Still won't start... Mk2

Mac Henderson

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I was following the recent thread closely as my 2003 twin spark also won't start; as Rob seems to have left us in the lurch, I'd be really grateful for any help.

A little background...
I recently did a slow speed riding course which was really enjoyable until I stalled it (3 times!) on the tight section of the "advanced" obstacle course. No problem, its a BMW and instantly restarted.. twice. The battery was soft anyway and had been on charge the night before, so thinking the morning's efforts had proved too much for it, we clamped on the jump leads and hit the starter button at which point the starter motor started smoking. Trailered bike back home and removed the starter, then stripped and refurbed using the excellent Mike P thread. As per the thread, the grease retention plate in the starter had worked loose and shorted out, but luckily wasn't holed, so I cleaned up all the parts, lubricated everything, rebuilt it and bench tested it to confirm all was OK. One rebuilt and lubricated starter re-fitted, hit the button and the engine turns over faster than before but doesn't even try to fire.

As above, the bike is a 2003 Twin spark.

Refering to Steptoe's advice:
I've pulled the fuel pipe from the injector and can confirm I DO have a fuel supply.
I've also pulled the electrical connector from the injector and can confirm I DO NOT have a signal at the injector.
I also have NO SPARK at the plugs.

All fuses are OK.
All relays are OK.
I fitted a new Motobatt battery before refitting the starter motor.
There are no loose plugs or connectors.
Everything else still works, lights, horn etc.

I also found another thread which recommended removing fuse 5 for 10 minutes then going through the throttle/TPS routine to reset the Motronic. This made no difference and it still won't start.

The bike was running really sweetly until this sudden stop. As I've lost both electrical signals to the plugs and the injectors, I'm currently thinking along the lines that the multiple stalls were enough to shake the grease retention plate loose, causing the short. Then the high current draw when the jump leads were attached has FUBARed something else. HES? Motronic? This is hopefully just my paranoia and somebody can can set me right?

Any assistance would be very much appreciated and I promise not to leave people hanging once the solution is identified!

Thanks in advance,

Mac
 
Hi Ian, thanks for a speedy reply.
Yes, the pump cycles.
Ignition on, and all the normal noises as the pump cycles and pressurises the fuel line. Fuel pumped into the jar when I disconnected the line, so I have fuel, but its not getting into the cylinder as no injector signal. Also confirmed by the complete lack of any fuel smell from the exhaust.
I wondered about the HES as its seems like the Motronic doesn't know the engine is turning, hence no injector signal or spark, but I'd like to get a diagnosis based on an analytical basis and the collective wisdom before I start spending money and changing components which could be OK. I also remember from the earlier thread that Rob had changed the HES and no result.
 
Hi Ian, thanks for a speedy reply.
Yes, the pump cycles.
Ignition on, and all the normal noises as the pump cycles and pressurises the fuel line. Fuel pumped into the jar when I disconnected the line, so I have fuel, but its not getting into the cylinder as no injector signal. Also confirmed by the complete lack of any fuel smell from the exhaust.
I wondered about the HES as its seems like the Motronic doesn't know the engine is turning, hence no injector signal or spark, but I'd like to get a diagnosis based on an analytical basis and the collective wisdom before I start spending money and changing components which could be OK. I also remember from the earlier thread that Rob had changed the HES and no result.

Maybe you should post the link to robs thread, so we are not going over the same things that you have already tried,

There is a way to test the HES, using a diode, it’s rare that they don’t work at all though, usually intermittent.

It’s so hard to diagnose stuff over the Internet, you need to find out if it’s getting a signal from the HES, then if a signal is coming out of the ECU, and if the coils are being switched, as both the injectors and coils are not working, it would tend to point to the HES or wiring to the ECU, or something like a tip over switch.
 
Thinking about it, the pump should continue to cycle as the engine turns, have you took out the plugs, and turned the engine by back wheel, to seeing the pump recycles, the HES plate has two sensors, I suspect one works the pump, the other the ignition, but ignition won’t work if the pump HES isn’t giving a signal, as the engine will need to be spinning at a minimum rpm,

You can test the HES using a 12v led, to be fair it’s 15 years old, they do go, it’s just a matter of time, replacing it is not a waste of money,

Otherwise search for the instructions on how to test it, it’s the first thing to test.
 
Im with Ian and suspect HES, however if it was me I would take the tank back off and carefully inspect every inch of the wiring harness for signs of burning/bubbling before buying replacement parts.

Does literally everything else electrical on the bike still work, all lights, RID (fuel, gear, time)?
 
Thinking about it, the pump should continue to cycle as the engine turns, have you took out the plugs, and turned the engine by back wheel, to seeing the pump recycles, the HES plate has two sensors, I suspect one works the pump, the other the ignition, but ignition won’t work if the pump HES isn’t giving a signal, as the engine will need to be spinning at a minimum rpm,

You can test the HES using a 12v led, to be fair it’s 15 years old, they do go, it’s just a matter of time, replacing it is not a waste of money,

Otherwise search for the instructions on how to test it, it’s the first thing to test.
Remove plugs and turn engine over in gear with the rear wheel,the fuel pump should cycle every turn of the engine
 
Thanks for the replies so far, looks like tomorrow will be a busy night in the shed.
To answer Gog's question, yes, everything else seems to work: lights, horn, RID, fuel, dash lights, spot lights. Only thing that doesn't work is the engine! The tank is already off and I was inspecting the wiring last night. There is some heat damage on the outside of the loom covering that goes to the Motronic, but it old because its covered in the under-tank dust and grime to be certain, I made a small scalpel incision in the cover and peeled it back to find all the wires (and insulation) undamaged and intact. Looking ta the ham fisted installatrion of the spotlights and associated relays and wiring, I suspect somebody before me was little ham fisted with the soldering iron.

Ian/Mikey: Thanks for the details, I'll pull the plugs tomorrow and report back.

Unrelated feedback for Mikey: you rebuilt my FD 2 years ago and I opted for the pivot bushings over the OE tapered bearings, 2 years on they're still fine with no discernable play and haven't needed adjusting. There, thats the kiss of death for them, then!
 
Being honest of your battery was bad and not getting a recharge before the next start

Its likely that it is the HES

The current surges and voltage spikes as you try to turn it over with a duff battery are horrendous

My Foreman at BMW told me if I ever went to start a bike with a bad battery NOT to grind it over but to release the starter button ASAP and change the battery or "at least" check the electolyte levels and recharge it before you go near trying to start it again

Whilst the ECU is protected by solid state components the HES is not and is susceptible to damage
 
I dont know much about oilheads,

But thinking about Injectory stuff.

Does the bike have Cam or crank sensors?

failure of one or the other will confuse the hell out of the iginion system .
 
Remove plugs and turn engine over in gear with the rear wheel,the fuel pump should cycle every turn of the engine

One problem with this test, it's inconclusive ......
If the fuel pump DOESN'T prime then it's almost certainly the hall sensor...

But if the fuel pump DOES prime the hall sensor can still be the problem. :D
 
One problem with this test, it's inconclusive ......
If the fuel pump DOESN'T prime then it's almost certainly the hall sensor...

But if the fuel pump DOES prime the hall sensor can still be the problem. :D

It’s always worth testing, even if the test proves inconclusive. though you could argue that replacing it, will either fix it, or avert a breakdown sometime in the future, it possibly being 15 years old, with a known history of failing.
 
Yes they are called Hall effect sensors and there are two on the front cover, and the timing disc is on the crank nose

Dont know whether it will work , but when i had similar type failure on a car i had. Unplugging and replugging the cam sensor back in

would give the sensor a kick which was enough to allow starting , Once running all was good until i stopped again
 
Afternoon all,
Thanks for the help so far. Unfortunately life is getting in the way; end of school term stuff plus having to work for a living means I won't now get to this until the weekend, but I will follow up your suggestions and keep you posted.

Cheers,

Mac
 
Fuel pump priming when switching ignition 'on' is a function of the Moronic.
Fuel pump priming when cranking the engine via the rear wheel is a function of the HES.

Paul.
 
Hi Ian, thanks for a speedy reply.
Yes, the pump cycles.
Ignition on, and all the normal noises as the pump cycles and pressurises the fuel line. Fuel pumped into the jar when I disconnected the line, so I have fuel, but its not getting into the cylinder as no injector signal. Also confirmed by the complete lack of any fuel smell from the exhaust.
I wondered about the HES as its seems like the Motronic doesn't know the engine is turning, hence no injector signal or spark, but I'd like to get a diagnosis based on an analytical basis and the collective wisdom before I start spending money and changing components which could be OK. I also remember from the earlier thread that Rob had changed the HES and no result.

Your fuel test at the injector is inconclusive. The problem is that a split in-tank hose will still allow fuel to be pumped to the injectors at low pressure. A conclusive test is to leave all injectors attached, disconnect the return line at the QD, press open the check valve on the side COMING FROM THE PRESSURE REGULATOR, and switch the key on. You should have a strong flow of fuel.

This test pressurizes the injection side of the system and shows that the pump/hoses can build the pressure needed to open the fuel pressure regulator.
 
Good evening all and welcome to the latest instalment.

So I followed Mikey's instructions, pulled the plugs, into gear, ignition on, turned the wheel and the pump primes at each rotation of the engine. Also checked the relevant pins in the tank connector and got a good 12V-0V signal with each rotation, so it seems the fuel pump side of the HES is working OK.
Also checked the side stand switch and bridging the relevant pins gives a good on/off signal, so that seems OK too.
I then decided to check the spark again and found I had an intermittent spark; compared to the previous no spark, this was an improvement but it still wouldn't start. A quick shot of Easy Start up the snorkel and it fired up immediately. Wild rejoicing.
Put the tank on and connected up the fuel and she started up first go and settled to a steady idle. Next thing is to see if she starts in the morning.......

Going back to Ian's post #4, I note he says that the HES usually fails intermittently, so I suspect this is the fault and presume that the high current draw from the shorted starter motor was what did for it? The electrical side isn't my strong suite, but am I correct in thinking that the ignition signal from the HES also serves the injectors? This would explain why I had no spark or injector signal. Clearly, I currently have both, but for how much longer and how reliably? Time for a new HES I think, so which one? Motorworks and the other aftermarket suppliers sell the HES for around £180, but I see that Dan Cata's boxer-upgrades site offers 2 versions of the HES, - standard for $110, or the fully waterproof version, shown working underwater on his Youtube video for $220. Either way it works out cheaper, but I'm more interested in long term reliability. Does anybody have any experience of Dan's HES or am I better off sticking with the standard item ?

I'd appreciate any comments or opinions and once again, my thanks for all the help so far.

Cheers,

Mac
 
Well your HES has lasted 15 years, so is it worth buying anything other than a standard unit. If what you buy lasts another 15 years, then........................

The HES has 2 sensors mounted 180 degrees apart. One sensor fires both plugs (at the same time) and the other sensor operates both injectors (again at the same time). The system is about as basic as it comes and is referred to as a wasted spark. That's because even though both plugs fire, only the cyclinder with fuel and compression creates the bang when the spark fires. The other spark is on the exhaust cycle so wasted.
 


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