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Up Topic C1 Information / Repairs - Faults & Fixes / Wiring schematics anybody? - suspect faulty ECU
- - By Rich Date 20.10.18 16:57
Hi. Does anybody have the full set of wiring diagrams? The file at the download link on this site is incomplete.

I suffered a breakdown of my Williams 200 yesterday. Sudden loss of power at low speed. Engine stopped and would not restart. Starter motor was turning over fine, but after leaving it with ignition off for 5 mins and then trying again, starter motor no longer turning. Abandoned it and went back today with tools to take a closer look. Engine not seized. Ignition lights on and fuel pump running when ignition turned on. Battery fine. Temp and oil lights dim slightly when pressing starter button, but no audible click. Starter motor turns fine if I shunt the starter solenoid (but engine doesn't start). Checked voltage to control input of solenoid and only at about 0.5V when pressing starter button. Guessing it should be 12V. Checked all fuses. Bike originally had immobiliser/alarm but was disconnected years ago, and ignition lights are on so I don't think it's the immobiliser.

Hard to say without any wiring diagram to refer to, but wondering whether ignition (coil) power and input to starter solenoid are controlled by the ECU, and ECU has failed. Otherwise strange co-incidence that loss of power and then starter problem happened simultaneously

Tried re-seating connector to ECU and re-seating all relays, but no luck.

Only idea I have now is to source a replacement ECU and try swapping it out. Anybody got any other ideas?

My C1 has ABS. Does anybody know whether the replacement ECU needs to be from a donor with ABS? (I'm presuming it has to be from a 200 and not a 125)
Parent - - By rockstedy Date 20.10.18 19:25
Parent - By aware Date 20.10.18 20:20 Edited 20.10.18 20:25
Can it be the starter relay? I think this under the right side rear panel.
Engine should start with 12v on starter motor however. Did you try with strong battery and good quality cables?
Parent - By leonm Date 21.10.18 05:37
set of drawings
Attachment: Circuit2.pdf (188k)
Attachment: Circuit1.pdf (191k)
Attachment: Circuit3.pdf (177k)
Attachment: Circuit4.pdf (262k)
Attachment: Circuit5.pdf (195k)
Attachment: Circuit6.pdf (304k)
Attachment: Circuit7.pdf (260k)
Attachment: Circuit8.pdf (175k)
Attachment: Circuit9.pdf (132k)
Parent - - By leonm Date 21.10.18 06:06
1. check brown wires bolted to lug of starter motor for tightness. accessible without removing any fixed panels
2. check battery terminals for tightness
3. could be a failed battery. connect voltmeter to battery terminals direct on battery. switch on, read voltage. should be over 12v on DC scale.  switch headlight on, voltage should not be less than about 11.5V. 
4. another possibility is a failed charging circuit, to be tested once you have the engine running
Parent - - By Rich Date 21.10.18 08:05
Hi leonm,

Many thanks for posting those schematics. Much appreciated. I will take a look. Battery, cables and connections are all fine, as I can get starter motor to spin by shorting out the output connections on the starter solenoid (relay) behind the RHS rear panel. It seems that it is the control signal into that relay which is at fault - it only reads at 0.5V when I press the starter button, so need to trace back wherever that is coming from. Hopefully your schematics will help! Found a 200cc ECU on Ebay for £40 so have bought it -  if it turns out mine is not faulty at least I will have a spare.

Spent some time last night researching and considering what to do if I had to replace C1 with something else. There is literally NOTHING else out there that meets my purposes. BMW C1-E would have been ideal, or Peugeot Hymotion. But none of these vehicles seem to get beyond prototype stage. Can't understand why the whole commuting world doesn't want a safe, economical weather proof vehicle that can slip though traffic effortlessly.
Parent - By alunt Date 21.10.18 09:27
Fully agree with your last sentence, but it seems we are in a minority, people would rather sit in traffic jams in their cars!
The way you describe the break down and then inability to start the engine does sound like charging fault leading to a weak battery. Just to be certain I would try jump starting your bike and see what happens. The engine will turn over on a weak battery but won’t start, this could be your problem. It’s quite rare that people report faulty ECUs on here - probably why they’re easy to find on eBay.
Parent - - By leonm Date 21.10.18 09:50
check emergency stop switch. will give symptoms described
Parent - - By Rich Date 24.10.18 07:46
I had the bike towed back and have made some progress. No closer to understanding why the loss of power in the first place, but have established that the starter solenoid has failed. Probably burnt out through repeated efforts to re-start the engine.. Starter motor has been sounding weird for a while, and struggles to turn over effectively with a fresh battery. So likely it was drawing too much current and needs sorting too. Has anybody had any success with these cheap pattern starter motors that are being offered through ebay?

Once I've sorted starter out I can get on to solving the original problem!
Parent - - By HelmetHair Date 24.10.18 09:51
Start with the basics. Check all is secure, especially earths as per Leon, then check you have fuel, a spark, and no air leaks. Regardless of what the problem is, a new starter and solenoid will not do any harm-and if the starter was already giving up the ghost then its a good idea to eliminate that issue.

Then move on to compression.

My money is on a simple fuel or spark problem, and it might be as simple as the connection to the fuel injector having broken wires-this would still enable the starter to turn and the fuel pump to buzz, and also matches the way the engine stopped while driving.
Parent - - By aware Date 24.10.18 14:43
It helps a lot if you make a video of how the starter behaves and share with us.
Parent - By p.gill Date 24.10.18 15:04
One thing to be aware of, some pattern starters have only two brushes instead of four, it wouldn’t turn the engine over, had to refurbish my old motor. 
I do not know if all pattern starter motors have two brushes, you cannot tell by looking at the motor, only by parting can you be sure.
Parent - - By leonm Date 24.10.18 16:49
starter motors can be quite troublesome when they get old
       the usual problem is that the four brushes  get worn away to the point where they stop making contact and need replacement. they are rather tricky to replace (brushes obtainable from forum member variobob).  i seem to recall that he also has starters on an exchange basis (strongly recommended option).
       a second possibility is that the oil seal on the starter motor shaft has failed and the starter is filled with oil, which will of course impede proper working. tricky to open and re-assemble starter.
  i recall that some forum members have reported on ebay clones.
Parent - - By Rich Date 17.11.18 23:51
I've made some progress. Starter relay had burned out, now replaced. Starter motor was not working very well, probably putting too much load on relay. Tried replacing with a cheap pattern part which was rubbish so cleaned mine out (had some oil in it, but brushes OK). Now good. Sprag clutch had been making horrible noises for a while and was very worn so renewed that too. So starter system now good and I'm back at the original fault which caused the engine to die and fail to restart. Seems I have no spark! Fuses/relays all good, ignition lights working. Fuel pump whirring, starter turning on the button.  Spark plug, HT lead and coil all changed. Still no spark. I'm thinking ignition sensor next? Does anybody know how to test this, and how I source the cheaper generic version of the part rather than paying the outrageous £140 BMW want? Or am I barking up the wrong tree? This has all turned into quite a saga...
Parent - By aware Date 18.11.18 06:43
Please refer to a recent post by leonm with expected readings when measuring the crank sensor resistance.
Parent - By HelmetHair Date 18.11.18 09:24 Edited 19.11.18 11:52
I'd look into the old immobiliser and make sure it was removed properly and that any connections are good
If, for example, wires have been cut and twisted together this bad connection can cause problems.
Otherwise checking the crank sensor and it's wiring is a good idea.

Regardless, it sounds like the work you've done needed doing anyway, so not time wasted!
Parent - - By leonm Date 18.11.18 09:29
the starter motor is fitted with an o ring to prevent oil from the engine entering the starter. just in case you missed it.
the identical or similar sensor is used on most bikes to my knowledge. should cost you no more than £15. transfer cable to new item, soldering required
i recently posted some ideas on testing the 2 wire link between the sensor and the ecu. wiring failure from the sensor via the rubber grommet to the flying plug near the starter relay is a known failure area
Parent - - By Rich Date 18.11.18 10:15
Thanks everybody for good advice. I had wondered about immobiliser. It's a while since I disconnected it - I remember that I had to move some connectors around behind the dashboard to bypass it. Wiring schematics I have do not show any of the immobiliser wiring, so I'm not completely certain it's not the issue. Today I have ascertained that the TDC sensor is OK (200 Ohm resistance), and that the wiring between it and the ECU is sound (continuity tested). The wiring between ECU and coil is also sound, and coil is getting power from ECU OK. However, it doesn't seem to be getting the firing pulse when cranking (using multimeter in AC mode to check input to coil). So for some reason ECU is not sending the spark pulses to coil. Suppose ECU may have a fault but seems unlikely? I actually bought a spare and tried that, but I think that one really is bust as it doesn't illuminate the temperature warning lamp when ignition is switched on. Alternator cover and exhaust are off right now, so lambda sensor and alternator are disconnected but I don't think they would cause ECU not to send spark signal?  Am now going to have a break and re-charge battery just in case diminishing battery voltage is clouding the issue. Maybe it's time to borrow the C'mon...
Parent - - By aware Date 18.11.18 10:47
How did you test whether or not you have spark?
Parent - - By Rich Date 18.11.18 11:16
Spark plug out, body of plug earthed to chassis.
Parent - - By aware Date 18.11.18 16:10
You seem competent enough so all things lead to 2 main possibilities:
1. Immobiliser having to do (there should be some instructions on how to disable it for good on forum)
2. Faulty ECU.
can you swap with another C1 bike? It's easy since you take yours and simply plug it on the plug of the other. No earthing required etc, just plug n play.
otherwise there is some instance of burnt part in ECU (i think on german forum) where the problem could be seen on the circuit, as such why not open the ECU case and have look

By the way, please check also relays above fuses
Parent - - By Rich Date 18.11.18 16:49
Yeh. I'm coming to the conclusion that it's the ECU too. I've traced back all the wiring from ECU connector to all sensors and actuators, and it's all good - well it is now. I found out that I had a broken wire just above the injector and thought I'd solved it, assuming that the ECU had detected the open circuit and was not firing the plug. But alas, no. Fixed that and still no spark (though now a smell of petrol).  That wire maybe cracked off when I lowered the engine to get at the starter motor. Irritatingly the spare ECU I bought from ebay is completely dead. I think I'm down to two possibilities now - either an ECU fault, or both my coil and the s/h replacement I bought from ebay are both faulty. Grrrrr. Good idea about cracking the ECU open. I had the ebay one open and can see the transistor that drives the coil.

Very confident it's not the immobiliser now. All pins on the ECU are accounted with power where it should be.

Do you have the URL for the German forum by any chance?
Parent - - By leonm Date 18.11.18 21:00
before going the ecu route, have a good look at the motronic relay circuit and  just give these items a last check.
  with ignition switched on, you should measure 12V between ground (chassis) and 1) coil 2) fuel injector 3) diagnostic plug  4)  fuel pump should momentarily run
  if not, check kill switch circuit
Parent - By aware Date 19.11.18 08:03
The old German forum was phased out due to GDPR rules.
It used to be
Up Topic C1 Information / Repairs - Faults & Fixes / Wiring schematics anybody? - suspect faulty ECU

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