Injectors not injecting.

I need help please. I've finally given up.

Preamble: 1150gs non abs single spark. I took it off the road last Autumn on return from the Alps where I'd developed a final drive oil leak. The "repair" developed into a bit of a refurb .....badly blistered paintwork on the wheel hubs, swing arm, everything really. Powder coated rear subframe and various other bits. Replaced front and rear shocks and generally a good cosmetic fettle.

Fast forward to "lockdown" , everything tidied up and back together . Started her up she ran for a minute or so then gurgled, misfired and cut out. Further attempts to start failed . Nothing , not one bang.

After much reading in this Section and other places I've still failed.

To date: Fuel pump primes. Injectors won't operate. Tried Steptoe's test. Light bulb doesn't light. Tested Halle sensor with LED lamp/bulb and that works fine. Getting sparks ok. Turned engine over with injectors out and nothing.

Connected each injector to a small battery off the bike and they open. Injectors cleaned. No fuses blown.

By now I would have given up and trailered it to Mikeyboy but some cnut ran into the back of of my van bending the tow bar, so I'm fukked for taking it anywhere.

Am I missing something obvious ( highly likely as I've only been "messing" with bikes for 50 years) or is there someone in/near Sheffield who could come visit and show me the way?

Thanks in advance.

Not sure how you checked the injectors but I had a similar problem years ago and it was down to an internal wiring fault. I fixed it but bought a spare connector and you can have it if you want. Might not be the answer but maybe worth a try?

Have you had the tank off ? This caught me out, the fuel line QD wasn’t full seated home. Just a thought.

Oldie said:

Not sure how you checked the injectors but I had a similar problem years ago and it was down to an internal wiring fault. I fixed it but bought a spare connector and you can have it if you want. Might not be the answer but maybe worth a try?

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Checked injectors as per Steptoe's instructions. No flickering /flashing bulb when engine spun.

alanbmwgs said:

Have you had the tank off ? This caught me out, the fuel line QD wasn’t full seated home. Just a thought.

Click to expand...

Had tank on and off a few times . Fuel lines pressurised up to the injectors.

Have you checked inhibit switches are working correctly?

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What about the big connector thats on side of LHS injector - has the clip been clipped up and all connected together right.
Good luck

MickDB1 said:

What about the big connector thats on side of LHS injector - has the clip been clipped up and all connected together right.
Good luck

Click to expand...

Yes all ok there Mick. Never had it off.

topcat2006 said:

Have you checked inhibit switches are working correctly?

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Click to expand...

Enlighten me please. What are they?

Kill switch.
Sidestand switch.
Clutch switch?
Neutral switch.


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Are you getting power to the injectors.?

When the fuel pump primes. That brief period applies power to the fuel pump and the injectors. They share the same power feed. Once the engine rotates, The fuel pump relay provides power to the pump and injectors and the motronic provides negative pulses to the injectors to allow them to open. With the injectors not operating one or both the voltages are missing.

First off, give a gentle push to each of the contacts in the injector plug, just to make sure they are all locked in position. If they’re not locked, then when you fit the connector to the injector the contacts will get pushed back and not give proper contact. Unlikely but you never know.

I would connect a voltmeter between each of the two injector green/white wires and a good ground and check you get that momentary 12volts when the fuel pump primes. All being well you should. Now if you don’t then it could be you have either a break in the wiring somewhere or a corroded joint. One place worth checking is the tank breather connector which is not used, and tucked under the right hand side top frame tube under the passenger seat. It could have chaffed through coursing a high resistance to ground dragging the voltage to your injectors down. It’s a long shot, and should blow the fuse, but with old wiring and natural corrosion, all sorts of resistances build up, and the current might not be high enough to blow the fuse.

Now if you are getting that magic 12v, then the fault could lie with the motronic signal on the yellow/grey wire. This is the switched negative, and feeds the injectors to open them, and is also fed to the diagnostic connector. So you should be able to continuity test that line from each injector to the diagnostic connector pin 10.

Some or all of this you may well have covered. My apologies if so.

Ian

As it looks highly likely that you have a wiring fault, it might be worth doing some continuity checks.

Pin 1 of the injectors, Pin 2 of the fuel pump, Pin 1 of the tank breather valve (Not used, tucked under rear seat) and the output of the fuel pump relay are all connected electrically. So just measuring the resistance between these points might help track down a wire break.

If you’re not familiar with continuity testing, it’s just measuring the resistance between two points ensuring power is off. Ideally the resistance should be zero.

Thanks very much Ian. Will give that a go when I get chance.