BMW K bikes (Bricks)

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Cleverbee

Cleverbee
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Dear Forum, For the last 2 months I've been trying to sort out why my LT suddenly started running bad.  It started whilst on a run out when I noticed the engine braking wasn't as it should be, I'd shut the throttle and the engine would tick over around 2000 rpm, but intermittently....
After that cold starting is only achieved by turning the starter whilst holding the throttle fully open - without choke.  Once firing choke to first detente and throttle held slightly open, very lumpy and smokey until some heat is in the engine, then runs fine, but fuel economy poor.  When it is warmed up, occasionally when held at 1300 rpm, the revs suddenly increase to a tad under 5000 rpm !!! - close throttle slightly and revs return to 950....
So far I've replaced plugs twice (black and wet on removal), drained and refueled tank, changed the Air Flow Meter, changed Coils and plug leads, checked K&N filter - no excess oil, oh yes, stripped the Throttle Position Switch and found OK, but fitted a brand new one anyway.  All circuits appear OK, new Fuel Pressure Regulator was fitted last year, vacuum hose replaced.
At my wits end now, taking my life over trying to find the cause, anyone got a nice brick wall to bang my head on - I've used mine to excess  Mad Mad Mad

    

RicK G

RicK G
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Check your valve clearances it could be tight inlets.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

Cleverbee

Cleverbee
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Rick,  thanks for that, but I re-shimmed the bike 6k ago and it ran like a sewing machine until now, something sudden has happened to it.  Motorworks (UK) suggested it could be the earths for the injectors so that they spew full fuel all of the time, Barrie Robson (BMW York) suggested the Temperature switch - it was replaced last year with a brand new one - doubt it has folded in a year...?

    

charlie99

charlie99
VIP
VIP
the sensor might be ok ...but the connector may have corroded up again ...worth pulling apart to test clean
you can test the connection to the temp sensor by pulling the connector from the under seat computer and counting from the left to all the holes till pin10 is the sensor pin 13 is the earth to that ecu ...measure with ohms range set to 10,000 ohms ....cold should be about 3000  ...if higher  suspect the temp connector or earth to it at first instance ...else delve deeper

likewise check the connector with engine warm  same deal but the resistance should have changed quite a bit lower

hope that helps

there is a graph for this in the efi troubleshooting thread  if you look it up

cheers


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O1988 K100LT - Running Rich - Poor Starting - End of Tether !!! Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

Holister

Holister
Life time member
Life time member
@Cleverbee wrote:....  Motorworks (UK) suggested it could be the earths for the injectors so that they spew full fuel all of the time, .....
The injectors are switched to earth by the FICU so I doubt that's the problem. The Jetronic is a very reliable unit so I would be looking elsewhere first off.

It certainly sounds like a fuel injection issue but likely to be corrupt signal from a sensors so...
+1 what charlie said, but if no joy there then do a proper load test on the battery. You'd be surprised. This can play tricks with the FICU.


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1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
  1988 K100LT - Running Rich - Poor Starting - End of Tether !!! Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

nino

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Probably broken fuel pressure regulator. After sam symptoms I checked everything I can remember. Finally I replaced FPR with spare one from my garage and everything became normal: no black spark plugs, normal consumption, idle as before.
Regards

    

charlie99

charlie99
VIP
VIP
good point nino  worth remembering


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O1988 K100LT - Running Rich - Poor Starting - End of Tether !!! Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

nino

avatar
Life time member
Life time member
Problem with FPR is position behind all that boxes, filters, etc. I rerouted FPR on this position https://www.k100-forum.com/t8064-fuel-pressure-regulator-rerouted

    

Cleverbee

Cleverbee
active member
active member
Good ideas gents, thanks.

Armed with multi-meter and old FPR I shall bury myself in the garage once more.....

What's that saying....? Patience is a virtue, hmm, let me think about that one !!!

    

Cleverbee

Cleverbee
active member
active member
Right then, here's one for the number crunchers that understand more of multi-meters than I do....!!

Measured Pin #10 on the EFI plug to ground with multi-meter set at 2M = 1.03k.

Removed r/h side fairing, checked resistance of Temp Sensor plug to EFI  i.e cable = NO RESISTANCE 

Measured resistance on the pin of the Temp Sensor that goes to EFI pin #10 to ground = 1.8k

Measured opposite pin of Temp Sensor to ground = 0.331k

Measurements taken of engine block on cold engine = 17.3 deg C - According to the graph, should be looking at a reading of at least 3k ???

One bonus (sorry Motorworks and Motobins) found alternative sensor using realoem's part listing on Amazon search - http://www.amazon.co.uk/FAE-33090-Sender-coolant-temperature/dp/B00DQEWR9O  for the brilliant price of £13.26  Very Happy

Not checked/swapped FPR yet, awaiting Forum conclusions.

    

nino

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Before start to dig in direction of FPR, measure pressure inside fuel system. It has to be 2,5 bar, or 36 psi. Over pressure means black spark plugs, higher idle, higher consumption.

    

12Back to top Go down   1988 K100LT - Running Rich - Poor Starting - End of Tether !!! Empty MISSION ACCOMPLISHED Fri Jun 26, 2015 2:17 am

Cleverbee

Cleverbee
active member
active member
Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy Very Happy :DNew Water Temp Sensor arrived and fitted, now purrs like a pussycat !!!

First time the Injection System has fouled up - it has been a pain to resolve, but thanks to all who have helped, who'd have thought eh, a simple switch....... or a simple rider  Embarassed Embarassed Embarassed Embarassed Embarassed

    

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