Hi All
My K100 is getting a bit long in the tooth and has at this stage a starting problem,I bought it as is, knowing it needed attention and all things being equal I do intend to ride this machine,even at my age. :farao:

I have a reasonable mechanical and electrical knowledge having swung spanners most of my life but need help with this one.

Main faults is over fueling .On start up with throttle wide open engine fires up with copious amounts of black smoke whilst running,close throttle and engine dies immediately,wide open throttle is the only way I can get the engine to start at all.

I have checked the fuel pressure with a dead end guage and record a value of 65 psi, recconect the rail, injectors and pressure relief valve ,pressure is fairly steady at 33psi,seems to be within specs?
Applied 65 psi to the rail with injectors removed from the head and all seems OK with no sign of adverse leakage from any injector
Reconnected everything and went thru start up,it was very obvious that as the fuel pressure was coming up (say about2 seconds) all injectors sent out a steady stream of fuel,approx a teaspoon full from each injector,this flow continued up until the time of the pressure relief valve opening at approx 33psi, flow from injectors now becomes a mist or what you would anticipate to be normal but by this time engine is full of fuel and because of the black smoke I think the amount of fuel being injected is still excessive.I have tried another injector control unit of unknown values but the same result.
By disconnecting the fuel pump and gravity feeding the injector rail, motor starts on first touch of the button and idles away perfectly until gravity feed is exhausted

Many thanks in advance

BA99

Seems to me that you may have an unwanted earth.
The injectors have +12v to them all the time and the ECU puts earth to them for them to fire. The wire is a yellow with a gray tracer. Disconnect the ECU and see if there is an earth on that yel/gr wire (terminal 12 on the multi pin connector). If not test with the ECU connected. That is about the only thing I can think of at the moment that would hold the injectors open.

i think we have seen this many times before

in fact there have been quite a few posts with a similar issue described over the last couple of days .

try looking at this part of a thread https://www.k100-forum.com/t4662p50-hi-all-just-bought-a-non-running-k100rt#56940

the "temp sensor" (behind the radiator on the water stub ) which feeds the under seat injection control computer ...may well be connected but corroded

perhaps a removal and clean up could help establish a good start and idle

just a thought .

In the presence of giants. That's forum gold, you guys rock.
Possibly posted under the wrong category, gold none-the-less.

Even if the TPS fails, it fails full rich, which means start up ought to be normal but warm running will be too rich.

From your description it seems the fuel pressure regulator is taking it's sweet time to work. I would check for vacuum leaks everywhere, and I would check the condition of the vacuum hose that runs from the rear-most throttle body around the back of the engine to the fuel pressure regulator. When I had my rich running problem it was due to an old fuel pressure regulator. A very experienced tech and I chased our tails for many weeks on this before deciding to replace the regulator, but keep in mind that vacuum hose has to be free of leaks for the regulator to operate correctly.

The continuous spray from the injectors is the vital clue and as Rick says it seems as if you have an unwanted earth. Do the check he suggested, the injectors have a common permanent supply when running and a common pulsing earth when running. If the earth supply goes on solid the injectors will continue to inject fuel, no amount of air leaks or faulty signals from temperature sensors will give a solid earth. I hope it is a stray earth and not a failed control module. There are excellent circuit diagrams in this site which will help. I know Crazy Frog our esteemed leader had continuous fuelling because
the multi-pin connector was not clicked home once it was disconnected
and re-seated with the firm click from the latch all was well. Once you have sorted the continuous injection fault then it is well worth checking for air leaks and sensor connection problems to refine the running.
Regards,
K-BIKE

I will follow along on the suggestion of a stray earth,haven't been able to get into the shed for a few days as family functions have been more important

Regards

BA99

We all know what you mean, because when SWMBO (She Who Must Be Obeyed), says we must take care of family things, the only safe answer other than "Yes dear" is "Great Idea!
Regards,
K-BIKE