1100GS Real bad fuel consumption

  • Thread starter Thread starter dazco
  • Start date Start date

dazco

Guest
1996 1100Gs with 55k on clocks. Runninng with standard BMW exhaust and road tyres.
Im getting P--- poor fuel consumption, between 130 and 150 to a tank full , thats on about 20 litre of fuel.
over the last week or so ive replaced the air filter, plugs done the valve clearences and rocker end float, Balanced the throttle bodies etc etc, basically a good tune up.
The bike runs super smooth, starts on the button every time, idles fine(no cutting out at low revs)
Does NOT back fire or pop.
Accelarates as good as ever and pulls like a good un.
The plugs are both BLACK, sutted up after 20 miles.
Ive seen some mention about a co2 sensor somewhere but cant put my finger on it now i want it.
Any ideas???

I thought it might have been an injector playing up after reeding a piece by Steptoe, however with both plugs being in the same sutted up state this would indicate both injectors were playing up. (What are the chances of that)
Or am i missing something else much more simple?
with the cost of fuel now its starting to get expensive to get to work and back:eek:
Thanks Dazco
 
Excessive fuel consumption = too rich mixture.
Plugs black = too rich mixture.

Various possible causes: faulty Lambda (O2) sensor / worn injection heads (doesn't properly "spray" anymore) / and also small chance of too weak spark (bad ignition coil mayhaps)

Reset Motronic for a start (pull fuse no.5, then put back, ignition on, roll throttle fully ON and OFF 2 times and switch ignition off again, reset done).

IF your bike has a Lambda sensor, then it is locaded beneth the engine, just beneth the gearbox drain plug, in the big "boxy" part of the exhaust, you SHOULD see 2 cables go there and you should see the sensor going into the exhaust. See if the cablig and connections are OK on both sides (you need to remove the fuel tank to check the other end - there's socket, open it and clean the connections - they're maybe rusty making bad Lambda(O2) sensor connection that's causing you a bad fuel consumption )

Your bike can be w/o Lambda sensor too.

In any case, if no better running after that, then pull out the Cat Code Plug (CCP), reset Motronic again and see how it runs. Removing CCP say the Motronic that it'll run w/o Lambda sensor.

Let us know how it goes! Then we're maybe a bit smarter on diagnosing the fault :)
 
Thanks for that Tsiklonaut Bike does NOT have a Lamda sensor.
Will try the Motronic reset tomoro, Clean plugs (Again) and then fill with fuel and see how it goes over the next week.:thumb
 
The mixture is set with the CO pot, accessible on the r/h side under the rear mudguard there's a hole. Look up into it and you'll see a big screw.

If you don't have a co meter turn the screw 2 turns clockwise to start with and see how it goes.

But it could also be your airsensor.
 
ill try the motronic reset, then start with the co2 mix after i see how its going.
The air sensor, that is the one on top of the air filter housing i asume, is it worth just buying a new one or are they adjustable?
Ta
 
A TPS can cause high fuel consumption if it isn't set correctly, or it's gone wrong.
 
Basil could you tell me which model of super reliable KTM is best?.
Plans are afoot:augie
Ive re set the motronic and done the plugs, ill see how it runs this week before changing anything else. Dont want to get too bogged down and start messing around with more than a copuple of things at once
Thanks
 
I had the same problem on my 1996 1100gs it turned out to be the TPS unit was intermittently faulty so it was a right bugger to diagnose however a good 2nd hand unit fixed the issue, it runs like a dream now.
 
Steptoe said:
A TPS can cause high fuel consumption if it isn't set correctly, or it's gone wrong.
Click to expand...

That's the case with mine.... I fitted a new TPS and set it up by hand/ear.

The bike pulls very well but it's using about 20% to much fuel.

I've tried setting it up with a meter but I never seem to get the readings I'm looking for so it's been left... Time to dig through the old threads and have another go.
 
Wreford Miles said:
That's the case with mine.... I fitted a new TPS and set it up by hand/ear.

The bike pulls very well but it's using about 20% to much fuel.

I've tried setting it up with a meter but I never seem to get the readings I'm looking for so it's been left... Time to dig through the old threads and have another go.
Click to expand...

I fitted a used Left side throttle body not long ago, unfortunately the throttle stop had been disturbed so the normal TPS setup was a no go, I ended up using the Rob Lentini Zero Zero setup as given on IBMWR, at this point Steptoe usually chimes in and tells me that he has never needed to perform this:eek:, but for me it was the only thing that made the bike run properly, after an admittedly gentle ride this weekend my full to full tank consumption worked out at 55 MPG, normally around 45 though.

Stewart:thumb
 
Stewart H said:
unfortunately the throttle stop had been disturbed
Click to expand...

I'll chime on and say that's a completely different scenario to someone who just happens to have read something on the internet and decides to mess their bike up.

i expect the original owner tried a zerox2 and thats why you've ended up buying it secondhand. :augie

Also the man who started this thread "may" have a problem with his bike. Starting to then piss around moving things that can upset a bike more than cure it will do him no good whatsoever, especially if it has got a problem elsewhere.

It's very simple - Never introduce something else into the equation when your trying to diagnose a possible fault.
 
Steptoe said:
I'll chime on and say that's a completely different scenario to someone who just happens to have read something on the internet and decides to mess their bike up.

i expect the original owner tried a zerox2 and thats why you've ended up buying it secondhand. :augie

Also the man who started this thread "may" have a problem with his bike. Starting to then piss around moving things that can upset a bike more than cure it will do him no good whatsoever, especially if it has got a problem elsewhere.

It's very simple - Never introduce something else into the equation when your trying to diagnose a possible fault.
Click to expand...

I agree totally, when fault finding only make one change at a time, and with a machine that has just stopped/failed everything thats okay is not the problem:thumb

Stewart
 
Just to bore you all, done 50 miles, 2 days of traveling to work and back and the Gauge has dropped 2 bars. so far so good.
If it stays like this ill be havin some :beer: at the weekend from the money saved on Petrol.
Ta Dazco
Ill bore you all again on Friday and tell you how its gone
 
I've got exactly the same problem with my bike ie excessive fuel consumption. So bad that I had to buy the 41 litre tank just to get a reasonable range:)

I took it to the dealers Ocean and they diagnosed the throttles needed balancing but no difference after that was done. Second visit was for airbox temperature sensor. Replaced that, no difference. Next they suggested engine temperature sensor so that was replaced as well but still no difference. Two more visits and over £500 later and bike was still exactly as bad as when I first took it in.

I have now taken two courses of action:

1. Bought KTM and will be using that at Hograost this weekend:D.
2. Contacted Steptoe and arranging to drop off bike to him for some proper TLC by an expert.

With the price of fuel these days, I can't afford to waste it.

Sid
 
Told you id bore you all again,
Just finished my first tank of fuel since the throttle balancing etc etc and its returned 40.1mpg, this is all comuting so plenty of stop/ starting.
Not as bad as i first thought it was gonna be. Im gonna do the boddies again at the weekend and check the plugs for colour etc and mioght check the TPS voltage.
Has Steptoe written an easy guide to this(ive looked and searched but cant find anything) ive read some other guides(American) and found that after ive read the first 16 pages of waffle ive missed something:augie.
Thanks for all the input so far.
Dazco
 
Cheers Stewart.
ill be trying that at the weekend.
Its definately better than it was but still not as good as it was.
Thanks:beer:
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
You must log in or register to reply here.

Similar threads

Attempted theft, lock barrel and BAD fuel consumption
Replies
8
Views
1,577
poyton


Back
Top Bottom