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K100-forum.com » Technical, repair and troubleshooting » K100 fuel injection

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1Back to top Go down   K100 fuel injection Empty K100 fuel injection Sat Nov 02, 2019 9:16 pm

K100TRIKE

K100TRIKE
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I have an early 1991 K100 LT which is being converted to a trike. Tried starting it today and discovered that when the ignition is turned on the injectors open and stay open. I assume this is a fault with the fuel injector control unit which I believe cannot be messed with to fix it. Damn nuisance cos it ran fine when I started the job(admittedly that was 4 years ago). Any ideas please.

    

2Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Sun Nov 03, 2019 4:41 am

K75cster

K75cster
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Hmmm, was the battery disconnected and the electronics before any welding took place?
You know how delicate they can be at times.

I'm expecting you welded a new tail section on to house the trike rear wheels.


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

3Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Sun Nov 03, 2019 6:41 am

Laitch

Laitch
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K100TRIKE wrote: Tried starting it today and discovered that when the ignition is turned on the injectors open and stay open.
Fuel is exiting the exhaust pipe during starting; the spark plugs are wet when examined?


__________________________________________________
1995 K75 90,000 miles
    

4Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Sun Nov 03, 2019 10:16 am

K100TRIKE

K100TRIKE
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K75cster wrote:Hmmm, was the battery disconnected and the electronics before any welding took place?
You know how delicate they can be at times.

I'm expecting you welded a new tail section on to house the trike rear wheels.

Everything was off cos the bits where they were was cut off to fit new rear end. The control unit has been stored in a box on a shelf until I needed it. Thanks for looking anyway.

    

5Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Sun Nov 03, 2019 10:20 am

K100TRIKE

K100TRIKE
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Laitch wrote:
K100TRIKE wrote: Tried starting it today and discovered that when the ignition is turned on the injectors open and stay open.
Fuel is exiting the exhaust pipe during starting; the spark plugs are wet when examined
Oh yes. Took the injector rail off with injectors attached. Connected fuel pump to battery and turned ignition on. Injectors fully open all the time.

    

6Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Sun Nov 03, 2019 6:16 pm

Point-Seven-five

Point-Seven-five
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The injectors are opened by GROUNDING them.

Check that there is no continuity to ground in the injector wiring harness with the FICU unplugged.  That will tell you if there is chafed insulation causing a short circuit to ground. 

If that is okay, the problem is a blown output transistor in the FICU.  I seem to recall that the transistor can be replaced and that there are instructions somewhere on the interweb.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

7Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Sun Nov 03, 2019 9:17 pm

K100TRIKE

K100TRIKE
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Point-Seven-five wrote:The injectors are opened by GROUNDING them.

Check that there is no continuity to ground in the injector wiring harness with the FICU unplugged.  That will tell you if there is chafed insulation causing a short circuit to ground. 

If that is okay, the problem is a blown output transistor in the FICU.  I seem to recall that the transistor can be replaced and that there are instructions somewhere on the interweb.

That's a useful bit of info. I will try that tomorrow and see what happens. Watch this space. K100 fuel injection 112350

    

8Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Fri Nov 08, 2019 9:06 pm

K100TRIKE

K100TRIKE
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K100TRIKE wrote:
Point-Seven-five wrote:The injectors are opened by GROUNDING them.

Check that there is no continuity to ground in the injector wiring harness with the FICU unplugged.  That will tell you if there is chafed insulation causing a short circuit to ground. 

If that is okay, the problem is a blown output transistor in the FICU.  I seem to recall that the transistor can be replaced and that there are instructions somewhere on the interweb.

That's a useful bit of info. I will try that tomorrow and see what happens. Watch this space. K100 fuel injection 112350

Right. Work this one out. FICU unplugged. ICU unplugged. Air flow metre unplugged. Still got continuity to earth from the green/red wire. Unplug the Hall sensor and we have open circuit. It seems to be the black wire that is the -ve on the Ignition Trigger Assemblies which goes to the Ignition Control Unit. Opened the Hall sensor up but all 'looks' to be ok but I have no idea how to test this apart from replacing it and that can get expensive.
Any ideas???????? K100 fuel injection 259495

    

9Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Fri Nov 08, 2019 9:51 pm

Laitch

Laitch
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K100TRIKE wrote: Opened the Hall sensor up but all 'looks' to be ok but I have no idea how to test this apart from replacing it and that can get expensive. Any ideas????????
There are tests for many systems including the Hall Sensors in this guide from the Tech pages on the site. Have a read through it. It could help clarify things.


__________________________________________________
1995 K75 90,000 miles
    

10Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Fri Nov 08, 2019 10:25 pm

K100TRIKE

K100TRIKE
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Laitch wrote:
K100TRIKE wrote: Opened the Hall sensor up but all 'looks' to be ok but I have no idea how to test this apart from replacing it and that can get expensive. Any ideas????????
There are tests for many systems including the Hall Sensors in this guide from the Tech pages on the site. Have a read through it. It could help clarify things.

Thanks for that Laitch. There is a lot to get through so I will read it when I have all day to try and adsorb some of it. Hope fully that will solve the problem. Damn nuisance cos it used to run ok.
Cheers
Ralph

    

11Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Mon Nov 11, 2019 9:53 am

K75cster

K75cster
Life time member
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I don't think the hall sensor is earthed, maybe check the wiring for abrasions and a short to earth that way. Perhaps if they are after market Hall sensors, they could be shielded wire harness and if that is earthed maybe there is a short in there some place.


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

12Back to top Go down   K100 fuel injection Empty Fuel Mon Nov 11, 2019 10:08 am

daveyson

daveyson
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You were checking the green/red wire,  but I think you should have been checking the yellow/grey wire.


__________________________________________________
11/1985 BMW K100RT (late model)  Vin. 0090567
 ~120,000 km
    

13Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Mon Nov 11, 2019 2:52 pm

K100TRIKE

K100TRIKE
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K75cster wrote:I don't think the hall sensor is earthed, maybe check the wiring for abrasions and a short to earth that way. Perhaps if they are after market Hall sensors, they could be shielded wire harness and if that is earthed maybe there is a short in there some place.

The originals are shielded as far as I can see.  There shouldn't be any abrasions on the wiring as it hasn't moved since it last ran but I am still going to check.

    

14Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Mon Nov 11, 2019 2:55 pm

K100TRIKE

K100TRIKE
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daveyson wrote:You were checking the green/red wire,  but I think you should have been checking the yellow/grey wire.

I did wonder about that as the green/red wire is the power supply, I think. Yellow/grey is fine. No continuity to earth. When I get chance I am going to check all the components as far as I can and all the wiring. I think it's going to be the only way. Wish me luck.

    

15Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Mon Nov 11, 2019 3:41 pm

Laitch

Laitch
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Good luck! cheers


__________________________________________________
1995 K75 90,000 miles
    

16Back to top Go down   K100 fuel injection Empty Fuel Mon Nov 11, 2019 7:38 pm

daveyson

daveyson
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Have you checked the temperature sensor, that often rescues bikes suffering from gross overfueling. For starters that the temperature sensor plug is clean and clean and clean and tight.


__________________________________________________
11/1985 BMW K100RT (late model)  Vin. 0090567
 ~120,000 km
    

17Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Tue Nov 12, 2019 9:50 am

K75cster

K75cster
Life time member
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The Red Green is a common to all injectors were they disconnected when testing. I cant see a link between the Hall sensors and the red green wire anyplace.


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

18Back to top Go down   K100 fuel injection Empty Re: K100 fuel injection Tue Nov 12, 2019 10:46 am

92KK 84WW Olaf

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daveyson wrote:Have you checked the temperature sensor, that often rescues bikes suffering from gross overfueling. For starters that the temperature sensor plug is clean and clean and clean and tight.
And DON'T use ptfe tape to seal it, it needs the metal to metal contact to function.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 51,800 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

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