couldn’t work out how. Looks like I have to take the whole lot out again and have another go
 
Problem solved! Turns out that I just needed to wind a lot more of the adjuster through the clutch release arm. I wasn;t expecting to have to wind 60mm of adjuster through the arm.
 
Random question for this week, does anybody know where the interior lighting timer lives?

The interior lights don’t come on when any of the doors are opened but come on when you use the switches on the lamps themselves.
 
Have you tried unscrewing one of the door switches and grounding the wire on the back to see if the interior lights come on?

Also check to see if there is any voltage between the wire and chassis with a multimeter. In the meantime, I will look at a manual for you to find out about the light controller.

Cheers, Ken
 
Thanks Ken. The lamps themselves work using the switches on the lamps so they’re getting power.

I’ve got the wiring diagrams so can see where the light controller is in the circuit. It between the lamps and the door switches. The diagrams don’t show where it’s physically located on the car though.

It’s weird that none of the 4 door switches are working. I’ll break out the multimeter and report back.
 
faulksy said:
Thanks Ken. The lamps themselves work using the switches on the lamps so they’re getting power.

I’ve got the wiring diagrams so can see where the light controller is in the circuit. It between the lamps and the door switches. The diagrams don’t show where it’s physically located on the car though.

It’s weird that none of the 4 door switches are working. I’ll break out the multimeter and report back.
Click to expand...
I still think Ken’s point of checking the door switches first is correct
 
Hi Faulksy,

Unfortunately my copy of SEDRE circuit diagrams only goes back as far as the ZX model. So I have to defer to the Haynes Manual for the circuits for post 1987 models. I see item 92 on the diagram 6 circuit IX which is identified as the interior light controller and the only clue I can give you is that it is connected to Loom T which is for the instrument panel. So maybe it is just below the binnacle or inside there for you to find after you take out the instrument cluster. I suggest you go looking for it when you have another reason to take out the instrument cluster.

I haven't had to tackle this on a BX so I'm not sure where it is but I have fixed a failed one on a CX turbo. Someone had mixed up the leads to the interior light so that 12 volts was connecting through the light controller to chassis. Needless to say, the power transistor had gone open circuit and it all came good with the correct wiring and a replacement power transistor.

Cheers, Ken

PS By the way, I did have a look at the 16V that is resting on our garden (under a hail cover at present) for a intake air pipe that goes to the air cleaner. It is missing on this one too. I reckon they must be a pretty rare find these days.
 
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