Gen II sputter, jolt, choke, and stall (with video)

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southbayninja

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Hi all

Had a strange and concerning fault recently, which I have not been able to replicate on demand. It seems to be almost at random. When riding, the engine will suddenly start to choke, causing the bike to jolt violently. My only remedy is to pull the clutch, after which the bike will sometimes stall. If I rev and change gear, the bike settles for a few seconds before sometimes repeating the glitch, sometimes continuing normally. This can repeat for as long as 30 minutes or as little as 10 seconds, and there is no advance warning. It often happens when accelerating, but not always, sometimes I'm just cruising and the engine will suddenly start to jerk and jolt. If it were to happen in a sharp corner it could easily cause an accident. There is no smell or strange sound coming from the engine or bike, that I can tell.

One interesting check I did was to rev the bike and hold the throttle steady. I noticed the revs would slowly dip whilst I was holding the throttle in the same position. I did this whilst the engine was fully warmed up after a ride, and I checked the TPS in diagnostic mode, all was fine. However, I did have the following stored code: "14 - intake air pressure sensor hose line".

I took this video - you can hear where the bike struggles and I have to rev through it. You can also hear what sounds like an grumbling engine at times but that noise isn't obvious to the naked ear when riding: https://youtu.be/RhD_dK_JefI


This does seems to be related to colder than usual ambient temp (55-70), and occurs across a range of engine temps (160-180), and across the entire rev range and in all gears. As far as I'm aware, the only thing that's change on the bike recently is the battery, though this was also happening before changing the battery (accidentally left the power on and drained the battery). Both the old and new batteries lived on a trickle charger every weekend. Before this started to happen, the bike was running beautifully. I am running a PCIII and FCE, though I've never fiddled with either one, they were installed when I bought the bike.

This problem is causing me to lose confidence in the bike and my confidence on the road. I love this bike and am desperate to get it running smoothly again. I have an initial suspect of the cause but would appreciate any and all input.

Thanks in advance.
 
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Wow doesn't sound good at all. Well I would start with sorting out the error code 14. If thats not it then look at fueling, then coils and plugs? Could try unplugging the pc3 put it back to stock to see if anything changes. Process of elimination
 
If this we me I would start with the fuel line. The stock ones tend to kink and can cause symptoms like this, search for the fiel line mod on here and switch it out. If the old one is kinked up id say you found the propblem. If it happens again after that i would disconnect the FCE. Many people have had problems with this device, myself included. Love Ivans products, im running his flash after having too many problems with the FCE. Fact is it can fail, and can cause similar problems. No way to diagnose it except pull it and see if it stops the problem. Because it is an electical component and you yourself did not install it their is a higher probability of it being the problem. Good luck sir, im confidant you can diagnose and fix this and get back to full confidence in the old fizzy.

Edit: search here and on the other fz1 forum for "damn surging continues" read a bit and see if this is similar to your experience. If so id say it's the FCE, it's the one common denominator among every post there. However i would go ahead and do the fuel line mod while under there, its a cheap easy mod that yamaha r&d should have fixed in the first place.
 
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Thanks - my first suspects were the FCE or the fuel line. When I lifted the tank I noticed the air box intake hose was loose. I reattached and tightened the clamp, seems to be OK so far.

I am tempted to the fuel line mod, especially as my tank won't lift all that much. It's difficult to tell which line is causing the restriction. Has anyone any experience with a tank that won't lift up that much, or in creating more slack but not causing a kink when setting it down?
 
You did take the seat off before lifting didn't you? you should be able to lift it up over 45 degrees, but that is about it without removing lines or rear bolt.
 
1st thing I would do is check all the connections to the FCE. I had a similar experience once. Or remove it all together and see if the issue resolves. You REALLY want it flashed anyway. It's so much better.
 
Yes the seat was off when lifting the tank, got maybe 30 degrees or so before the hoses started tuggging. Very difficult to access the air box with that little clearance.

When referring to 'flash' is that a reflash of the PCIII, or the ECU? In either case does that allow for the FCE to be removed?
 
Sounds like something is too short under there.

Flashing the ECU will allow the FCE to be tossed in the bin. You then use a PCIII or PCV to map the air:fuel ratio if you use an Ivan Flash, or VCyclenut has a map he puts into the ECU. I prefer a map suited to my bike so I run a PCV with Ivan's flash.
 
southbayninja said:
Yes the seat was off when lifting the tank, got maybe 30 degrees or so before the hoses started tuggging. Very difficult to access the air box with that little clearance.

When referring to 'flash' is that a reflash of the PCIII, or the ECU? In either case does that allow for the FCE to be removed?
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Thats about as far as the stock fuel line will allow, disconnect it from the bottom of the tank to raise it further. Def do the fuel
Lime mod, it will allow easier access to the airbox and fce. Ivans reflash is of the ECU and it eliminates the need/use of the FCE. I'd bet a testical its one of these two issues or a combination of both fuel lineand FCE.
 
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