Mysterious vacuum leak?

[madbrad16]

Sweet! I'm gonna check that out tomorrow. I didn't even think of doing that. I'm gonna try that on the clutch line tomorrow. And then I'm gonna try it on both of the lines where I had my TB sync tool hooked up. Hey thanks man!

[DanV990]

Check the lines going to the stepper motor while you are at it. If you find the problem is with the connections going to the stepper motor and both of the hoses check out you could have a leak in the stepper motor or something blocking one of the valves in the stepper motor or maybe even a faulty stepper itself.

[Galaxian]

don't think so......the ECU looks at the TPS value every time you turn the key on and 'sees' it as zero
try holding the throttle open a bit and hit the starter button.....

new idle speed 3-4,000 right? turn the key off, restart, idle is back to normal
the Aprilia has a real ECU not a Weber-Marelli from 1980

Interesting that. If this is indeed the case, then 'splain me why this function is supported by the Axone on this model if it's done automagically by the ECU. I do likes to learn and all that...

[mini_me]

Afaik a defective one way valve in the slipper clutch vacuum line cant cause any running problems as long as the rubber membrane is ok.

The only ill effect of a non functioning one way valve is that the ppc system isnt able tohold a vacuum thus the slipper function is no longer working.

[DanV990]

Afaik a defective one way valve in the slipper clutch vacuum line cant cause any running problems as long as the rubber membrane is ok.

The only ill effect of a non functioning one way valve is that the ppc system isnt able tohold a vacuum thus the slipper function is no longer working.

If the defect in the one way valve is that it is cracked or the housing is coming apart because the glue went bad like the one described (not the one pictured) in post #4 then surely that could cause a vacuum leak that could cause running problems, wouldn't you agree?

[mini_me]

Yes, I would agree...

Point is that many times I see suggestions being made (all meant well) that a non functioning check valve will cause running problems, that just isnt right.

Talking of the ppc system, if you really want to rule out a vacuum leak in that circuit one could also consider checking for a leak near the shaft of the TB as thus shaft also acts as a valve to release the vacuum created by the ppc system.

[DanV990]

Seeing as the OP has tried two different TB units I think the chance there is a leak at the shaft on both TBs is pretty small.

[madbrad16]

Yah thats actually why I tried the other TB's, to make sure it wasn't a leak at the shaft. And it acted exactly the same with my spare TB's as it did with the originals, so I figured it had to be something else.

[madbrad16]

So i'm working on the bike right now. Both my one way valves are working fine when I test them by blowing through them. Just to double check. Which side is supposed to be on the side of the line closer to the motor? Is it the white or black part of the valve? I'm gonna try hooking up my tb sync tool now and see what happens.

[madbrad16]

AAHHHHHH! This is so frustrating! I just worked on it for a few hours trying everything, but nothing seems to make any difference. Honestly, I don't have time for this and my wife just wants me to sell it. I'm an engineering student that's low on cash and just really need the money. Anybody wanna buy it??

Tomorrow I'm gonna try a few more things and probably call AF1 and see if they have any ideas.

So far, I've switched TB's, airbox's, TB boots, replaced fuel pump lines, removed the PCIII completely, examined and re-examined all vacuum lines and check valves, full tune-up, and probably a lot more that I'm forgetting. It could be something easy and I'm just an idiot. I'm still open for ideas though.

So reading back a lil bit to some of your posts. So whats the verdict on switching different sensors. Do I need to get the ECU redone because the closest dealer with an Axone is like 5 hours away. Could I send my ECU to AF1 and have them do that? Or does it need to be on the bike?

[Galaxian]

For facts related to my earlier statement, I'll refer you to:http://www.apriliaforum.com/forums/s...ating-your-ECU

Scroll down to Amauri's post #6 regarding throttle and idle motor position learning.

[amauri]

Sometimes when you ck and re-ck and replace, adj, etc... you end up getting lost or making things worse.
When that happens to me I put the bike away for a day or two and just start over as if I've never seen the bike before.

Haven't had time to read thru every single post on this thread, but what makes you think you have a vacuum leak at all?

[Micah / AF1 Racing]

Just check the stator leads to see if any are grounded with a multimeter, your problem sounds SO FAMILIAR to what I have seen so many times with a bad stator. While you are there do an a/c voltage check too at idle and 5k rpm.

[madbrad16]

Bike is sold

[BrummyMax]

The difference between the throttle body bores suggests one of the following in ascending order:

1) Clutch diaphragm leak. Is there any oil in the rear throttle body bore?
2) Rear head timing. Lock rear head at TDC and check cam lobe position.
3) Dodgy injector
4) Rear inlet valve problem?

Although Im not that experienced in dignosing these bikes, so someone else might pop up with the answer.