K1100LT ABS2 brain removal dropped mpg to 30

[YoungEngineer]

So I've been having some recent problems with a sudden drop in mileage. My previous mileage was 45impg at an indicated 80mph (74mph) GPS. Which was never great but I accepted as good enough.




On a recent trip I noticed my mileage drop to 38impg or 31mpg at the same speeds but this time almost downhill. What I have noticed is that this happened some months after I removed the ABS computer.


I recently tried to read the computer for any existing faults and noticed that not only did the temp warning bulb no longer illuminate during power on with the other warning lights but that connecting a LED across pin 1 and ground would just cause the LED to pulse on and off in a rapid fashion.


Grounding pin 1 would however cause the temp light to illuminate telling me that the bulb was indeed still functional however grounding would cause absolutely no response from the computer. No fan test, no readouts no nothing.


Recently I saw this post which really reinforced my theory that the temp warning light may provide some insight into the health of the computer. No temp warning light, computer defaults to limp mode and a stinking rich map is used. No adjustment of the PO will make a difference as the computer ignores it completely.


Now the golden question is, is this caused by the abs2 brain being removed. Can anyone confirm this? Or is the computer damaged in some way? How could I test?

[Martin]

On the 2v Bricks a faulty temperature sender or connection can cause them to run rich. Possibly could be the same with the 4v Bricks.
Regards Martin.

[YoungEngineer]

I tested the temp sensor and it was in spec. 2800ohm cold 200ohm hot.

[Martin]

I had a recurring problem with my temperature sender. Twice it caused the computer to run the bike extremely rich, to the point of having to remove the fuel pump fuse in order to get it to start. When I first got my Brick twenty years ago, and on the advice of a mate I cleaned and dielectric greased all the electrical connection bar one. Due to the temperature senders location I didn't do it. On the two occasions it failed I managed to get my hand in there and wiggle it, this temporarily fixed it. I finally did it properly and I haven't had a problem since with it or any of my other electrical connections. Deoxit and dielectric grease or heavy silicone grease are a Bricks salvation, some inmates do not like using dielectric grease believing it can cause bad connections. My theory however is that that prudent greasing keeps out moisture and air which leads to oxidisation and bad conductivity. Your call. :dunno
Regards Martin.

[YoungEngineer]

Thanks for the advice. But the very first thing I did to the K was exactly as you mentioned. The coolant sensor connections look totally brand new. This is another issue with the computer. I am sure of it.

[jjs1234]

Thanks for the advice. But the very first thing I did to the K was exactly as you mentioned. The coolant sensor connections look totally brand new. This is another issue with the computer. I am sure of it.

I have a similar issue. I am running very rich I would guess anyway because my mileage is very low. I have a manual fan override because currently it will not turn on by itself for some weird reason. It did before I took the bike apart but now it does not. I did not get to test the relay.

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[YoungEngineer]

Stupid mistake. The app I use to calculate mpg was set to KM and not to Miles. So the calculations were way off. My current mpg is 62impg which is great. I get around 220 miles before the reserve light.

[The Mighty Gryphon]

I hate it whrn I make those dumb mistakes.

62mpg sounds like the Queen's gallon not the one we have on this side.  220 miles before the reserve light sounds a bit high.  On my bikes it comes on at 180-190.  How much fuel does it take to fill the tank when it is lit?

[jjs1234]

I had a recurring problem with my temperature sender. Twice it caused the computer to run the bike extremely rich, to the point of having to remove the fuel pump fuse in order to get it to start. When I first got my Brick twenty years ago, and on the advice of a mate I cleaned and dielectric greased all the electrical connection bar one. Due to the temperature senders location I didn't do it. On the two occasions it failed I managed to get my hand in there and wiggle it, this temporarily fixed it. I finally did it properly and I haven't had a problem since with it or any of my other electrical connections. Deoxit and dielectric grease or heavy silicone grease are a Bricks salvation, some inmates do not like using dielectric grease believing it can cause bad connections. My theory however is that that prudent greasing keeps out moisture and air which leads to oxidisation and bad conductivity. Your call. :dunno
Regards Martin.

Hey Martin, where can I get more info on this "rich setting due to the temp sensor"?

Thanks.

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[Martin]

This chart will give you the values temperatures and ohms. In both cases with mine removing the fuel pump fuse and drying out the plug and airing the cylinders allowed me to start. Do not crank over the bike without earthing the spark plugs, the chances of flash back are also high and due to the amount of fuel.  As the bike started without the fuse it was running on whatever fuel caused by the flooding. As the bike started to die, from lack of fuel I rammed the fuse back in. Two people would be better in doing this as one can work the throttle and one ram home the fuse. Once running albeit roughly it got me home. When I got home and the engine cooled down I managed to get my hand in by pushing up the radiator and wriggle the wire. This temporarily fixed the problem. I've had to do this twice until I pulled out the air box and did it properly with Deoxit and dielectric grease.
Regards Martin.

K100 Temp Sensor Values.jpg (38.1 kB . 768x464 - viewed 360 times)

[jjs1234]

This chart will give you the values temperatures and ohms. In both cases with mine removing the fuel pump fuse and drying out the plug and airing the cylinders allowed me to start. Do not crank over the bike without earthing the spark plugs, the chances of flash back are also high and due to the amount of fuel.  As the bike started without the fuse it was running on whatever fuel caused by the flooding. As the bike started to die, from lack of fuel I rammed the fuse back in. Two people would be better in doing this as one can work the throttle and one ram home the fuse. Once running albeit roughly it got me home. When I got home and the engine cooled down I managed to get my hand in by pushing up the radiator and wriggle the wire. This temporarily fixed the problem. I've had to do this twice until I pulled out the air box and did it properly with Deoxit and dielectric grease.
Regards Martin.

K100 Temp Sensor Values.jpg (38.1 kB . 768x464 - viewed 360 times)

My cooling fan also doesn't turn on by itself so I am guessing the two probs are related.

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[Martin]

JJS you need to start your own separate post. Once you do that check the site for how to check temperature relay. Also check your fuse.
Regards Martin.

[YoungEngineer]

I hate it whrn I make those dumb mistakes.

62mpg sounds like the Queen's gallon not the one we have on this side.  220 miles before the reserve light sounds a bit high.  On my bikes it comes on at 180-190.  How much fuel does it take to fill the tank when it is lit?

It is indeed. I was once told on this forum buy the crazy scientist looking guy to use IMPG for imperial and MPG for US gallon.


I am indeed getting 62 IMPG, that is highway only with 70 to 80 mpg speed. It is very high but it seems to be consistent. I have made several trip and never achieved less the 59 mpg.


When I last filled up, I had 239 miles on the trip meter and was just starting to hear the fuel pump whine.


I have just serviced the bike, new plugs, filter, custom straight through exhaust, TB sync, TPS calibrated etc.

I also adjusted the CO POT to around 380ohms which is leaner then the stock 500ohms, but the plug chop shows its happy at that setting 500ohms gives sooty plugs. Any leaner then 250ohms the idle starts to get rough.

I'm very happy with the results, the bike pulls very well and returns better mpg then other more modern models even with 97,000 miles.

[The Mighty Gryphon]

sounds like you have it tuned spot on.  Nice job!