1999 X1 won’t idle

Hey all. I’ve searched other posts, nothing specific to fixing it, other than reset TPS (which was the first thing I did).

Bike will start, then immediately dies. I watch TPS voltage on ECMdroid, see that it tries to open the throttle to maintain, but can’t meet the need and dies. Subsequent attempts to start while opening throttle manually and the bike burps and backfires thru the air filter.

All else appears good to go. No codes on ECM spy pop up. Changes to new plugs and checked wires, no issue I can see. Maybe starved for air?

Any thoughts would be greatly appreciated!

Blindly guessing will cost you frustration, time and money:upset: Wouldn't you rather be out riding?
RTFM: https://www.buellmods.com
Diagnosis is at 1-42

The TPS (Throttle Position Sensor) is only a sensor, it does not actuate the throttle. Pressing the button to reset the TPS without the correct procedure will cause exactly your problem so now you need to UN-do what you did before you can start to repair your bike.

TPS re-set procedure at 4-100, Idle setting at 1-36 and 4-40.

All that said, once you perform that procedure correctly, I doubt it could be a TPS issue at all. Start with the simple stuff that the manual says. Pull the plugs, LOOK at them, clean them well or replace them.

Plugs diagnosis at 1-33

That should get you going in the right direction:eagerness:

Most of that has already been done.

TPS was reset IAW the procedure, new plugs (already had some on hand) at proper gap installed, wires appeared to be fine.

As far as setting idle, can’t get it to idle in order to further adjust the idle screw for the proper setting. Again, currently sitting at the setting called out in the TPS reset procedure (5.8).

Need to clean out the throttlebody a little still. Checked fuel pressure, good to go. Can try to check for air leaks as well.

Again, it starts, then just dies.

Quote:

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Originally Posted by Salvooch

Most of that has already been done.

TPS was reset IAW the procedure, new plugs (already had some on hand) at proper gap installed, wires appeared to be fine.

As far as setting idle, can’t get it to idle in order to further adjust the idle screw for the proper setting. Again, currently sitting at the setting called out in the TPS reset procedure (5.8).

Need to clean out the throttlebody a little still. Checked fuel pressure, good to go. Can try to check for air leaks as well.

Again, it starts, then just dies.

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If you are going to pull the TB for cleaning, you may as well change the intake seals while you are at it. With the TB out of the way, its easy on a tuber.

Still no joy... I’m thinking it’s a sensor telling the bike to just quit shortly after starting (as in 2 seconds...).

Is there a way to mask sensors in ECM droid? As in, hide the BAS result so any kill signal from a bad sensor is masked... I see something that I think is it, but don’t know if checking the boxes hides the sensor, or if leaving unchecked hides the sensor... or if I’m even in the right part of the app.

It's sort of counter-intuitive but checking the box in the "error mask" section allows the ECM to light the CEL for that sensor circuit. So IMO, check them all.
An unchecked box means the ECM will not light the CEL if it sees a reading outside normal on that circuit.
No, there is no way to run the bike without all the sensors operating and your BAS is not causing that problem, easy to check, procedure is still in the RTF service manual:
Buellmods.com

If you are determined to repair it yourself, take a hint from Robert Pirsig:
"When your answer to a test is indeterminate it means one of two things: that your test procedures aren't doing what you think they are or that your understanding of the context of the question needs to be enlarged. Check your tests and restudy the question."

Highlights by me.

Don't worry about ECM programming yet. Look at the basics. You don't even know if it's electrical or fuel related.
Spray some starting fluid (NOT carb cleaner) in the TB while trying to start it. If you can you get it to keep running, the issue is fuel related... while the starting fluid is also cleaning the new plugs if they are fouled. Even though you

Quote:

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Originally Posted by Salvooch

Checked fuel pressure, good to go.

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there could be a fuel volume issue from a clog or weak injectors.

Next you can use a simple spark tester to see if the plugs quit firing before the engine dies, then work back through that system if they do. Coil power could be getting cut by being on the wrong circuit, etc.