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[spacecadetdave]

My previous post of this subject had me throwing in the towel. Sence then, I continued troubleshooting and replaced the sparkplugs with the Autolite #3923. The bike started right up and ran for about two minutes then quit. I tryed again and again the same results. When it died, I could hear the fuel pump continue running and something under the fuel tank (Montronic Computer ?) trying to program. I felt the TSP and could fill it pausating with the computer. Remember I mentioned the Fuel sensor was not connected to the fuel pump when I purchsed this bike. I connected it and the gauge worked.

My question is what does the Fuel sensor do besides give fuel level indications. and could my Montronic computer be going bad? Any help would be appreciated.

Thank's

[Bprimm]

I still feel the Hall Sensor is the culprit. Changing plugs did not remedy the injectors not supplying fuel.

(previously you said there was no injector spray)

 

Inconsistent electronics is always tougher to pin down then if it would just quit completely....like blow up and then turn polka-dot would be helpful.

[big-t]

Remember I mentioned the Fuel sensor was not connected to the fuel pump when I purchsed this bike. I connected it and the gauge worked.

 

Maybe it was disconnected for a reason...a shot in the dark,but you might want to disconnect it and try to restart.

 

Which connector was disconnected ? I believe all the sensor wires from the fuel tank and the fuel pump are on one connector...if that was disconnected the bike would not run at all

 

 

When computers and electronics start doing things,a good place to start looking would the ground wires,battery ground,and computer grounds,the latter being under the battery box

[EdinLA44]

Have you checked the fuel filter?

[Cali Kid]

Spacedave, Something in your post ain't sounding right.

 

I felt the TSP and could fill it pausating with the computer.

 

TSP= throttle position sensor? If so, I am really curious about that statement. The TPS doesn't move unles the throttle grip is moved, because it moves in conjunction with the throttle valve. If the engine had died, I see no way that the TPS was pausating (did you mean pulsating?).

So double check that.

The other thing you mention is-

I could hear the fuel pump continue running

 

I tend to look for simple answers to complex questions. If the bike dies after short runs, and the pump continues to run after it dies, I'd suggest fuel starvation. Have you had the pump out of the tank and inspected for cracked lines (rubber or metal), looses clamps, clogged filter, or faulty pump? My spidey senses are saying you have a loose line in the tank that is not allowing proper pressure and feed.

[spacecadetdave]

Amen! What gets me, the prevous owner had this bike in the dealer where he purchased it 5 years ago and continued using this same dealer for service. And to find the fuel sensor not connected after the 24000 mile service from this same dealer really makes me causous takening any bike to the dealer. I will remove the tank again and verify all the great information I have been given by this site. This story will continue before I give in to the dealer.

[spacecadetdave]

Thanks for the information. The battery was replaced during the service and I will look into that. I sure hope there is something simple to resolve this frustrating problem.

[big-t]

I will remove the tank again and verify all the great information I have been given by this site.

 

As long as its off,you might as well verify that the fuel pump hoses are still attached and they are on the right connectors.

[Ken H.]

I felt the TSP and could fill it pulsating with the computer.

The TPS (throttle position sensor, large black thing on the outside of the left throttle body) is an input device. It should not do anything physical like pulsating on its own. Are you sure the fuel injectors aren't firing on their own and that is what you are feeling? Which would be symptomatic of a problem that would leave the fuel pump running.

something under the fuel tank (Motronic Computer?)trying to program.

I'm not sure what a computer programing sounds like. Can you describe what you're hearing in more audio terms?

what does the Fuel sensor do besides give fuel level indications.

Nothing.

could my Montronic computer be going bad?

Well I'd like to know these questions first.

[bmwmick]

Dave,

Go back to your original post and read Devid EB Smith's reply. You have a failed HES P/N 12 11 2 306 137.

You have all the classic symptoms.

 

 

Mick

[USAF1]

Try replacing your Motronics relay, under the seat before spending the BIG$$$ for the Hall Sensor......only $8 for the relay.

 

Pat

[Joe Frickin' Friday]

...When it died, I could hear the fuel pump continue running and something under the fuel tank (Montronic Computer ?) trying to program. I felt the TSP and could fill it pausating with the computer.

 

Wish I'd read this thread before now.

 

This really sounds like a Hall sensor failure. I wrote this in another thread:

 

Try this:

 

1. thumb starter and verify that engine will not run (i.e. confirm failure is currently in effect).

 

2. Engage fifth gear, leave key on, and turn rear wheel around. At each compression event (~TDC) AND in between (~BDC), you should hear the fuel pump cycle on for a second or two.

 

If the fuel pump cycles at BDC AND NOT TDC (or vice versa), then it's a Hall sensor problem.

 

If the fuel pump doesn't run at all, then it could be Hall sensor problem or a fuel system problem. Turn the key off/on; if the pump runs at this time, then the fuel system's fine and you have a Hall problem.

 

You can do a final check the sensor itself on the bike with a volt meter. Pull the tupperware, remove the tank; it's a flat rectangular connector, bundled with a clunky round connector (for the O2 sensor) under a heavy vinyl weather hood just forward of the ABS computer on the right side of the bike. You can access the wires from the backside of the connector with your voltmeter probes. Turn the key on, and check pins 2 and 5 for sensor 1 and sensor 2 output (put voltmeter ground probe on battery neg). For each sensor, You should see something like 11 volts for the "high" state, and zero volts for the "low state"; you can check both states by spinning the engine slowly, either with a wrench on the alt belt drive pulley, or with a buddy turning the back wheel.

 

I also wrote this in that same other thread:

 

Do you remember your tach acting funny at all during the problem?

Some failures do this, some don't. Shawn's didn't in May; his HES was just plain kaput, with a pretty steady zero-volt output no matter what. But Rainy's tach went nuts in June. Malfunctioning HES was dithering rapidly between triggered and nontriggered states while at a standstill; Motronic interpreted this as "crank is spinning," and fired fuel and spark (and ran the pump) accordingly, and moved the tach needle around according to whatever RPM it thought it was seeing. A voltage check later showed the HES output on her bike was floating around, drifting up and down across the trigger point.

 

From your other thread:

Yes, I noticed the Tach move up around 3000 then back to 0 momentarily

 

The tach is electrically driven by the Motronic; it moves the tach based on the frequency of the trigger pulses it receives from the Hall sensor. See blue paragraph above.

 

To sum up, withe bike at a standstill, and the engine NOT spinning, you've got:

 

-firing fuel injectors (the pulsating you felt at the TSP, which I think you mean the TPS)

-continuously running fuel pump

-spastic tachometer

 

It sure looks like a bad HES. See top blue paragraph for diagnostic procedure to determine for certain.

 

Remember I mentioned the Fuel sensor was not connected to the fuel pump when I purchsed this bike.

 

 

OK, what exactly was disconnected from what? There is one multi-pin electrical connector on a short cable coming from the fuel tank; this is the connection for the fuel level gage, the low-fuel idiot light sensor, and the fuel pump. If this connector is disconnected, not only will the fuel level gage not work, but the pump won't run (and so neither will the engine).

[spacecadetdave]

To all who particapated with this and my prevous post my hats off to you all who said it was my Hall Sensor. I finally gave in to the shop. I tryed everything mentioned and thought I had it for about 30 minutes then same problem. If I had the proper tools and the wisdom of electronics, I would have challagened this feat. Again, thanks to this site. And next time I'll lesson the first time.

[Bprimm]

Mitch..you can see his earlier thread here for the same question.

 

He started a new thread whithout a link to his previous.