Replaced IACV, but...

[haroldo_psf]

Hi all.

I am a new owner of a 2000 855i with 50K miles. As posted previously on other threads, the bike has a stalling issue, which happens during idling, specially if I blip the thottle, or if pulling the clutch and chopping the throttle suddenly, causing a sudden drop in rpm.
When idling, it's lumpy around 1K rpm. It sounds like it  misses its rithym once in a while, sounds weak whily idling, and it has stalled while idling before.

This is the sequence of events, which confuse me a little:

1) When I first got the bike, I filled the tank, and poured a whole can of SeaFoam in (injector cleaner, octane booster, fuel stabilizer). It made no difference in the way the bike ran.

2) When I had 1/4 of a tank left, I took the tank off, and replaced the IACV. Took it for a ride, it  ran GREAT. The rpms held steady at  around 1100 while idling. I could NOT make it stall. I would try hard to do the things that caused it to stall before, and it would not stall. I was so proud of myself :)

3) The fuel light came on. I was running out of fuel, having too much fun. I stopped and fueled the tank. As I turned it on, I could tell right away that the crappy idling was back (maybe worse than before, but  it might bein my mind), and it was stalling again, just like before.

WTH?

I do have the surge while holding steady thottle, and I have all the symptoms I 've read about here on throttle position sensor issues (TPS). This is the next thing I will replace. Could this be a contributor to the issue? For example, the sensor doesn't output the correct voltage for closed throttle, and the ECU doesn't apply the correct idle fuel mixture, causing a lean condition?

It sounds like I'm too lean while idling (Agree?). Could a vacuum leak cause it?  I looked at the hoses going to the IAVC, and they are plastic hoses, were dirty, but didn't look or feel cracked.

Is there any possibility that a crankshaft sensor might  be also a contributor to this condition?

What is that gasket that some people find it missing? Something around the air box or throttle body?

Wild guess here, but since it happened right after I put new fuel in and diluted the injector cleaner/octane booster in there, I will try to put some in there again and see if it  makes a difference.

Thanks in advace for any suggestions.

[walker]

fuel filter changed? Fuel fittings not leaking? All hoses to the tank are in place? Air filter changed?

[haroldo_psf]

Hi, thanks for the reply. Yes, it has a new fuel filter, new K&N air filter, valves checked and TB sync'ed 8,000 miles ago, all hoses are in place. I have the metal fuel fittings.

I do have an aftermarket slip on (OEM Triumph). I wonder if I need a new map? I wouldn't think so, since it has a closed loop FI system with an O2 sensor. Speaking of O2 sensor, are those known to go bad and need replacing? Could it be part of the problem?

[haroldo_psf]

Holy crap! I just did a 12 minutes tune, and the bike is running like a champ! The rpms hold steady at 1K, and it is not nearly as lumpy as before.

I rode it for 35 minutes, including one or two stops where I turned off the key, and then came to work. It never died on my once, not once.

Am I dreaming???? I am now scared to go fuel it up and have the symptoms come back.

Is there really a chance that this did it, in combination with replacing the IACV?

Or maybe there is really a faulty sensor somewhere (crankshaft, TPS, etc) which the ECU will learn soon and the bike will run crappy again?

[walker]

always a good thing to reset the sensors if you replace something. Just ride it - if it comes back, then worry. Till then, you're good!