G'day

Hello and thanks for the encouragement Stewart.

I have been "experimenting" with reprogramming the BSI's EEPROM. Changing the VIN and engine ECU PIN code. No luck. The automatic climate control runs all the time and a few other bizarre things happened! LEXIA will not read the "new" VIN. When polled I get qqqqqqqqqqq. I can "tell" LEXIA the new VIN but it just cracks up and goes into a loop.
I suspect there are check sums hidden some where or individual BSI's look for information in slightly different spots on their EEPROM. So if you "move" EEPROMS around, the BSI's CPU goes looking in the "wrong" place on the EEPROM.
I was transferring the whole, but modified, EEPROM dump from one BSI to another BSI. I noticed in the hex of the EEPROM files that the VIN was placed in a slightly different place on each EEPROM. I probably should have just modified the original HEX for that particular BSI. Or just modified one bit of the original HEX file at a time. Or just transfered the whole, untouched, HEX file!
I might have tried more combinations but installing and removing the BSI is a pain in the ... I need to do a bit more experimenting.
The goal was to change the engine PIN code so that I could install a more modern engine ECU in the C3. I think I was over ambitious! I should have just changed one thing at a time and see what happens. I should have stuck to the plan and just changed the PIN code. It's also possible that you may not be able to just swap EEPROMs from one BSI to another! Still more work to do.
I wondered why people were changing the engine ECU PIN in the engine ECU and not in the BSI...I think I might know why now!
Oh by the way, I have a "sacrificial" C2 BSI and engine ECU that I am experimenting on. I can copy the EEPROMs from the silver and the black C3s BSIs onto it. But I'm not reprogramming the silver or black BSIs (and 'bricking' them) ... just yet.

Hmm C3 is still off the road. No problems, just taking my time.
Head gasket installed and tutorial done! Air con compressor, lines and condenser replaced.
I have to re-gass the air con system, install the passenger side headlamp and put the front bumper and grill on.

The "black" C3 had an after market radiator fan and speed controller combo. I thought I would install that and see how it went. FAIL! The fan stayed off until the engine came up to temp then it came on...full blast! Even when I shut down the engine and turned the ignition off...it kept running! Hmm will have to investigate that one when I get time (job#1634). Re-installed original fan and it ran fine.

This picture gave me the idea to build a fuel injector (petrol) test set.
See how it's slightly rich on 2 spark plugs and slightly lean on 2 spark plugs? It's possible all 4 injectors are not matched.
Now all things being equal these plugs look fine and show a healthy engine. So you usually wouldn't bother with all this guff. But apparently I have OCD! No offense meant to anyone with OCD!

The engine ECU uses the O2 sensor to tell if the engine is running rich or lean and modifies the injector timing accordingly. BUT the O2 sensor only sees the aggregate of all 4 cylinders. It cant differentiate between individual cylinders. So if one or more injectors are not putting out the same amount of fuel per stroke as the others, you will get miss-matched performance on the cylinders and an inefficient engine.Too much fuel (in any cylinder) or not enough fuel (in any cylinder) reduces over all engine power.
Now it's not as critical that they put out the correct amount of fuel as they all put out the same amount of fuel. The engine ECU can use the O2 sensor to correct the amount of fuel used. Yes, it will show up in the fuel trims but as long as the fuel trims stay under 5%, it's OK. 5% is about the most you should allow for "manufacturing" or engine wear tolerances.
So I guess I would be looking for a difference of not more than 5% of output between the injectors?

Here are the bits I have accumulated so far. 4 measuring cylinders, fuel tank, fuel pump, hose clamps, 'P' clamps for fuel pump, injector controller, 6-way electrical connector for the injector harness and fuel rail quick-connect.I just need a switch for the fuel pump, something to install it on and fuel hose. Oh and some electrical wire!
When I am finished the injectors and fuel rail will sit in the top of the measuring cylinders. The injector driver will be wired up to the OEM injector harness to drive all the injectors at once. The fuel tank will be hooked up to the fuel pump then the fuel pump is connected to the knee bone! Er..the the fuel rail, using the quick connect fitting. The 'P' clamps holds the fuel pump to...whatever I decide to mount this thing on!

Will it make a difference in the long run? Probably not, but I'm interested to find out.

When I pulled apart the COMM2000 (the switching stalks behind the steering wheel) I noticed that the PCB had an "edge connector" set of fingers. This usually means that something plugs into the edge of the PCB. I knew that the later COMs units had "pod" style cruise and radio controls. I also noticed that some of the up market Citroens and Peugeots (cars of that era) had these pod style of cruise controls, but they were VERY rare!! To make things clear, I am talking about the CAN-VAN cars built up 'till the middle of 2005. The COMs units look similar for pre and post 2005 but they are VERY different and are totally incompatible!
The pre 2005 cars (C2 and C3s) had the "flappy paddles" as modules that plugged into the side of the COMs unit and the cruise control buttons were mounted in the steering wheel. By the way the flappy paddles were purely mechanical and pressed onto switches soldered to the COM's PCB. They did not plug into these PCB edge connectors.
I noticed that the later pod controls had mounting "spigots" that looked very similar to the mounts of the flappy paddles. Turns out they are the same! The pods also had contact fingers that looked like they would make contact with the edge connectors of the PCB.
OK, so the question is; can I get the newer pod style cruise control to work with the older COM's units???
As I mentioned, the older cars, with cruise control, had a special steering wheel that the controls were part of. These steering wheels are getting harder and harder to find. At least in good condition. And you will NOT find them here in the antipodes!! The switching signals for the cruise control in the steering wheel, came through the "clock spring" wiring that also ran the airbag in the steering wheel.

The COM's units: Unless the car (that the COM's unit is coming from) had cruise control, the COM's units are not capable of cruise control!! The exception seems to be the the flappy paddle versions. As far as I can discern, ALL of the sensodrive COM's units are capable of cruise control, whether the car came with it or not.
So, if the COM's came out of a car with cruise control (not flappy paddles) that COM's can run cruise control (but probably only the steering wheel type). If the COM's came out of a car with flappy paddles, that COM's can run cruise control (steering wheel or pods). Otherwise...no cruise control.

To absolutely confuse everyone (well, the one person reading this), I put the "clock spring" from a steering wheel type cruise control COM's, onto a plain vanilla COM's unit...and the cruise control worked!!!
If you figured out why it works, write your answer on a Cornflakes box top and send it with a stamped, self-addressed envelope to PO BOX 12345 in your capital city!!

I shall get back to you and let you know how I get on.

Not that long ago, there were quite a number of these original cruise control steering wheels in a warehouse in Greece. Original parts, new old stock, in the original Citroen box. Good price too for something that would otherwise be impossible to find. It is always worth checking oneBay, you just never know what you will find

Yes I have seen those on Ebay. Good price, although the postage to AUS was prohibitive.
I have the steering wheel version but It needs a trip the upholsterers to get re-covered. It's seen better days.
Being the ever Nosy Parker, I just wonder about stuff and if those pods would work? It would be a cheaper and easier alternative than finding the correct steering wheel.
The C2's and C3's were NEVER offered with the extras like you got over there. I did add the GT grill, cruise control, CD stacker, power folding wing mirrors and headlight covers to the C2.
A bizarre story about the C2 headlight covers!!!! They were not available for sale here in Australia, only the UK (genuine Citroen accessory). I bought 2 sets from a seller in the UK and they shipped them here. Not very bizarre so far? When they arrived they came with fitting instructions from the actual manufacturer (not Citroen, hmmm). Well the manufacturer was EGR plastics...here in Brisbane!!!!!! So for me to obtain them, they had to literally go around the world!!
My C3 does have the all glass sun roof, but it's not working ATM. Things like cruise control, power fold mirrors, reversing sensors, SatNav, were never offered as optional extras, or stock on any model. The sun roof, climate control and alloy wheels where the only options. Oh, the later C3's with the sun roof got heated leather seats...but you lost the climate control. My C2. The dealership had the decals added as 'the C2' was entered in the JWRC competition at the time. It's still just stock. I have made comments about it earlier in this thread.

Well.. I removed the switches from the PCB.
The cruise control pod fits the PCB perfectly. So I installed it on the steering column... Plugged in LEXIA and tested the switches.
FAIL!! The switches do not change state on the LEXIA page.
I plugged in the steering wheel type switches into the electrical connector and they worked!

I could not find any way of changing the cruise control switch arrangement in LEXIA. I guess the PCB must be configured in some way. The PCB is from a car with flappy paddles, so the cruise control would normally be the the steering wheel type. They obviously run one or the other and not both at the same time.
I'll have a look and see what I can do, but I don't hold up much hope.
Oh well.

I am loving this thread so far. I have just got a 2021 Citroen C3 and have a 2002 Exclusive auto. Keep this thread going with loads of pictures please. Im loving this. Where in oz are you?

Thanks Daniel. I'm in Ipswich just outside Brisbane, Queensland. Change your gearbox oil!! LOL!

Itchy is back on the road. Yes, I know, I procrastinated a lot.

No loss of coolant, no oil leaks. Engine is a bit "tappety" a few seconds after start up but seems to disappear when warmed up. Still, I might check the valve clearances again just in case.

AL4 auto gearbox is "better" than it was. The occasional down-shift when coming off the highway onto the off ramp is a bit clunky. I changed the valves as I believed the performance could be better and blamed the gearbox faults on the valves. They turned out to be the old "white" style of valve. The last gearbox valves I did (on another C3) had failed completely and the gearbox went into limp mode. After fixing that, the gearbox took about 2 weeks to "settle down". This one has only been on the road for about a week. It is making small advances.

The engine performance is worse than I remember! I have mentioned the 1984 Ford (Mazda) that I own and "on paper" the carbureted 1.5 of the Ford produces the same power as the injected 1.4 in the C3...on paper! In reality the C3 is down a noticeable amount of power over the Ford. Indeed the "other" C3 I rescued had more power than this one and the Ford is not a spring chicken!
So my next job is to find out why the engine power is down. I am suspecting my "cheap Chinese" fuel injectors. That's why I'm building the injector tester. While I do have a set of genuine injectors out of the "black" C3, I want to do some comparisons and empirical testing.

Well I've managed to finish the injector tester!
Here is a photo of the guts. Nothing fancy, it's basically just a distribution box with a switch on the top. I used "banana" plugs as the output of the electronic controller so I can make up leads for different injector plugs.

...And here is the finished product. I have only just finished it and have not run it yet. Lets see if I have an even greater story about my failure?
If there is still anyone out there who is interested (or still awake), I'll give you a rundown on what its made of and how it works (if it works).