Follow on from recent “won’t start” post. Engine was running rough, then wouldn’t start. New Hall sensor was fitted, and I assumed that was the poor running problem fixed. Wrong! So tried changing plugs, emptied out fuel and replaced, added injector cleaner, balanced throttle bodies. Something seemed to have worked, running about 90%, so set off home. By the time I got back, it felt like it was running on one cylinder, but both exhausts were hot. What would be the next check, replace coil? Injectors? Any tips much appreciated.
1150 gs not pulling
- Thread starter Mullgs
- Start date
Yeah, it’s fine
Is the bike a single spark or a twin spark?
single spark could be the coil breaking down. HT lead breaking down.
twin spark could be one of the primary coil sticks breaking down.
single spark could be the coil breaking down. HT lead breaking down.
twin spark could be one of the primary coil sticks breaking down.
Single spark. Struggles more under load, going uphill, made me think of coil but I’ve never had experience of injector faults.
Unless you have a split/leaking hose in the tank causing a drop in fuel pressure, The rubber U hose is prone for splitting.
I would be inclined to go for the coil breaking down under load, or HT leads.
I would be inclined to go for the coil breaking down under load, or HT leads.
Can you briefly run it up in the dark and look for HT tracking (blue sparks around the HT leads etc)
Not seeing any.
I would start by checking fuel pressure. Tee into the line and fit a small gauge.
Coil off, putting the multi meter across the HT terminals gives me 7.33 ohms, electrical terminals gives me 0.9 ohms, is this the problem? While I’m in there, how do I test the leads for continuity? TIA.
Injectors are spraying, and it ticks over. Don’t have access to a gauge
You are unlikely to find the cause of your problem by a resistance check of the coil. When the bike starts to loose power, it could be that the coil is breaking down. As the coil needs to work harder at higher rpm then it heats up and when it does its internal resistances changes You wouldn’t necessarily notice this by just reving the engine, it has to be felt under load. This is why coil faults, either misfire rough running or loss of power are generally diagnosed under load.
If you think it could be fuel related, and as you don’t have the means to test the pressure, then you could try disconnecting and capping off the fuel return line. This would take the fuel pressure regulator out of the fuel system and charge your fuel rail at the maximum pump pressure. Of course if your pump is down on flow because of wear or you have a leaking hose inside the tank then this might not achieve anything and the increased pressure in the fuel rail could amplify any leak inside the tank.
Normal fuel pressure is between 2.8 - 3.2 Bar, which is controlled by the pressure regulator and should be a constant throughout the rev range. The injectors can cope with an increase in pressure by opening for a shorter period, controlled by the motronic and lambda. (Closed loop).
The trouble comes when there is insufficient fuel through a drop in pressure at the higher loads and speeds.
The other thing to consider with the fuel is that after the pump, you have a fuel filter. This can restrict the flow if it’s partially clogged.
If you think it could be fuel related, and as you don’t have the means to test the pressure, then you could try disconnecting and capping off the fuel return line. This would take the fuel pressure regulator out of the fuel system and charge your fuel rail at the maximum pump pressure. Of course if your pump is down on flow because of wear or you have a leaking hose inside the tank then this might not achieve anything and the increased pressure in the fuel rail could amplify any leak inside the tank.
Normal fuel pressure is between 2.8 - 3.2 Bar, which is controlled by the pressure regulator and should be a constant throughout the rev range. The injectors can cope with an increase in pressure by opening for a shorter period, controlled by the motronic and lambda. (Closed loop).
The trouble comes when there is insufficient fuel through a drop in pressure at the higher loads and speeds.
The other thing to consider with the fuel is that after the pump, you have a fuel filter. This can restrict the flow if it’s partially clogged.
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