Fueling musings from the doc

Dr Bones

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OK, time to add my thoughts and findings to the cat code plug / TPS / CO pot conversation.

My 97 R1100GS came with a beige CCP fitted. When I got it it surged badly at lower speeds and lacked any grunt above 70mph.

Did all the usual things, set the valve clearances, replaced the O rings in the intakes, cleaned and balanced the throttle bodies (and set cable slack) and set the TPS to 0.361v.

These things made some difference but I wasn't happy, so I continued. I set the CO pot (on a meter to 1.7% and set the TPS to 0.385v. The surging was better, but still noticeable, but the top end was still weak.

By this time I was fed up trying to poke bits of wire in the TPS to connect to the voltmeter so I made this:

tpstool1.jpg


tpstool2.jpg


tpstool3.jpg


tpstool4.jpg


tpstool5.jpg


It's the TPS connector from an old loom with some small insulated crocodile clips and some terminals attached. Connects to the bike in seconds. I guess if you haven't got an old TPS plug a 4 way female junior timer connector might fit?

The next step was to pull the CCP completely. What a difference the surging was going and the bike pulled strongly well past legal limits. But the fuel economy suffered. So I've applied some logic to this, higher TPS setting means richer mixture and having no CCP already makes things rich. So I set the TPS back to the lower end of it's limit at 0.320v.

I took the bike out this evening and the first thing I'd noticed was the RID temperature got up to five bars (with no CCP before it only made four). There was very slight (but bearable) surging at low speeds and the bike pulled hard past 70mph. The bike idles pretty well at around 1000rpm and the CO reading settled at 1.9-2.0%.

I have to do a 180 mile round trip tomorrow (mostly motorway) so I'll report back on the fuel economy.

0.320v TPS and no CPP, anyone else tried this?


Sorry if this post was a little long. I'm a scientist, which make me inherently boring in some peoples eyes and I have a tendency to analyse things at a level which is probably not necessary sometimes :D
 
Sorry if this post was a little long. I'm a scientist, which make me inherently boring in some peoples eyes and I have a tendency to analyse things at a level which is probably not necessary sometimes :D

Not at all. I think you do yourself a disservice. There are far too few people who understand things from first principles, these days. Good luck with your further enquiry....:thumb2
 
Hmm.
Which sparkplugs are you using, out of interest?

I forgot to mention those, I'm using EON2's, I changed from the two electrode NGK ones, again they seemed to help the surging a little, but nothing amazing. I'm beginning to think that getting these bikes running perfectly is the sum of lots of little parts. By perfectly I don't mean like a four cylinder bike, my other bike is a MK1 Yamaha TDM 850, which is a joy to ride (I love the torque) After tomorrows run on the BMW, I'll pull the plugs to see what colour they are.
 
If I understand it correctly, the beige CCP tells the ecu to look for a co pot. Therefore, removing the ccp completely will do the same as unplugging the co pot and cause it to go into a 'default' mode.

As an aside, if you're being this fussy (not complaining - been there, done it) then a throttle body rebuild will work wonders for the low speed driveability.

Dick
 
What's the map of the beige one please? I've a co2 pot. Ive not had a ccp in mine for years and wonder...
 
If I understand it correctly, the beige CCP tells the ecu to look for a co pot. Therefore, removing the ccp completely will do the same as unplugging the co pot
Dick

I don't think so... no CCP in my 99 1100. and the co pot works just as it should.

I've never had surging either.. not on this 99.. nor my previous from new 97. I'm always surprised to read about surging these days.. i thought this was an issue that was sorted donkeys years ago. sorted with nothing more complicated than the bike being properly set up and serviced. No 'special' spark plugs or anything like that

there's a chap here in nottingham who could sort your bike out..

Or.. alternatively ride it down to london and let Steptoe set it up for you. Once done the bike should serve you well for decades.
 
To stop you wasting your life it's all been done, conclusions reached and posted before - try a search. :D

Here's a couple of pictures from previous threads



Attach some long reach spade ends.




Plug it in-line between the TPS and the bikes TPS plug.



And measure the voltage off the exposed long spade connectors.

 
To stop you wasting your life it's all been done, conclusions reached and posted before - try a search. :D

That's the problem, I did a search and got as many answers as there were questions...

TPS at 0.361 , 0.371, 0.385, 0.390, 0.400

CCP in, CCP out, CCP different colour, CCP use some wire to bridge ...

Use these spark plugs or these.....

Use standard BMW air filter or use K&N

All these bikes although fundamentally the same seem to react slightly differently to adjustments to each other. Now I'm not trying to reinvent the wheel, I'm just trying to apply some logic to see what works best for my bike. I know you work on these bikes all day every day and I could (and still might) bring the bike down to you and you'd fix it instantly. But I'll never learn anything by just paying someone to fix it, plus there's no enjoyment in that either for me.

:D
 
Yes, I'm with you on that...
My R1100R is being very petulent on the surging issue. In the old days with paying customers I was generally happy how they went out the door. This R is a bee-atch.
My own thang is not to put a 'Champion' in anything but that's just me.
I found that the twin electrode Bosch plugs were really, really bad for surging. Swapping them for NGK platinum greatly reduced the problem. Nothing else adjusted.
I've just put a pair of Brisk plugs to see how they compare to the NGK plugs.
The big alteration on mine is a GPR exhaust which has knocked the mixture for six and it's still a bit on the rich side, but we're getting there.
 
OK results in

180 miles which was mostly motorway. I kept to normal motorways speeds apart from giving it the beans on a few overtakes etc

I used 15.46 litres of fuel, which works out as 52.93mpg.

The plugs have a small amount of colour to them (which maybe doesn't show up too well in the photos) and I think I could richen things up a little (maybe 0.33v or 0.34v on the TPS).

Left Plug

left320noccp1.jpg


Right Plug

right320noccp2.jpg
 
Yes, I'm with you on that...
My R1100R is being very petulent on the surging issue..

Try checking the resistance across the injector terminals.

Should both be around the 16 mark, any lower or higher and you'll have an imbalance which causes surging.

Different types of spark plugs make bugger all difference to how these engines run. Do you know how double/triple electrode plugs actually work ?
Any noticable improvement is just down to the fact you've fitted new plugs and dumped the old ones :D
 
hard to tell from the pics but there is no colour to those plugs - yet the outside is sooty ( or hot,dried oil deposits ) ?


i'd say you were a bit too weak judging by the mpg figures - but who knows how you ride ?

you do know about the big brass idle screws too ?
 
Thanks Steptoe, I'll check the injectors, but they should be OK as they are just back from cleaning and testing by the Scriminger people. I agree with what you say on spark plugs that spark plugs shouldn't make a difference, and I understand the multi electro design (the spark only ever uses one electrode at a time). But research does show that shrouding of the spark by the electrode(s) can in theory make a difference. My plugs definately show that the engine is running a little lean, the photos don't show it well but there is a very light brown colour on the insulator. I didn't ride like a hooligan yesterday and most of the milage was steady motorway. I'm going to adjust the TPS a little further and retest. Originally with no CPP and the TPS set at 0.361v the bike definately had that 'soggy' rich feel to it and the fuel consumption was awful. What I am trying to demonstrate here is that although we can't change the fuel and ignition mapping, without reflashing the ECU or installing a new chip, we can change the relative position of a map point in the maps which is based on engine rpm x throttle opening (which is just used as a calculation for air flow). So to give an example if the bike surges at 3000rpm at a throttle opening of 10%, increasing the voltage on the TPS will change what the ECU thought was 10% to perhaps 15%, meaning a setting higher up the maps is now being used (more fuel and poss more spark advance). The original map point which caused the surging hasn't gone away, but now it's in an area of the maps you don't hit much (if ever) so it's not as noticable. Obviously there are other ways to influence the fuel and spark advance, by modifying the signals from other sensors, usually the temperature ones. Again the maps don't change, but each point in the map can be influenced (by the extra input from the sensor - resistor). In reality there are two posssible stock map configurations I can use, the beige CCP or no CCP plug, all other plug colours relate to O2 sensor bikes (which mine doesn't have). The beige plug map causes surging and has weak top end, no CCP make the bike run really well, but consumes lots of fuel. By tweaking the TPS, I can run with no plug, all but eliminating the surging from lower down the rev range, but still maintain some reasonable fuel economy. Yes it's a hack, but no more so than adding a resistor to the temperature sensor.

thanks for everyones input on this

:thumb2
 
Like our man above, i'm aware of the way the plugs fire Steptoe. But the 'old plugs' were Bosch ones that had been in for less than 100 miles.
So how do NGK iridium plugs alter the way the bike runs, lessening the surging and farting with no other change, on the same fuel if they are all the same..?
Yours on an N9Y.

I will check the injectors though cos its starting to annoy me now.
 
0.320v TPS and no CPP, anyone else tried this?


Sorry if this post was a little long. I'm a scientist, which make me inherently boring in some peoples eyes and I have a tendency to analyse things at a level which is probably not necessary sometimes :D

Thanks for your post Doc, I like the detail and analysis :)

I recently did a zero-zero balance to try improve the surging issue. Only afterwards did I remove the CPP - actually just a piece of wire, but making the same connection as the beige plug. I was amazed at the difference on my 1100GS ('95 with Remus can) - no surging and far better throttle response all through the range. As you say the fuel consumption has dipped and the plugs are definitely sootier than before. After reading your post I think I'll redo the zero-zero balance procedure, but drop the TPS voltage a little and see what difference that makes to mpg.

Thanks again :thumb
 
I'll grab a couple of these tomorrow to have a play with :thumb2
 

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