| Author |
Message |
    
Deadprez08
| | Posted on Sunday, August 26, 2007 - 01:25 am: | 
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So I'm unsure as to the cause or definite beginning of this but--
When I downshift I revmatch and sometimes when I blip the throttle going into 1st it sounds like air is blowing directly back through my intake and makes a POP noise (like a biiig bubble bursting).
What could possibly cause a symptom like this and how do I resolve it? |
Rob04xb12
| | Posted on Sunday, September 02, 2007 - 04:49 pm: |
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I dont know what it is, but my bike does it only really when its switching from open to closed loop after a cold startup
It will do it a few times over the course of a few minutes then it stops
I would like to know why it does it too |
Grianp
| | Posted on Monday, September 24, 2007 - 12:25 pm: |
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my 2005 xb9sx does the same thing. ever since i installed the full race kit and had my tps reset, it will do it occasionally when rev matching on downshifts. i have had it happen down shifting into third, second, and first. first gear is when it occurs most frequently. Does anyone know what causes this issue? |
Sparky
| | Posted on Monday, September 24, 2007 - 08:19 pm: |
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Assuming everything mechanical is OK in the engine (intake manifold seals, injector O-rings, exhaust gaskets, exhaust pipe to collector sealed), the TPS and its calibrated zero point is the key for telling the ECM how much gas to squirt when rapidly opening the throttle for downshifting. It tracks the rate of throttle opening and adjusts the fuel injector pulses accordingly to give an extra rich shot of gas just like an accelerator pump would for a carb.
Now, if the TPS does not have a quite accurate enough reset job, the ECM might be off by a little bit in gauging how much extra gas to give in these situations. So, I don't know, maybe the bike needs another TPS reset job done reeaally carefully?
Or there might be a slight intake leak somewhere; there is a rubber plug on a vacuum fitting on non-California models that could be cracked, letting air in. It might be worthwhile to check that out. |
Deadprez08
| | Posted on Sunday, September 30, 2007 - 12:17 pm: |
|
The TPS seems most suspect, given those considerations.
A slightly different symptom has come up lately- if I've not been pushing it too hard, matching down to first sometimes makes the pop, then opening the throttle again kinda gives off a big gurgle; the same "backwashing" sound, but repeated, as if the engine is about to die on me.
That narrow possible causes any or is that by the same things?
Thanks for the response Sparky |
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Intake pop on 03 XB9s