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Discussion Starter · #1 ·
I did the inline fuel filter mod, recently, and now I can't start the bike, fuel doesn't seem to be getting to the cylinders.
Today I lifted the tank up, and unclipped the fuel hose where it attaches to the injector system- and there was so much stored up fuel pressure that it dramatically sprayed out in my face and all around. After the initial surprise and shame of it all, I am left wondering what the hell is going on.
The fuel pump primes, but halfway through starts to strain. How does the fuel system work, does it draw fuel into the system, then return it via the return hose? If that was somehow blocked would that cause my woes?
 

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Sounds like it's not getting through the filter.

You took the dust bungs out of the ends of the new filter before putting the lines on it? (Not all filters have them some do).

Easy check - remove the return line from the fuel rail regualtor to the tank (there is a rubber bung in the storage tray of the TLR to block the tank nipple to stop the fuel from leaking out - on the TLS the bung is on the end of the tank prop rod).

Turn the ignition on and make sure there is fuel coming out of the rail return line.

But if the pump is priming and battles as pressure rises, I'm thinking blockage. Probably the new filter.

(Although I thought I read in another thread of yours on the same problem that you initially heard bubbles in the tank?)

If the return line was blocked I would think it would still start but run rich due to the excess pressure in the rail. Have ou looked down the TB's to see if fuel is spraying? No FI codes after 6 or more seconds of continuous cranking?
 

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Discussion Starter · #3 ·
when I filled the tank again after taking out the filter I heard bubbles as it started to prime, which I assumed was fuel displacing the air that was in the pump mechanism that got in while it was outside of the tank.
I think the filter is not blocked, the end of the hose I detached was after the filter, so I assume that if there is pressure up to that point then any blockage would be after that point. The tank sat in my garage for about three years, it might be that the tubes for the fuel return are blocked, I could test the fuel return hose by unplugging it then priming the fuel, though how would I check the fuel return pipe within the tank?
I stink of petrol!
 

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Discussion Starter · #4 ·
I forgot to mention that after priming the display flashes FI for a few seconds, then the normal display, the FI and so on. No codes in dealer mode, but then again I don't crank it. My bike has a habit of accumulating fuel in the headers when it doesn't start, and after a few seconds it explodes, and I don't know if my old carbon pipes can handle that anymore.
 

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If the dash is flashing FI then there is something wrong. You need to leave it in dealer mode. (When there is a fault FI is flashed up, not held there permanently).

If you remove the return line to check for flow, you'll know if the tank is blocked or not depending if fuel pisses out of the tank.

You didn't disturb the cam sensor or cam sensor wires with the installation of the new line? How about the TOS? Is that ok?
 

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Discussion Starter · #6 ·
I detached the return line- fuel pissed out all over me again, and on the engine, but that is one less cause.
When I primed the pump, fuel slowly came out of the return hose, I don't know how fast it would usually come out, but it was little more than a dribble. After a few primes the pump started labouring again, FI flashing all the while.

I don't think I knocked any wires loose, as for the TOS (tip over sensor?) I have no idea where that is.

I changed the filter after the bike stalled, then only ran on one cylinder. I had assumed it had to do with fuel pressure. When you disconnect the fuel line, is it usual to have so much pressure that it sprays out dramatically? In the past it has more just leaked out than flew out when I disconnected it.
Would air trapped in the filter due to its orientation, compressed by the fuel pump, explain this spray?
 

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Check your spark plugs.

Put it into dealer mode, leave it there and read off the code that is thrown.
 

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Discussion Starter · #8 ·
the plugs were pretty blackened, what was strange is that they were not wet after I tried cranking it.
How long do you need to crank it to get the FI codes to come in dealer mode?
 

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6 seconds or so will do it if it's a crank or cam sensor problem. Other faults will appear in the dash as soon as the ECU knows it.

Change the plugs for NEW ones. If they're darkened and you had on cylinder firing and now none, just change them.
 

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When you disconnect the fuel line, is it usual to have so much pressure that it sprays out dramatically? In the past it has more just leaked out than flew out when I disconnected it.
Yes, whenever you detach the fuel supply line without first letting the injectors + return line "leakage"
"bleed down" the pressure, it sprays for a second or two. This depends on the
amount of fuel in the tank; since the return line is at the back of the tank, and
its hinged, when you tilt it up with a lot of fuel, the return line sees a lot of
"pressure" from the depth of fuel in the tank.

This pressure sets the "zero reference" for the regulator, against which the pump
supplies 45-70 psi "rail pressure" -- in almost every present day EFI system.
45 psi is about the same pressure as your average kitchen sprayer head.
So, depending on how much fuel is "in the rail" it can spurt pretty hard.

By adding the fuel filter in the return line you've added a little "reference pressure" to that line,
which further raises the enrichment that the injectors will see -- a tiny bit higher pressure,
therefore a tiny bit richer. Not enough enrichment to be concerned about, normally.

It does sound like you have an injector leaking,
since you're accumulating fuel at startup. One failure mode for injectors is
that they tend to 'drool' at shutoff, slowly bleeding down the 45 psi in the rail,
and any return line fuel that works its way backwards of the regulator's check valve.

hth.

--frankb
 

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Discussion Starter · #11 ·
Thanks for the help and info, it's made it easier to diagnose the problem.
I cranked it, then checked the plugs, and the rear plug was wet, but the front one was not, so it looks like something is wrong with the front injector.
Does anyone have an idea about how I could fix it? If I get a mechanic to have try to fix it, will I have to take the bike in, or can I remove the entire injector system from the bike?
The FI code that was flashing was coming because I had unplugged the temp sensor on the radiator so I could swing it forward to take out the front spark plug. I'm glad it was just my idiocy, rather than a real problem.
 

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Change the plugs!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

do nothing else till you've tried NEW PLUGS!!!!!!!!!!!!!!!!
 

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:stupid

Change the spark plugs & try again.

IF you still have a problem with the front you can try swapping the primary and secondary injector plugs over so it runs on the secondary injector. That will help confirm if you do have a fault with the injector or not.

Charge the battery, change the plugs and all will probably be ok.
 

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Discussion Starter · #14 ·
I will change the plugs tomorrow, nothing is open on Sunday so I couldn't get new ones today.
I find it strange that the front plug was dry, but the rear one was wet after cranking it (Plus when it died suddenly it felt like it was running on only one cylinder, though wasn't backfiring from unburnt fuel going into the exhaust, which lead me to believe fuel wasn't getting to one of the injectors.)
I've taken the injectors out, and will swap them around when I put in the new plugs tomorrow, I assume they are the same and that swapping won't cause a problem.
No fault codes when I crank it, by the way. Once or twice leading up to it dying I got a fault as I was riding, but it went away when I stopped to check it out. I really hope it isn't something other than a fuelling issue.
 

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The 4 injectors are the same :yes

(Should look at getting them professionally cleaned and flow rate tested while you have them out)
 

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Discussion Starter · #16 ·
I'll see about getting them cleaned. Can a car mechanic check them? I'm hoping after the new filter (the old one was clogged with rust particles) and an injector clean that the bike will run a lot better- if I get it running that is.
Thanks for the help, it is greatly appreciated!
 

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Discussion Starter · #17 ·
Changed the plugs- runs perfectly. Doh!
In case anyone finds it relevant, the front cylinder will sometimes be dry while the rear cylinder will be wet after cranking, which is apparently a normal situation. A bloke I called about fuel injection cleaning said that the rear cylinder runs richer to compensate for differences in heat of the two cylinders.
My mistake was assuming that having a dry front plug meant that my fuel system was not running properly. I hope others can learn from my mistake.
 

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The rear has different fueling and ignition maps if the manual is to be believed ;)
 

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Or more likely only the rear plug was completely fouled, and the front one was firing enough to and stay clean, if not enough to run.
 
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