Hi guys

Still on the trail of intermittent cut-out at high temperatures.

I must still do a proper test on the Hall sensors, but could not replicate the cut-out problem using a hairdryer - will warm them properly over the weekend when I get hold of a heat gun .

However, I think the relays are overheating. In my previous posts I mentioned that I was reading temperatures of around 50 deg C, and in the last instance, when I experienced the last cut-out, it went up to 62 deg C.

I have now fitted a 60 mm x 60 mm 12 V panel fan to the rear of the relay box, inside, under the start relay. The idea is to draw fresh air from under the seat (hopefully it will stay fresh ) providing forced ventilation to the relay box (the cover does not fit tightly, so the air will be pushed out there).

I now have to provide power to the fan, and want to connect it to the main cooling fan circuit (no use in having my relay box cooling fan running unneccesarily) - I am also considering a "tell-tale" light on the dash (I saw a similar post here somewhere on that as well).
I want to take 12 V from the switched side of the main cooling fan (so that when it switches on, my relay box fan also gets power), via a small fuse for protection, which I will add to the existing fuse rail.

Now - I have seen posts on this forum showing the fan motor is switched via the "Temperature Sensing Switch Unit", which is also as shown on the Interactive wiring diagram. This is also as per the wiring diagram in my Haynes service manual. According to all these diagrams, I will get my 12 V from pin A2 on the relay.

HOWEVER, my wiring is different (K100 RS 4-valve 1990), and the closest description I could find of my particular relay box layout was on the Motobrick forum:
" />

Below is a picture of my actual box:
" />

Relay ID's (according to Motobrick's pic):
1: Motronic (? - not sure what this is)
2: Fan
3: Horn
4: Fuel pump
5: Load shed
6: ABS (? - my bike is not equipped with ABS)
7: Bulb monitor (confirmed as such on thread with Ned's post)
8: Flasher relay (? - According to Ned's thread, this is the Temp Sens Sw Unit?)
9: Starter relay

Can anyone shed some light here please - where do I find the +12 V supplied to the main cooling fan?

Hi Big G
Firstly, you've posted about this issue before I think, so its important that you keep all your posts regarding the same issue in the one thread. That way everyone can see what's been discussed and what's dealt with or not dealt with. Otherwise it becomes very difficult over a forum like this.

However, from the pic of your relay box you don't appear to have a temperature control unit which should be on the middle/right. You can see ther is a vacant fixing lug there. EDIT: This could be particular to 16v electrics tho.

If you post your VIN it will be easier to find the correct parts diagrams.

Have you read the information in the links off the Portal tab. Everything is explaned in there especially this...
EFI/Electronic ignition troubleshooting

Cheers mate

Text has been deleted because it was not being read

Can we get a moderator to combine this with the previous thread please.

Kaptain Holister wrote:Hi Big G
Firstly, you've posted about this issue before I think, so its important that you keep all your posts regarding the same issue in the one thread. That way everyone can see what's been discussed and what's dealt with or not dealt with. Otherwise it becomes very difficult over a forum like this.

However, from the pic of your relay box you don't appear to have a temperature control unit which should be on the middle/right. You can see ther is a vacant fixing lug there. EDIT: This could be particular to 16v electrics tho.

If you post your VIN it will be easier to find the correct parts diagrams.

Have you read the information in the links off the Portal tab. Everything is explaned in there especially this...
EFI/Electronic ignition troubleshooting

Cheers mate

Hi Kaptain

My other post and resulting thread referred to the cutting-out issue.
Now, I have hopefully identified the problem and am trying to ID the relays so that I can implement the solution.

I have researched the troubleshooting extensively, both on this forum and others, especially the Electronics section. The flowchart in the link you referred to, eventually pointed me to "Bad Relay".
Unfortunately, this happens so intermittently (this week the first time in about 6 months), and always on the road, far away from tools and test equipment. By the time I have got the bike back at my workshop, the problem has disappeared again!

Missing Relay:
If the Temperature Control Unit is supposed to be installed, would the bike still run without it?
There seems to have been some aftermarket modifications to this bike - the ECU also seems not to fit all the fixings properly?
I will this weekend open all the relays in the larger boxes and post pics of the innards, so that we can confirm the ID of each.

VIN No:
VIN: 6408293K100RBCJ
Engine: 104EB17902194

BimMerWork (http://bimmer.work/) returns the following:
" />

And Phil Hawksley's BM Bikes (http://bmbikes.co.uk/chassispages/enginechassisK100.htm) also gives it as a European production model 04/90.

It would be great to have the proper wiring diagram and relay layout.

Cheers,

You'll have to rely on others who have 16v/Motronic knowledge and experience but here's my 2 cents worth.

Big G wrote:I must still do a proper test on the Hall sensors, but could not replicate the cut-out problem using a hairdryer - will warm them properly over the weekend when I get hold of a heat gun

I'd be a little careful using a heat gun. they can get really hot and you risk damaging the insulation on the wiring. That's why the HES fail to work... the insulation on the leads breaks down due to high temps over a long period of time. A hair dryer should be enough. However, you say the pump stops working.... HES failure will not do this (as far as I know... someone correct me if that's wrong)

I'm beginning to think that the apparent overheating could be a Red Herring. I'm not saying your engine is not getting hot. Its a fact that it can get pretty warm under the tank. That's well documented here and on other sites. I think Rick G suggested that it could be a vapour lock due to the fuel overheating. The Johnny Blanket could be the solution.

There's a possibility that you have an air leak into the intake and/or crankcase which will lean your fuel mix making your engine run a little hotter than normal.
Check your crankcase breather hose, intake rubbers, vacuum caps, vacuum hose to the FPR and injector rubbers for leaks.

Hot engine aside, there will be a logical explanation as to why your engine cuts out randomly. I'd take a guess that its something electrical like a loose or broken connection (you mention rough roads in your previous thread).

First thing I would do is check and clean (DeoxIt) all connections paying special attention to earth connections. Frame under tank, gearbox battery earth and starter motor fixing point (2 bolts).
Make sure your battery is up to scratch and you're getting correct voltages from your alternator.
Check your starter motor brushes. They provide earthing thru the motor for other parts as well.
Check the temp sensor for correct ohms reading at ambient and running temperatures.

These things can be done very easily and if it doesn't fix the problem, it will at least provide a 'level ground' from which to trouble shoot other components.

Checking relays internally will reveal any electrical damage to contacts or cracking of solder joints (rough roads can do that).
Have you tried swapping out the fuel relay? or bench testing the unit? or testing for correct voltages on the relay socket?

Have you considered that it may be the ignition switch. Quite a few of us have had cutout problems with this as our bikes are getting 20+ years old. Remove, clean, regrease and replace will take less than an hour.

Just my thoughts
Cheers

+1 on the Kaptain's comments, especially with regard to electrical connections. 

I have had intermittent cutout on two of my bricks that was caused by a loose/dirty connector for the fuel tank shutting down the fuel pump in one case , and by a dirty ignition switch causing electrical system shutdown in another.

From the threads posted here and on other K-bike sites I think it is safe to say that these two components are responsible for a fairly large number of the intermittent shutdowns that aren't Hall sensor related.

I would get to them and the engine control unit connector with DeOxIt before pursuing any other troubleshooting avenues.