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Injectors constantly energised. Cylinders fill with liquid fuel.


Paulsquared

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My injectors energise and stay energised when key on. This results in air throats and cylinders filling with fuel. Also fuel pump has continued to to whir when key off. Any ideas?

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Never heard of this one so have no place to start except square one...no pun intended.

It certainly doesn't sound like an injector issue. I'd begin by pulling the ECU and cleaning the connections. I'd immediately think of a fuel pressure sensor being bad, but an XX doesn't have one, instead relying on the dumb FPR. Hopefully someone smarter than I will chime in. But that's where I'd start. After that, I'd examine the wiring loom issue.

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I should add that I cannot, of course, start the engine because it is hydraulically locked and I have to remove all spark plugs to clear the cylinders.


Thanks rockme... I've checked for corrosion. FPR? Fuel Pressure Relief?? I'm sure that there is a clue in that all the injectors are affected. What do they have in common other than the ECU?

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Wait a minute.

You said the throats (plural) fill with fuel. This led me to believe all four injectors were affected. Is this so?

And secondly, does the fuel pump run as soon as you connect the battery?

Or does it start running when you turn the key on, and not turn off when you turn the key, making it necessary for you to remove the battery lead to stop the pump?

If the pump keeps running, I'd look to your right hand control pod that houses the start button, or to the wiring running to it for a cut or damage. See if you have the same symptoms with the starter pod unplugged. You won't be able to start it, but you don't want to. And get those plugs out and cylinders emptied before there's damage.

Fuel Pressure Regulator....right hand end of the fuel rail.

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Pull the vacuum line off the FPR (fuel pressure regulator) a little metal can on the right end of the fuel rail, and see if fuel comes out of the regulator's fitting where the vacuum line was when you run the pump. It may be that it's blown pumping fuel through the vacuum lines and not the injectors. Knowing whether the injectors are being energized will relate to the cause of the fuel pump running constantly. That aside, I'd squirt some oil into the cylinders before pumping the fuel out to keep things lubed and an oil change will be in order before running it.

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Thanks, Jon. I'm inclined to agree given that all 4 injectors are constantly 'live'. I've had 8 Birds since 97 and never had one problem before this one. It's a 2001 with less than 30k miles. Bummer.

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That's a weird one for sure. I had the hyrdo-locked engine but mine was the regulator that caused mine. I got off lucky as it somehow didn't fill the oil with fuel (a little, but not gallons like some people have had). Pulled the plugs, hit the starter, and watched the geyser go off pushing all that fuel out all over the place.

I have three 99's and there are actually two test connectors; the ground one that everybody knows about by the battery, and a positive version of the same thing on the left side of the frame up by the engine. The dragbike had corrosion in the positive connector that had actually eaten up entire runs of wiring. I don't know if 01's have it or not, but if you haven't done the ground one that could easily be the problem. I'd check the positive one too, especially if the bike stays outside.

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Listen to superhawk996... Don't overlook the simple stuff - the odds are that the FPR diaphragm membrane has been compromised (anecdotal evidence strongly suggests that alcohol blended fuel is not kind to that membrane and over time will take its toll). If that's the case, fuel is leaking through the vacuum/vent tube(s) and into the combustion chambers. That's how the engine will hydro-lock. Liquid fuel won't compress, but it will leak past the piston rings to contaminate the oil. If the vacuum/vent lines are wet with fuel, that's typical evidence of FPR failure.

The good news is that replacing the FPR is easy; it's on the right end of the fuel rail. The bad news, as Furbird referenced, is that your oil is potentially (and most likely) fuel contaminated; fresh oil and a new filter will be in order. Pull the plugs, drain the oil, disconnect the fuel pump connector (2P Brown, under the tank), and spin the engine to pump out any raw fuel from the cylinders. Let everything drain (like overnight). Reassemble with care - don't forget fresh oil/filter.

FWIW... It is very rare, but not impossible, for an ECM to fail - although some aftermarket FI "enhancers" (think like Power Commanders) have presented occasional issues. It's far more likely the FPR is the likely culprit in the case you've described.

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Question: Is there a time/mileage when the FPR should be replaced as a precautionary measure?

I don't think so... It's more or less one of those if it ain't broke - don't fix it scenarios. Mine went bad at five years (very low mileage), so I suspect it's the cumulative exposure to alcohol laced fuels, the ratios of which can be drastically different on a pump by pump and seasonal timing basis (blends differ by location and season - not to mention what's already in the bottom of the storage tank whenever the supply truck arrives).

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Considering that the fuel pump is running constantly and the injectors are held open, the only possible culprit is the ECU or its power/ground connections. Unless something has cut and rewired the bike circuitry, your problem is coming from the control unit. Carefully check all the power and ground connections first, if nothing then most likely your ECU is dead. I'll bet good money it is bad wiring though.

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Listen to superhawk996... Don't overlook the simple stuff - the odds are that the FPR diaphragm membrane has been compromised

+1. KISS all the way. Keep It Simple Stupid. :)

Simply unplug fuel injectors and check whether cylinders still flood with fuel.

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