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51Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Sun Nov 21, 2021 8:14 pm

MartinW


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The reason I have a 16v one is I ordered one advertised as BMW K75 off Aliexpress. When tested it was incorrect and was for a 16v. I sent them an email and the kindly sent me another 16v one which I gave to a mate and kept one as a comparison.
Regards Martin.

    

52Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Mon Nov 22, 2021 1:17 am

robmack

robmack
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@MartinW wrote:It's possible that depending on it's quality the meat thermometer could be slightly out. How does the temperature readings compare between the digital and the meat thermometer.
Regards Martin.
Agree.  Most meat thermometers are thermocouples rather than RTD (Resistance Temperature Detector) style sensors.  RTD sensors are significantly more accurate and significantly more responsive than thermocouples.  You'd be better off using a special purpose instaread kitchen thermometer like this .

When you took your measurements, were you heating up the temp sensor or cooling off the temp sensor?  the better way is cooling off.  Heat the water to boiling with the thermo sensor submerged and then turn off the heat source.  Start reading the temperature sensor resistance values every 10°C as the water cools.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

53Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Mon Nov 22, 2021 2:04 am

MartinW

MartinW
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If you got the readings by going off the two pins and not the pin and the body of sensor I believe you have one for a 16v.
Regards Martin.


__________________________________________________
K75s Hybrid
    

54Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Mon Nov 22, 2021 8:09 am

92KK 84WW Olaf

avatar
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The problem is consistent to a 16v temp sensor in a 2v bike too.....


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 40,490 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

55Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Mon Nov 22, 2021 11:46 pm

Holister

Holister
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@costellon wrote:Duh! Well that was 4 hours of my life that i'll never get back - but now I know.
Edit: Currently reading 2500 @ 24*c - corresponds nicely with the graph of values.
cheers
It would seem that you have remeasured the sensor correctly and are getting a correct value but I have to agree that the symptoms described does indicate a faulty temp sensor with infinite resistance at starting temperature. However, the temperature 'profile' obtained (post 44), even when measuring (incorrectly) across the sensor terminals, is inline with what you'd expect, it's just the values are double because the measurement is through both thermistors.
Having read through the whole thread it seems everything else is in order.

This leads me to the conclusion that the FICU is responding incorrectly at startup.

But a couple of questions:

  1. Where and how did you measure the temp sensor? At the sensor itself, or at the FICU plug. On a K100 its #10 and #13. Don't know if it's the same for a K75 but by measuring at the FICU plug you are ensuring integrity of the signal into the controller. Make sure the wiring is in order and the contacts at the FICU are clean.

  2. You indicate wet plugs after a failed start. What condition are they after a long run? They should be dry but if they're sooty then you've got over fueling across the range which could suggest you have a 4v temp sensor installed as Olaf has suggested.


__________________________________________________

1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  k75 Strange starting problem - Page 2 Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

56Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Tue Nov 23, 2021 5:32 pm

costellon

costellon
active member
active member
Thanks for the replies.

I scrubbed up the sensor with a scotchpad - just under the plastic section. The numbers: 0280 130 032 (Bosch) were revealed. When I cross referenced the OEM part number off the BMW parts fiche (6131145917) the results confirmed that I do indeed have a TWO VALVE temp sensor in fact, I have 2 x 0280 130 032 - which were later superseded by 0280 130 069.
The FOUR VALVE temp sensor OEM: 13622242184 - is Bosch 0280 130 055.

I have now correctly tested my identical new and old temp sensors (0280 130 032 - the results of which were identical and can be seen below) and it appears that they are functioning correctly.

k75 Strange starting problem - Page 2 Blank_10
Robmack: I removed the sensors from the bike for testing and used the boiling water method, taking my readings as the water and sensor were cooling down.
Cheers

MartinW: I used the method that you suggested and measured the resistance between one conact pin and the brass housing (ground). However - I CAN measure resistance between the pins and from each pin to ground respectively - both the old and new sensors give the same results.
Cheers

Olaf: I understand what you are saying, and thanks - but by using the oem numbers of the K75 sensor off the BMW parts fiche to find the correct Bosch part numbers it would appear that I do indeed have TWO VALVE temp sensors.
Cheers

Holister: As you can see above I have now remeasured correctly (duh) and the results appear to be good. As I mentioned above, I removed the temp sensors for testing but I have also checked pins 10 and 13 at the FICU plug (which is spotless) and am getting the same reading as I get directly from the sensor - so it would appear that the circuit is functioning correctly.
In response to your 2nd question re the condition of the plugs after a run - they are dry and sooty.
Again, due to my cross referencing the numbers from the BMW OEM parts fiche - it appears that I have a TWO VALVE temperature sensor fitted.
Cheers

Another voltage drop check yet to to be conducted as I am limited in my ability to make noise here after 8pm.

Its important to note though that when the fuel return to the fuel pressure regulator hose is disconnected and directed to a bucket - the bike fires up first time - everytime - even with a partially discharged battery .....

Any other suggestions/ advice appreciated.

Thanks again guys



Last edited by costellon on Tue Nov 23, 2021 5:47 pm; edited 1 time in total

    

57Back to top Go down   k75 Strange starting problem - Page 2 Empty Strange problem Tue Nov 23, 2021 5:45 pm

daveyson

daveyson
Life time member
Life time member
A thought bubble which just might be a quick solve or pointer at least. With two jumper wires (from battery positive to coil pins 15) your bike might start normally. It's a quick, easy thing to try.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

58Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Tue Nov 23, 2021 6:00 pm

Point-Seven-five

Point-Seven-five
Life time member
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I'm still confused about your fuel line in the bucket.

Is it the hose that runs from the injector rail that goes to the regulator, or is it the hose that runs from the regulator to the spigot on the tank?

Depending on which hose you are disconnecting, the pressure to the injectors could be very low, nearly zero, or much higher, possibly 2 bar or even higher than that.

It's possible that you have a problem with the check valve in the tank where the return line connects.  These valves have had problems that result in high fuel pressure and over fueling when starting.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

59Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Tue Nov 23, 2021 6:15 pm

92KK 84WW Olaf

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MartinW: I used the method that you suggested and measured the resistance between one conact pin and the brass housing (ground). However - I CAN measure resistance between the pins and from each pin to ground respectively - both the old and new sensors give the same results.
Cheers


Just to clarify, no ptfe tape used in mounting in the block? 


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 40,490 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

60Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Tue Nov 23, 2021 6:31 pm

costellon

costellon
active member
active member
Thanks for the replies.

Daveyson: Could you please explain further ?
Cheers

Point Seventy Five: It starts with the fuel return from the injector rack to the regulator disconnected and directed into a bucket (8mm hose that goses from the FI rack directly to the horizontal 90* spigot on the regulator). When I reconnect that hose to the FI rack and direct the return pipe to the tank from the regulator - into a bucket instead, it won't start - there are no kinks or cuts in the return to tank hose.
With the tank closed if I blow into the return pipe spigot on the tank - it pressurizes the tank and blows the air back out. If I blow into it with the tank lid open it doesnt pressurize and the air can be heard rushing into the tank. It's definitely a K75 regulator according to the part number, Vacuum hose on cyl 3 replaced with the proper flexi hose and has the coil on it - so that's not kinked or damaged. Fuel pressure measures ok. I'm currently waiting on a replacement reg from Holland - I ordered it so i'll fit it.
Cheers

Olaf: Perfect earth between sensor housing and negative terminal on the battery, no ptfe, one alu crush washer, no fiber washers
Cheers

Thanks again

    

61Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Wed Nov 24, 2021 12:28 am

Point-Seven-five

Point-Seven-five
Life time member
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Your engine will only start when there is no fuel pressure in the rail. 

You have confirmed that every part that has something to do with making the engine run is working correctly...

...And yet when you try to start the engine it won't start and the plugs are wet.  Sounds like flooding.  Have you tried cranking the engine with the fuel pump unplugged?

There is a voice in the back of my head now screaming that your ECU is not operating correctly.  It's the only thing you haven't confirmed to be working properly.  It doesn't seem to be injecting the correct amount of fuel when the engine is being cranked.  Is there any chance you can get a known good unit to try?


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

62Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Wed Nov 24, 2021 4:25 am

Arlina

Arlina
Moderator
Moderator
@Point-Seven-five wrote:It's possible that you have a problem with the check valve in the tank where the return line connects.  These valves have had problems that result in high fuel pressure and over fueling when starting.

Nah, that was at the early K100, Costellon has a K75, no valve in the return.


__________________________________________________
k75 Strange starting problem - Page 2 Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

63Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Wed Nov 24, 2021 4:43 am

Arlina

Arlina
Moderator
Moderator
Temp sensor is ok, let's focus on the wiring Smile

The violet/green wire on pin 10 of the compconnector, put your multimeter on it on lowest Ohms, take the connector of the sensor, and measure the wire, must be very low Ohms.

Then, if the wire is good, plug the connector back to the sensor, measure between pin 10 and ground, should be around 2.5 kOhm at 20C.

And, just for the record, measure pin 13 to ground, must be low Ohms too.

If that's all ok, plug in another computer from any K75, see if that will do the job Smile

k75 Strange starting problem - Page 2 260354657_1057463655072318_6755229553707503997_n.jpg?_nc_cat=111&ccb=1-5&_nc_sid=730e14&_nc_ohc=Ac2RLjj6NBUAX8GHTmR&_nc_ht=scontent-amt2-1


__________________________________________________
k75 Strange starting problem - Page 2 Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

64Back to top Go down   k75 Strange starting problem - Page 2 Empty Strange problem Wed Nov 24, 2021 5:09 am

daveyson

daveyson
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"Could you please explain further"

 I was thinking about the possibility that the coils aren't getting full battery power, but these last few posts by Holister, Point seven five, and Arlina are shaping up best at the moment, I think.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

65Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Wed Nov 24, 2021 6:18 pm

costellon

costellon
active member
active member
Thanks for the replies.

Yet again I got in too late this evening to make noise and so am limited checking the pins/ connectors as kindly suggested by Arlina.

Point Seventy Five: With the block connector from the tank disconnected the engine fires up first time every time - until the residual fuel is expended. Same with the hose from the FI rack to the regulator disconnected.
By ECU I presume that you mean the FICU (Under the seat) ? Or ICU (Box behind the steering head) ? As far as I know the ICU units differ between the K100 and the K75. Regarding the FICU for a K75 - I may be able to borrow one off a friend that lives an hour away if he's up for it, I dont know if he has an ICU.
Cheers

Arlina: Readings are as follows: Sensor to pin 10 @ 13*c - 000.0 kOhms (Ignition on or off).
Sensor reconnected, Pin 10 to ground @ 13*c - 002.0 kOhms (Ignition on), 004. kOhms (Ignition off).
Pin 13 to ground - 002.0 KOhms (Ignition on), 000.0 kOhms (Ignition off).
Cheers

Daveyson: Cheers

Edit: Olaf: Cheers for confirming that, I just had a look at the parts fiche

Yet again, thanks to everyone for their time.



Last edited by costellon on Wed Nov 24, 2021 6:28 pm; edited 2 times in total

    

66Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Wed Nov 24, 2021 6:23 pm

92KK 84WW Olaf

avatar
Life time member
Life time member
K75 ICU and FICU are not interchangeable....physically look the same..


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 40,490 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

67Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Thu Nov 25, 2021 12:09 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
ECU is the Engine Control Unit.  It's the one under the seat and is specific to the three cylinder K75.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

68Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Thu Nov 25, 2021 10:41 am

92KK 84WW Olaf

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Post up the part no thats stamped or on a sticker on the Fuel Injection Control Unit under the seat. Its K75 specific. It may have a Bosch or BMW part no on it.

You have successfully tested most of the things that can cause issues but I am not sure if you have tested the temperature sensor at the plug end which would reveal if there is a break in the wiring, not unheard of.


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 40,490 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

69Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Thu Nov 25, 2021 11:20 am

Point-Seven-five

Point-Seven-five
Life time member
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@92KK 84WW Olaf wrote:You have successfully tested most of the things that can cause issues but I am not sure if you have tested the temperature sensor at the plug end which would reveal if there is a break in the wiring, not unheard of.
+1

We've asked for you to check the resistance across pins 10 and 13 of the ECU connector, and so far, you haven't responded.

You report that there is ground on pin 13, and continuity from the sensor connector to pin 10, but no confirmation of the resistance across them when the temperature sensor is connected.  It's such an easy thing to do it should have been done already.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

70Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Sat Nov 27, 2021 2:39 pm

costellon

costellon
active member
active member
Apologies for my not having responded since wednesday - I am a Mariner and have been at work - AT SEA - with NO INTERNET - once i'm over 15 miles or so from land I have no phone signal - and as a consequence - NO INTERNET. I cannot justify buying a sat phone/ link as its way down my list of priorities and anyway, I enjoy "cutting the cord" - that's part of why I do what I do.

Anyway, i'm ashore again until the next tide. Tonight I will be sailing and will not be coming ashore until next Saturday morning, so please exercise some patience regarding my responses or lack of therein. Thanks.

Olaf: In previous posts I stated that I tested both connectors from the temp sensor for continuity to their respective pins (sensor to pin 10 on FICU, sensor to pin E of temp control relay and pin 9 on temp relay to fuse 6) but I didn't state resistance.
I grabbed a pic of the FICU (see below) and noticed that it has a different bosch number to the one on my last K75 .... are all the K75 FICU's interchangable ? I'm wondering why some have different part numbers ....... doesn't matter.

k75 Strange starting problem - Page 2 Img_2010
Cheers.

Point Seventy Five: "I have also checked pins 10 and 13 at the FICU plug (which is spotless) and am getting the same reading as I get directly from the sensor" - from post 56 ...... I.E. Pin 10 to pin 13 on FICU @ 13*c - 002.0 kOhms (Ignition on), 004. kOhms (Ignition off).
Cheers

Thanks again, have a good week

    

71Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Sat Nov 27, 2021 2:45 pm

Arlina

Arlina
Moderator
Moderator
As far as I know (and did) are all K75 FICU interchangable.


__________________________________________________
k75 Strange starting problem - Page 2 Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

72Back to top Go down   k75 Strange starting problem - Page 2 Empty Strange problem Sat Nov 27, 2021 5:00 pm

daveyson

daveyson
Life time member
Life time member
OK, scraping the bottom of the barrel, but the tides coming in, and it's a quick check. 

With the throttle in the fully closed position, you should hear a faint click at the rear of the throttle bodies when you slightly turn the throttle.

The throttle switch, between the throttle bodies and coils, could be sending a false enrichment signal to the fuel injection computer. Your brick might start if you unplug it.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

73Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Sat Nov 27, 2021 6:41 pm

costellon

costellon
active member
active member
Arlina: Thanks for that

Daveyson: I already reset the TPS, tried it whilst both connected and disconnected - no change. I then got another one off a K100 (same part no), fitted it, reset it and also tried that unit whilst connected and disconnected - no change. Tide's in, i'm out !
Thanks all the same.

Another little experiment I tried today. If I fit clean and dry spark plugs - it'll start first touch of the button with no throttle. Once I stop it and try to start it again i'm back to the original problem.

Yet again, thanks and have a good week/ weekend

    

74Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Sat Nov 27, 2021 7:18 pm

Laitch

Laitch
Life time member
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@costellon wrote:I grabbed a pic of the FICU (see below) and noticed that it has a different bosch number to the one on my last K75 .... are all the K75 FICU's interchangable ? I'm wondering why some have different part numbers ....... doesn't matter.
I'm wondering if the last sentence in the quote above is a conclusion you have drawn, or a query. Both Bosch and BMW change parts' numbers occasionally. In a BMW parts fiche, the superseding part number is indicated. In the fiche, two ficu units have been listed. The reason for changing the number could be from a tweak to its manufacturing, or an inventory re-configuring. Either part will work—as Arlina indicated. BMW has a long history of installing mid-production remodeling that is interchangeable.

If you have determined all the values measured at the fuel injection control unit plug are close to those outlined in the troubleshooting guide found in the Portal here, it's time to start testing the ignition control unit following the troubleshooting guide.


__________________________________________________
1995 K75 81,000 miles
k75 Strange starting problem - Page 2 Usa-lo10
    

75Back to top Go down   k75 Strange starting problem - Page 2 Empty Strange problem Sat Nov 27, 2021 7:27 pm

daveyson

daveyson
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I'm also guessing it's something not important. Maybe it indicates which factory it's made in, I think the label says made in Spain.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

76Back to top Go down   k75 Strange starting problem - Page 2 Empty Re: k75 Strange starting problem Sat Nov 27, 2021 8:03 pm

92KK 84WW Olaf

avatar
Life time member
Life time member
They have a Bosch part no and a BM part no,...


__________________________________________________
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 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 40,490 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 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
    

77Back to top Go down   k75 Strange starting problem - Page 2 Empty Strange starting problem Sat Nov 27, 2021 8:26 pm

daveyson

daveyson
Life time member
Life time member
Actually, 376 indicates it's an ex cop bike. There might be other signs of that, like bulky earth straps, one to the tank for example. The only brick I have with a fuel injection computer  with the last digit 6, Is an ex police bike. 

My k75 has a red sticker ending 332, yours, police, is blue.

You might see some signs that the bike was white, a net search of the Vin number might even show that it's original colour was police white. But you're right, that doesn't matter.

Can you tell us a bit about its history, and what colour it is now? . Do you have bare metal (paint scraped away) at all earth points?

I like the idea from Laitch that it's time to test the fuel injection control unit using Bert's guide. Your friend with the k75 would probably be more interested in trying your computer in his bike than the other way around, in case your brick cooked your computer.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

78Back to top Go down   k75 Strange starting problem - Page 2 Empty SORTED Today at 3:34 pm

costellon

costellon
active member
active member
What a week !!!

Yet again, thanks to everyone for their comments, advice and time.

I bit the bullet last Sunday night, logged on to Thom Hellbrekkers - kpartsholland website and purchased a 2nd hand FICU - it cost €80 including shipping to Ireland, not bad. I got an identical unit with the blue label - part number ending in 376.
My neighbours intercepted my parcel yesterday and gave it to me a few hours ago. I lit the fire in my shed, poured myself a nice cool tall glass of hefe Weissbiere .... delicious !
I then plugged in my replacement FICU/ Jetronic unit, turned on the ignition, pressed the starter button and the engine fired up in the first second. I stopped it, started it half a dozen times - perfect! To be sure I then refitted my old FICU, turned on the ignition and hit the starter - engine turned over but didnt start - not even a random fart - nothing. I put the replacement unit back in, ignition on - hit the button - fired up staight away - result!

I'm currently putting it all back together and will hopefully get out for a burn in the morning. It would seem that I have rectified the problem - I should be 100% sure by this time tomorrow.

Daveyson: The bike is indeed an ex police bike, earth straps all over the shop, two extra relays in the relay box and a load of auxillary wiring (which I removed when I had to replace the wire from the solenoid to the starter as well as some other melted wires - which I now assume damaged my original FICU).
The bike is painted Anthracite black and appears to have came like that from the factory - some small panels appear to have been repainted and going by a few scratches, the tail piece originally came off a red bike - probably to replace the police/ original unit - maybe someone replaced all of the panels and tank - who knows - I like it in black. All of the fixtures and fittings for the fairing parts were 100% original - it seemed that it was once well looked after and unmolested. Maybe it started out black and was perhaps used in its black livery as some kind of another Government/ emergency services/ law enforcement vehicle. It came with nice tidy City cases and is fitted with the original grey seat that came as standard on the black K75RT's from the early 90's. It looks pretty stock and reasonably presentable - except for the barn door sized screen that I fitted that I had left over from one of my past K builds (winter protection). I got the bike off a guy that got it as a non runner off another guy in Cork - there was no history with the bike and it was about 99% complete.

Tomorrow will tell all - but so far so good, I'm hoping to head to the Delphi Valley and do a few runs ... https://vimeo.com/653464912 (My old R80 GSPD "Panzer")

Thanks again to everyone - top class bunch of people - much obliged



Last edited by costellon on Sun Dec 05, 2021 4:23 pm; edited 2 times in total

    

Arlina

Arlina
Moderator
Moderator
Good to read Smile
Now we're curious if the bike will run fine tomorrow Very Happy


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