BMW K bikes (Bricks)

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1Back to top Go down   electrical gremlin Empty electrical gremlin Sat Apr 27, 2019 9:55 pm


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Hi all, this is a long back story, I hope that you are all fit, well, and rested for the marathon ahead. It is a long, complex story involving a recently purchased, running 84 rt two years ago, and now not running after I dropped it in my driveway (the bike fell out of the rubber handle, sending me over the top, and punching a hole through the fairing).
A new chapter in the bikes life was beginning.

After the removal of the fairing I was dismayed to find the bike utterly filthy and proceeded to make it spotless. In doing so I discovered that it needed at least two radiator hoses replaced, I had already found that it's speedo was not working properly when I was riding it, and it's rear brake switch needed replacing as well.

Everybody was speaking about deoxit for electrical stuff, so I bought some and hopefully fixed the speedo (will not know until it is going again), and replaced the brake switch.
The process of cleaning led to removing all of the air cleaning box, the throttle bodies, radiator, and ecu.

All electrical connections were put back together with deoxit being applied first. I also replaced the fuel pump, fuel pressure regulator, all the filters, air, oil, and fuel, external fuel lines, spark plugs, the little crooked breather pipe, and clutch and throttle cables, as well as taking the injectors to an auto electricians to be cleaned.

All of the above did not happen over night, but over a period of a couple of years. 
I started it on the first go when it was finally back together, however, it only ran for a few minutes, spewing out whitish grey smoke, and dribbling fuel on my foot from the junction in the exhaust system.
I have not been able to get it to fire again.

I pulled the injector rail with injectors attached and turned it over to see what was happening and was rewarded with a sideways fountain squirting out four streams of fuel, not a mist or a spray, but solid streams of fuel with no pulse, I had the plugs out and dangling at the same time and noticed that the spark was exceedingly weak, barely visible

While going over this tremendous site, I was constantly referred to crazy frogs excellent ecu resource, which all seems very straight forward, and probably is if one knew how to work a multimeter, (which I have purchased by the way).
My problem lies in the fact that of all the tests I have attempted, I believe that I have only done one correctly, and that is the fuel injectors, they measured at 16.5. 

I called an auto electrician and he quickly diagnosed that the ecu was at fault (it did appear that this was the culprit as there was an ant nest almost all the way across the top of the circuit board. How did they get into a sealed unit?) I replaced the ecu but still no go.
Can someone please step me through the procedure to test the icu, fuel relay and whatever else may be needed.

I am still sus on the injectors as there is a side story to them as well.
When I took the injectors to the auto electrician that advertised his ability to clean them, I was not aware that he was also in the process of selling his business. My son went and picked the injectors up for me after about two weeks. 
As I was replacing them into the head, I noticed that one of the injectors was missing a filter on the end so I returned it to the shop to have it dealt with, only to find that the person I was dealing with was no longer the owner. The new guy put the end on the injector with no qualms, but I do wonder if the previous owner actually did anything with the injectors, or just took my money.

I am looking forward to going for a ride with my wife one of these days, can anyone help me with a very detailed explanation of what to test and how to test it.
Looking forward to your replies with bated breath. 
Also, is this in the right area?
Partybus  electrical gremlin 259495


2Back to top Go down   electrical gremlin Empty Re: electrical gremlin Mon Apr 29, 2019 3:30 pm


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Did you check temperature sensor under the radiator. Clean that connector and try to start. When i had problem with that sensor I had to buy new one.


3Back to top Go down   electrical gremlin Empty Re: electrical gremlin Mon Apr 29, 2019 5:54 pm


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I have had my injectors cleaned twice professionally with no change to the slight problem I was chasing. I ended up doing it myself with a homemade air powered rig and it solved my problem. With fuel dripping out of your exhaust, check the vacuum line from the throttle body to the FPR for fuel. As well as the temperature sensor also check and clean the connector. Check your spark plug condition. Don't check your injectors on the bike without disabling the spark possible big BADDA BOOM.
Regards Martin.

K75s Hybrid

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