Reset TPS and Motronic, now starter won't engage

[macx]

Ever have one of those days?

Had been hearing some clattering louder than I thought sounded good so decided to check the
valves - I had set them only 2,000 miles ago.

Also had put in the left side cam chain tensioner, which BTW didn't change the noises any
as far as I could tell.

Found a couple exhausts just slightly loose, carefully adjusted them.

Then thought I'd check the TPS, altho I had checked and set it after a very thorough
tuneup also 2,000 miles ago.

My DVM showed it to be pretty low, was puzzled, but reset it to about 39.
Then reset the Motronic to learn the new TPS setting.

Was going to start it to see how it acted, but then the starter wouldn't engage.
Have lights, ABS power (blinking red light with key on), etc etc.

Checked made sure the kill switch wasn't off.

Then found out my DVM was fubar'd. Bought a new one, made sure the new DVM
zero'd out, rechecked the TPS. Was WAY high - up around 70.

Reset it, again reset the Motronic, still no starter.

NOW what?!

Yeah, been one of "those" days.

Appreciate any help!

EDIT: Just to show you how the day has gone (this wasn't the only battle of the day,
just the last one) - I suddenly realized the bike was still in 6th gear from rolling the
engine over to set the valves.

Voila! Starter engages.

Another "old man" moment. :-/
I guess I was just so used to being frustrated by everything I touched turning to
proverbial poop.

[CycleRob]

macx,

You itemized your start requirement checklist so well, but left off the bright green neutral light before the clutch pull in. Very likely your mind was focused on the complex things for too long causing you to miss the most common simple thing.

The TPS setting I believe I finally used was 370 millivolts. It's something you set once (exactly) and forget it. Finding the zero=zero left butterfly closed, TPS=zero point requires patience and a quality DVM. I pulled the load relief relay to remove the headlight's electrical load so it would not degrade the battery supply voltage, as it alters the TPS reading slightly. Before starting the engine, I set both BBAS (BigBrassAirScrew) to 1.5 turns out, then set the engine idling synch to EQUALITY by adjusting ONLY the right side blue painted idle stop screw. Ignore the idle speed. You're looking for equality only. It's a required setting since you mess up the factory butterfly synch finding the left TB butterfly closing point. That right throttle stop screw adjustment gets both TB butterflys and BBAS at 1.5T perfectly synched . . . a great starting point. Then set the 1,100 RPM idle speed only by adjusting the BBAS. Throttle up to a steady RPM between 3 to 4 thousand to check/reset the on throttle cable synch. You're done.

.

[macx]

Isn't that the truth.

I was really puzzled by the tps setting being I had gone thru the whole
zero-zero thing last summer when I was unable to get my idle down
from about 1400 any other way.

I had a Craftsman DVM but something apparently went very haywire
with it recently, hence the wild goose chase.

Gonna take a trip to get some repair parts for my big mower (one of
the other battles yesterday) and then go thru the TB synch with the
Twinmaster when I get back.

I was a little puzzled when I had the plugs out - also new within about
1,000 miles, oem types - on one side (don't know which side, like top
or bottom or left or right) both plugs had a bright orange/red color on
the center electrode and ceramic.

I'll run it awhile after I synch the TB's and then check them again.

[boxermania]

Assuming both butterflies have not been disturbed from the factory setting or if so, they have been re-set so they have the same opening at rest (many ways to accomplish such but not the topic of the post) the following will apply:

TPS setting at idle is within a range that tells the ECU that the engine is at idle. That range, based on my experience. has been found to be anywhere from 355 mv to 410 mv and the voltage is measured from the rearmost wire on the TPS (#1 on the wiring diagram) the one closest to the rider's leg.

Early on when the "surging issue" first surfaced some of the BMW Techs increased the TPS voltage towards the high end of the range in hopes of mitigating the "surging". In reality the adjustment didn't improve the issues as the range is just a window to tell the ECU that the engine is idling. .

The A/F map is selected by the CCP color or not having a CCP installed, the different colors are defined by the various markets. It is important to know that in the US market the norm is the yellow CCP, however, the absence of such selects a slighter richer A/F map.

That being said it is important to understand hat there are two modes of fuel map operation, usually referred to as open and closed loop operation. The open loop is when the engine is experiencing a load, hard acceleration, uphill operation etc., closed loop is defined by steady state conditions and the O2 sensor comes in play allowing the ECU to lean the mixture so as to improve economy. Under this conditions is when "surging" tends to rear it's ugly head and over the years I have found two items that would affect such the most 1) Too low a speed in a higher gear(lugging the engine) and 2) The general state of engine tune with the following items as primary contributors: TB's sync, leaks between the TBS and the inlet manifold and bad stick coils, if so fitted (the last two items are more prevalent on the older bikes)

Enjoy................

[boxermania]

Apparently you have a 4 plug engine, have you checked the stick coils? Make it a point to look at the plugs and not location when they come out as they wil help you localize any potential problems. How old are the plugs?