ABS II problems,(yes another one)

ABS II problems, now solved with a low cost sensor

The back story first, I bought my ST as a fixer upper last year,
it had most of the big pan problems, alternator, swingarm, carb diaphragms etc
anyway the abs lights were on,
i retrieved the fault codes which showed a rear crank angle sensor failure,
i stripped the rear pump and sure enough the rear angle sensor wasnt giving the right readings,
i fitted a new sensor(the pump itself appears to be fine and works when voltage fed to it)
did a full reset to clear the code, bled the brakes and took it for a spin,
now heres where it all comes unstuck, the abs lights remain on, they flicker a bit when i brake, when i check for codes i just get one long flash which i take to mean no faults stored, the bike has a new battery and a rebuilt alternator and gives a good 14.5 volts even with the lights on,

I figured with the wealth of experience on here, someone may have come across a solution to my problems.
Thanks for reading this, if anyone can help i'd appreciate it,
this bike has been threatened with a half hundredweight of thermite and still wont behave itself

Sounds like it might be a bad ABS computer. Have you checked all the harness connections to make sure they are fully seated? Do you know anyone with a good working ABS II system where you could swap out the comptuers to see if the problem follows?

Abs models are scarce here, most bikes are non abs, ill try to find one in a breakers and see what happens,
i've had a thought that it may be an earthing problem, the lights flicker a tiny bit if i brake or turn on the lights,

ah well, back to the shed for a while

Jim - If the earth is messed up, it will definitely 'tinker' with the ABS function. You've probably already checked, but the earth battery cable tends to work loose if routed through the hook on the side of the battery box.

I only fitted a new battery last weekend but ill double check the connectors. From what i've read on various sites last night bad electrical connections could well be the source of the problems, ill check those and see how it goes

Jim, I'm currently suffering from an ABS II problem as well. Check with Norm over at My-MC.com, he's pretty much the ABS guru...

George said:

Jim, I'm currently suffering from an ABS II problem as well. Check with Norm over at My-MC.com, he's pretty much the ABS guru...

Click to expand...

Thanks george, things took a turn for the worse tonight, i took the bike to a rally and about 10 miles from home everything goes dead, lights, motor the lot, thankfully there was no traffic about,
anyway i pushed it to a small village and got the toolkit out,
the sidestand switch seems to be the culprit but how that happened is a mystery, i can understand it killing the motor but not the lights,
I got the lights working but had to short the neutral to get moving,
I'm beginning to think theres some serious wiring issues with this bike, and the abs problems may be related,
ill keep ye posted,
Jim

Had a quick look this morning, the sidestand switch is good but the switch seems to be earthing a good portion of the electrical system, sometimes.
I notice from the wiring diagram that there is a common earth point which must be loose or corroded,

does anyone know where its located, might save me stripping off more plastics than i have to.

Jim, the common earth is the "far end" of the battery negative cable, bolted to the engine block just in front of the starter motor. If you had corrosion at the battery end, might be some there too.

Also, good idea to ruff up the "inside" of the battery cables where they contact the battery, both positive and negative. Folks often forget that.

There is anther common ground but don't recall where it terminates. It has both a Green (common ground lead) and a Green/Black (ground lead for fuel indicator check unit, fuel level unit in the gas tank, and the temperature gauge.)

I suggest finding a green wire and/or one of those green/black wires and doing a continuity check with a digital multi-meter to the engine block. Zero Ohms would be best, more than one or two ohms indicates high resistance ground which could be part of your problem.

John Oo (John OoSTerhuis at both sites) has a full color wiring diagram over at st-riders.net. Worth joining at that site but ya need a STOC number to do so. Apply at st1100.org, number will pop up quickly.

There are reasons to belong to each of the sites, this one has most contacts and most events liSTed, the others each have something unique to offer. Don's site (st-riders) is the culmination of the original STOC e-mail site, st1100.org is the original European site by STeinar Fromme (supplanted now by My-MC.com) and now this site. Subscribe to and use them all.

And contribute. Keep us poSTed on what ya find...

Keep us poSTed.

Thanks George, the battery neg connection to the block is good, its the one where the green and green black wires terminate i need to find,
i did a little experimentation and found that if i connect the green wire for the clocks to the battery negative everything fires up nicely which points to that earth connection, however with lights theres over 8 amps of load on that wire so i cant really use it as a quick fix, ill have to find the source of the problems,
i'm also beginning to suspect i have a police loom on the bike, theres a lot of odd connections there but the history check came back as never having been a police machine,
the colour wiring diagrams i have myself already but thanks for the tip

When ya find that ground point, let us all know.

I think there's a grounding point just behind the handle used to aid in lifting the bike to the centrestand.

Just checked the service manual. Point above is labelled "frame ground".

Found it this morning, or what was left of it anyway, i relocated it to the battery negative, lots of problems sorted but not the abs, lights are still coming on
Rossi is dead right about the ground point,
are there any others rossi?

I'll check that point on my bikes too. Still suffering an ABS II failure on lipSTick...

Thanks for the info, Rossi.

Ok some progress finally, with the ground issue, plus a litany of other electrical problems, i tried jheaths reset to get the lights flashing, it now flashes for the front wheel but not the rear.
I can make it do something if i wiggle the wires going into the sensor, i get the occasional flash, i've been looking online and those sensors are expensive, i thought the angle sensor for the modulator was expensive,
ill have to see if i can find a used one

Edit: Does anyone know if the early and later pans use the same sensor, the part number seems to be the same

Far as I've been able to find, the sensors are the same on ABS I and II...

George said:

Far as I've been able to find, the sensors are the same on ABS I and II...

Click to expand...

Excellent, i know a guy with an abs I with the abs removed, hopefully the sensors are ok,
did you get anywhere with your machine george?

jim'll break it said:

...did you get anywhere with your machine george?

Click to expand...

Not yet. I've ridden nearly 10,000 miles without the ABS so not too concerned right now. Other things have my attention.

Well, the gods of motorcycling decided against the job going easily, the mounting bracket broke when i was removing the old sensor,

I think i might see what other 3 wire sensors i can find that might work instead of forking out €362 for a new one, maybe i can make a standard cherry sensor fit

I have been doing a bit of detective work on the abs system since my last post, Ill post the info in case someone might find it usefull
i scoped the output (blue) cable from the front sensor and got a nice square 4v peak to trough signal
i thought that the sensor was giving a 4v output but i was wrong, feeding a 4v square signal from the my signal generator to the ecu wouldnt make the abs light flash
then i noticed the abs ecu outputs 4v which the wheel speed sensor grounds when a tooth passes under it, feed the signal generator output through a switching transistor to sink the output of the ecu and i got my flashing light,
now ive been looking at cherry hall effect sensors online and i think this will work,http://www.alliedelec.com/Images/Products/DataSheets/BM/CHERRY_SWITCH/70207358.pdf

however my background is in radio comms not automation and im not all that familiar with hall sensors, anyone got any suggestions as to whether that cherry unit will work or not?
obviously i will have to fabricate a mounting bracket.

Thanks,
Jim