I'll get round to it at some point - XM MOT Finally Passed!

[Rust Collector]

Well, I finally have some good news.

Today I decided to back probe the power connector to the ECU; 2.5v anaemic bolts were present. It was showing battery voltage when disconnected, so it appeared to be an issue with the circuit under load.

I soldered some wires to a 5w bulb to make a test lamp, removed the pin from the connector and tested it with the lamp; this confirmed that there was no power at all under load.

I dutifully set about measuring the resistance between the fuse box and the ECU connector.

Yep, that’ll do it.

Sniffing around the fuse box revealed that I was not the first one in here.

Hmm…

I decided to pull the fuse box out, and test the wiring from connector to connector.

Whilst removing the fuse box, I was reminded that I ducking hate removing fuse boxes.

When I began refitting it later, I was reminded that I fucking hate refitting them even more.

This bracket was flapping in the breeze and bent, which is possibly why I can’t access the top row of uses normally. I’ve hammered it flat and have realised that refitting this is awful too.

It’s definitely been one of those ‘it has to get worse before it can get better’ sessions.

This revealed that the previous attack on the fuse box had been a result of installing the tow bar electrics, the indicator relay had to be replaced for a 4 pin relay.

To follow the loom out the bulkhead, I had to remove all of these bastard hoses and the LHM tank again; at least they’re fairly free moving as a result of me being in here a few months ago.

I then got distracted, and found the ECU that controls the cooling fans.

More on that in a bit…

Tracing through the wiring loom for the main ABS power feed led me to this connector - it looks ok visually, but appears to have broken down internally.

I didn’t have a proper connector spare, so did a quick proof of concept mock up with crimp connectors.

This got the ABS ECU to power on and self test, but the lamp stayed on. I then read the codes, cleared them and cycled the ignition:

Success! The light came on, the ECU did the self test, and the light went out. I’ve ordered some waterproof connectors and a new terminal crimping tool, so I can do a proper-ish repair.

Shame that I’ve pretty much literally had to tear the whole car apart to get here.

Moving on to the cooling fan issue, it turns out that the ECU for these is sealed. Luckily I own a hacksaw, and give zero fucks about anything on this car that already doesn’t work - it can’t get any more broken, right?!

After cutting the link faceplate off, I was able to pry the guts out of it with a couple of picks. They did not want you getting in here apparently.

Anyway, I liked what I saw: even a moron like me can figure out that burnt bits on a circuit board are probably broken.

That diode was immolated for its sins, apparently.

I can’t find a matching part number, so I reckon I’m going to be doing an arse load of soldering in the near future. I’ve tested that diode, and obviously it’s mega fucked. I’ve tested the others, and one is definitely bad and one or two read a bit high. The capacitors all seemed ok, so that’s something at least.

Did I mention that I’m really not looking forward to putting all of this back together again?

Whilst I’m pleased that it looks like the two main electrical problems are now sorted, this does mean it’s nearly time to try and remember what order the whole car has to go back together in…

[GagaStan]

1 hour ago, Rust Collector said:

I can’t find a matching part number

This fan control box looks very similar to the unit used on earlier 306s and Xsaras - could be worth digging around at a scrapyard for one? They're located just in front of the passenger side wheel arch.

[High Jetter]

1 hour ago, Rust Collector said:

Well, I finally have some good news.

Today I decided to back probe the power connector to the ECU; 2.5v anaemic bolts were present. It was showing battery voltage when disconnected, so it appeared to be an issue with the circuit under load.

I soldered some wires to a 5w bulb to make a test lamp, removed the pin from the connector and tested it with the lamp; this confirmed that there was no power at all under load.

I dutifully set about measuring the resistance between the fuse box and the ECU connector.

Yep, that’ll do it.

Sniffing around the fuse box revealed that I was not the first one in here.

Hmm…

I decided to pull the fuse box out, and test the wiring from connector to connector.

Whilst removing the fuse box, I was reminded that I ducking hate removing fuse boxes.

When I began refitting it later, I was reminded that I fucking hate refitting them even more.

This bracket was flapping in the breeze and bent, which is possibly why I can’t access the top row of uses normally. I’ve hammered it flat and have realised that refitting this is awful too.

It’s definitely been one of those ‘it has to get worse before it can get better’ sessions.

This revealed that the previous attack on the fuse box had been a result of installing the tow bar electrics, the indicator relay had to be replaced for a 4 pin relay.

To follow the loom out the bulkhead, I had to remove all of these bastard hoses and the LHM tank again; at least they’re fairly free moving as a result of me being in here a few months ago.

I then got distracted, and found the ECU that controls the cooling fans.

More on that in a bit…

Tracing through the wiring loom for the main ABS power feed led me to this connector - it looks ok visually, but appears to have broken down internally.

I didn’t have a proper connector spare, so did a quick proof of concept mock up with crimp connectors.

This got the ABS ECU to power on and self test, but the lamp stayed on. I then read the codes, cleared them and cycled the ignition:

Success! The light came on, the ECU did the self test, and the light went out. I’ve ordered some waterproof connectors and a new terminal crimping tool, so I can do a proper-ish repair.

Shame that I’ve pretty much literally had to tear the whole car apart to get here.

Moving on to the cooling fan issue, it turns out that the ECU for these is sealed. Luckily I own a hacksaw, and give zero fucks about anything on this car that already doesn’t work - it can’t get any more broken, right?!

After cutting the link faceplate off, I was able to pry the guts out of it with a couple of picks. They did not want you getting in here apparently.

Anyway, I liked what I saw: even a moron like me can figure out that burnt bits on a circuit board are probably broken.

That diode was immolated for its sins, apparently.

I can’t find a matching part number, so I reckon I’m going to be doing an arse load of soldering in the near future. I’ve tested that diode, and obviously it’s mega fucked. I’ve tested the others, and one is definitely bad and one or two read a bit high. The capacitors all seemed ok, so that’s something at least.

Did I mention that I’m really not looking forward to putting all of this back together again?

Whilst I’m pleased that it looks like the two main electrical problems are now sorted, this does mean it’s nearly time to try and remember what order the whole car has to go back together in…

Proper work. Hope you're enjoying a beer now.

[rob88h]

2 hours ago, Rust Collector said:

That footwell 😆 - it’s an Auto Shite work of art. 
(Good work, impressive tenacious diagnostics going on here)

[Matty]

I do hope you get somewhere with this. You bloody deserve to.

[Rust Collector]

8 hours ago, GagaStan said:

This fan control box looks very similar to the unit used on earlier 306s and Xsaras - could be worth digging around at a scrapyard for one? They're located just in front of the passenger side wheel arch.

I have seen some for sale from other cars, but I’m aware that there are differences in the built in logic regarding the temps that the fans run at based on car and engine fitted - so really I’d like a unit from a 2.1td XM. I reckon with a bit of patience I can potentially repair this one one though.

8 hours ago, rob88h said:

That footwell 😆 - it’s an Auto Shite work of art. 
(Good work, impressive tenacious diagnostics going on here)

I’ve been using the organisational method of ‘throw it in the footwell, because you’ll need it to put it back together again’. I can’t recommend it 😂

7 hours ago, Matty said:

I do hope you get somewhere with this. You bloody deserve to.

Thanks mate - I’m looking forward to getting it put back together and having a (hopefully) more functional car than I had before this work started.

[Rust Collector]

8 hours ago, High Jetter said:

Proper work. Hope you're enjoying a beer now.

I was ahead of the curve, and had a gin and tonic or two whilst getting the work done 😂

[Split_Pin]

Absolute Biblical levels of patience there. I'm like this:

..when it comes to wiring and electrics.

Very impressive man.

[Sigmund Fraud]

50 minutes ago, Rust Collector said:

I was ahead of the curve, and had a gin and tonic or two whilst getting the work done 😂

If AS ever publishes a workshop manual, I reckon it should have G&T ratings instead of the quaint Haynes spanner ratings.

"Yeah, that was a proper five G&T job, that was !"

[Tickman]

Fantastic levels of work there.

This is the sort of work I see in my future, finding faults like this. However I know nothing of how to test electronics so I will not even start stuff like this.

[Rust Collector]

4 hours ago, Sigmund Fraud said:

If AS ever publishes a workshop manual, I reckon it should have G&T ratings instead of the quaint Haynes spanner ratings.

"Yeah, that was a proper five G&T job, that was !"

The XM manual should come with a warning that ownership may cause liver damage 😂

4 hours ago, Split_Pin said:

Absolute Biblical levels of patience there. I'm like this:

..when it comes to wiring and electrics.

Very impressive man.

 

4 hours ago, Tickman said:

Fantastic levels of work there.

This is the sort of work I see in my future, finding faults like this. However I know nothing of how to test electronics so I will not even start stuff like this.

Thanks chaps - I’m sure someone who knew their way around car electrics properly would’ve sorted this in no time compared to my backwards and forwards method of trouble shooting though 😅

I was really lucky that the circuit diagrams are readily available for this car, so I could take my time and poke around with a multimeter and power probe - if I had of been going in blind then I think I’d still be chasing my own tail at this point.

I also can’t afford to pay someone to do this work, so there’s no other choice but to get stuck in 🤣

[Rust Collector]

There’s been some silence on this thread, as mother-in-law descended upon the house and so I have been otherwise engaged. Luckily I have recently been able to put her on a plane and return her to whence she came, so I’m now left with only one old lady who insists on spoiling any attempt at achieving joy: the XM, of course.

As ever, only the finest restoration techniques have been employed, to ensure a perfect* finish:

I forgot to take a photo, but I wrapped all the loom I removed from the wings and subframe whilst earlier tracing it for a break… that sucked.

The rubber in my crank pulley looked a bit sad:

The one on the spare engine had no cracking, so I fitted that one. I hope I don’t find a reason to regret that 😅 I swapped the lower timing covers too, as the spare one was free from cracks whereas the one on the car originally was battered.

It turned out the spare radiator I have is for a BX, which is a shame as the XM radiator is really tired.

The fins are badly corroded. If the car passes its next MOT, I might treat it to a new radiator as a bit of preventative maintenance.

The intercooler isn’t too happy either, it’s definitely leaking on both sides.

The tabs that seal the end caps on are rusting away. Again, if it proves worthy of it then it may find itself getting another intercooler, if I can find one.

Ive started throwing the 50 million cooling hoses back on. The ones at the back of the block were the worst, I did those first and I have a few of the easier ones left to do. This tool is a god-send:

I should’ve got one sooner.

Last but not least, I chucked the upper covers and the engine mount back on.

I had a bit of apprehension about this, as I think @wesacosa you may have had some trouble with this on your one? Luckily this one went on fairly happily - it took a little bit of lifting/lowering the jack to get it in, then the last bit of fine* adjustment was had by just grabbing the block with both hands and giving it a shake.

I’ve ordered more coolant, as I should’ve read the fucking manual and realised it takes quite a lot. Hopefully I’ll get it back together tomorrow, and then if I can sort the problems with getting it to start then I’ll have a half-ok car. Probably.

[wesacosa]

9 minutes ago, Rust Collector said:

There’s been some silence on this thread, as mother-in-law descended upon the house and so I have been otherwise engaged. Luckily I have recently been able to put her on a plane and return her to whence she came, so I’m now left with only one old lady who insists on spoiling any attempt at achieving joy: the XM, of course.

As ever, only the finest restoration techniques have been employed, to ensure a perfect* finish:

I forgot to take a photo, but I wrapped all the loom I removed from the wings and subframe whilst earlier tracing it for a break… that sucked.

The rubber in my crank pulley looked a bit sad:

The one on the spare engine had no cracking, so I fitted that one. I hope I don’t find a reason to regret that 😅 I swapped the lower timing covers too, as the spare one was free from cracks whereas the one on the car originally was battered.

It turned out the spare radiator I have is for a BX, which is a shame as the XM radiator is really tired.

The fins are badly corroded. If the car passes its next MOT, I might treat it to a new radiator as a bit of preventative maintenance.

The intercooler isn’t too happy either, it’s definitely leaking on both sides.

The tabs that seal the end caps on are rusting away. Again, if it proves worthy of it then it may find itself getting another intercooler, if I can find one.

Ive started throwing the 50 million cooling hoses back on. The ones at the back of the block were the worst, I did those first and I have a few of the easier ones left to do. This tool is a god-send:

I should’ve got one sooner.

Last but not least, I chucked the upper covers and the engine mount back on.

I had a bit of apprehension about this, as I think @wesacosa you may have had some trouble with this on your one? Luckily this one went on fairly happily - it took a little bit of lifting/lowering the jack to get it in, then the last bit of fine* adjustment was had by just grabbing the block with both hands and giving it a shake.

I’ve ordered more coolant, as I should’ve read the fucking manual and realised it takes quite a lot. Hopefully I’ll get it back together tomorrow, and then if I can sort the problems with getting it to start then I’ll have a half-ok car. Probably.

Good work. I had a fair old wrestle getting mine back on but it was disconnected for quite a while so suspect maybe it had sank on the other mounts a bit more. Was ok once I got a helper to manoeuvre it whilst I lifted it

Don't forget to fill and bleed the coolant with an extra header made from a coke bottle and don't let it get warm/soft and tip over like mine!

[Rust Collector]

10 hours ago, wesacosa said:

Don't forget to fill and bleed the coolant with an extra header made from a coke bottle and don't let it get warm/soft and tip over like mine!

I had a dream that I needed to use the car, and so bled it by just driving it with the cap off and pouring more in each time I stopped. This of course ended in disaster, and it was a relief to wake up and realise I hadn’t done anything that stupid. Yet.

I have some parts of my lisle funnel filler thing which I’m hoping I can cobble together into something useable. Sadly my son smashed the funnel!

[wesacosa]

11 minutes ago, Rust Collector said:

I had a dream that I needed to use the car, and so bled it by just driving it with the cap off and pouring more in each time I stopped. This of course ended in disaster, and it was a relief to wake up and realise I hadn’t done anything that stupid. Yet.

I have some parts of my lisle funnel filler thing which I’m hoping I can cobble together into something useable. Sadly my son smashed the funnel!

this was my attempt, pre disaster 

 

[Rust Collector]

Time for some good news then.

The work on the XM has been completed.

I still need to fit some bits of trim back on, and refit the interior. But it is now a working, driving car. It starts ok-ish now. I reckon with a bit more fiddling I can get it spot on. I will buy the proper* kit for timing the pump at some point as well. For now though I’m calling it good enough.

First job of the day was tightening the crank pulley. Being an auto, and not wanting to take the starter off for the millionth time, I got creative in order to get the last 60 degrees needed.

Surprisingly, that bar didn’t fuck off straight through the radiator. Happy days.

Next up it was time to fill it with margaritas.

 

That cobbled together header worked fairly well, it leaked a small dribble constantly but nothing to cause me any grief. I did have a panic when water started pissing out behind the engine, but luckily it turns out I’m a fucking idiot and forgot I opened the bleeders.

The fans came on, the system self bled, and incredibly the socket I forgot to remove from the crash bar did not fall into the fans.

To sort out the starting issues I re-checked my work. Mainly this thing:

The controls the fuel curve on boost, but also has an effect on idle. It’s eccentric, and if you don’t pay attention then there is a 1 in 4 chance of getting the side that drastically cuts the fuelling. I did pay attention this time, and I still fucking put it in that way round. I turned it to the side which gives the most fuel, and advanced the pump a bit. She now fires after turning over 4 or 5 times and gives a puff of smoke. Meh.

So there we have it - engine bay back together.

To celebrate this, I tore down a corner of the roof liner.

Bollocks.

A quick test drive was all I managed tonight, but all seems well. I notice that the inability to rev past about 3,750rpm has gone - I’m not sure what the rev limit should be on these, but that always felt low. I’m assuming I’ve set the governor slightly differently, so will have to take it out another evening and check that it can’t run away on me.

At any rate, I now have a dashboard clear of warning lamps.

Just whatever you do, don’t look over at the passenger side.

[High Jetter]

Persistence. Well done M9

[Rust Collector]

I put the dashboard together last night, and took the XM for a test drive. All good, bar a possible need to check, clean and gap the ABS sensors.

Today is my office day, so I jumped in the XM and started my commute.

Fuck sake.

The brake line for the OSF brake has blown. It was not looking great, and it runs near the ABS loom under the radiator, so my work must have disturbed it and ended its life.

It obviously needed doing, but it’s yet more work.

[Stinkwheel]

Every time I open this thread I think 'It must be nearly back to being a great car by now with all the work @Rust Collector has been putting in'

Then i realise its still being a complete swine. Then I cringe a bit and feel bad.

One day it WILL be a joy to operate, I'm just sad it isnt today

[Rust Collector]

20 minutes ago, Stinkwheel said:

Every time I open this thread I think 'It must be nearly back to being a great car by now with all the work @Rust Collector has been putting in'

Then i realise its still being a complete swine. Then I cringe a bit and feel bad.

One day it WILL be a joy to operate, I'm just sad it isnt today

Thanks mate, don’t feel bad though - it’s been my decision to keep pushing on. I agree with you, it will be a good car at some point, and I don’t think it’s very far off.

However, I have decided that this is now probably a good time for me to draw a line under it. I’ll fix the brake line, and then it needs to go to someone else - I think it deserves an owner who keeps it as a fairly dedicated project so that it gets the focus it needs, and I need a car that lets me focus on my many other projects.

I’m glad it got back on the road and I’ve enjoyed it when I have been driving it.

[Dyslexic Viking]

I'm starting to realize that owning a hydraulic Citroen is like putting ones dick on the kitchen table every morning and hitting it repeatedly with a hammer.

But well done for holding out this long and thanks for scaring me off from ever owning one.

[dozeydustman]

On 17/05/2025 at 22:05, Rust Collector said:

There’s been some silence on this thread, as mother-in-law descended upon the house and so I have been otherwise engaged. Luckily I have recently been able to put her on a plane and return her to whence she came, so I’m now left with only one old lady who insists on spoiling any attempt at achieving joy

This has to be in the Quote of the year 2025 thread.

[rob88h]

Dictionary

Definitions from Oxford Languages · Learn more

noun

noun: underdog; plural noun: underdogs

1. a Citroen XM thought to have little chance of working for more than one day.

   "we go into this commute with the underdog"
   
    

[Split_Pin]

I agree with your decision, except I'd stupidly and blindly keep the car in the hope that 'this is now it' and believe it's  going to be reliable from now on 😂

It hasn't put me off owning one but if I ever do, it will be a 100% hobby car that can be parked up until later if I get frustrated.

[Rust Collector]

42 minutes ago, Split_Pin said:

I agree with your decision, except I'd stupidly and blindly keep the car in the hope that 'this is now it' and believe it's  going to be reliable from now on 😂

It hasn't put me off owning one but if I ever do, it will be a 100% hobby car that can be parked up until later if I get frustrated.

This pretty much it - The car which I daily can’t be a hobby car at the moment, as it’s stopping me getting on with the other hobby cars.

I’m just aiming to free up my time a bit to focus on other cars, and some money back in will help with sorting the other projects.

Normally I would keep a car around until later, but the space and money would be helpful at present.

[Rust Collector]

The amount of parts that the brake line came out in can only be an indicator of how easy* routing the new line will be.

[Rust Collector]

I just stopped for dinner, followed by a yoghurt.

Does anyone know if the inside of yoghurt lids work the same way as tea leaves?

[Rust Collector]

I’ve made and fitted the new line. I won’t be winning any awards for aesthetics, but I was able to use the clips that aren’t broken and mostly follow the factory routing.

I had to lose a little bit of length at the end (I made a straight length up to 2.4m as per the parts catalogue dimensions, and bent it in situ. I’ll check everything clears before reassembly.

Josh, did you lose the key to the car during the 15 minutes that you came inside to have dinner?

Yes. Yes I did.

[Rust Collector]

Mwap mwap mwaaaaa

[Rust Collector]

If this doesn’t work then I’m not sure where to go with it next as I can’t be fucked to find and wait for a calliper and I need it off the drive.