Both Secondary coils dead?

[Bendy toy]

As Steptoe said, warm the bike to full running temperature then pull the trigger connectors to the secondary coils. If the engine feels no different the coils are suspect. If it does feel different reconnect one coil at a time to work out which is failing.

But if they are like the primaries, once one has gone the other wont be far behind.

Has anyone tried fitting remote mounted coils with HT leads? Heaven forbid that anyone could suggest such old school methods, but the coils could be located out of all the rain and salt spray and they are secondaries for goodness sake.

I just found this - http://easyautodiagnostics.com/coil_on_plug/cop_coil_tests_1.php

 

[The smudger]

Evenin`

After a fairly long ride the other week, Lowestoft to Lands end an back, Over half of it in the hissin rain .
My 05 gs ran really lumpy at anything under 3000 rpm, After 3k its like someone flicked a switch, Suddenly really picks up an goes great, But shite under 3k.
Its bloody irritating when filtering.

So Ive pulled the plugs These are the left cyclinder



An the right




S an M = Secondarys an Mains

Would both secondarys die an show this up?

Ive disconected the leads with the bike running, Every coil i disconnect causes a change in tone??

But i havent tried riding it on just Mains or just secondarys yet,

Any advice

What Steptoe said +

The secondary plugs are only there to mop up emissions. If the O2 sensor sees a high voltage (rich) the BMSK will fire the secondary up to c. 60 degrees after the primary has fired, just to burn off any hydrocarbons present. In a nutshell they do not fire all the time, only when emissions are high. That would explain the different colours.

So....

If your bike always idles differently when you disconnect the secondary It would suggest there is an underlying problem, i.e. the bike, for some reason is running rich, and the BMSK is firing the secondary in order to burn off the additional fuel present.

Hope this helps?

 

[Paul90]

What Steptoe said +

The secondary plugs are only there to mop up emissions. If the O2 sensor sees a high voltage (rich) the BMSK will fire the secondary up to c. 60 degrees after the primary has fired, just to burn off any hydrocarbons present. In a nutshell they do not fire all the time, only when emissions are high.

Hope this helps?

Umm, not sure about that.
When I was trying to find which of my coils was failing I used a spare plug (grounded) and connected each coil to it in turn while the engine was running.
I seem to remember they were all sparking quite a lot.
My coil was only failing intermittently when under load.

Steptoe's method is the way to go IMHO

Paul

 

[Bendy toy]

The sooty plug looks like mine when the first primary coil failed.

The bike started fine but when warmed up was lumpy at low revs and sometimes did the 2 stroke style burble like they do when coming on the pipe. Fuel consumption fell to 35mpg.

My guess is the coil fires intermittently so not all the oxygen gets used. The ECU sees the excess O2 so pumps in more fuel and we end up with an over-rich mixture.

Swap the primary coil to the other side. If the sooty plugs swap over its the coil. But if its like mine was you'll get all sorts of strange symptoms to cloud the diagnosis. If it is the primary dont be surprised if the other one follows along soon after.

Regarding secondary coils. Has anyone tried three wire car stick coils with short HT leads? The cost savings are considerable.

 

[vikingiii]

Secondary coil

What Steptoe said +

The secondary plugs are only there to mop up emissions. If the O2 sensor sees a high voltage (rich) the BMSK will fire the secondary up to c. 60 degrees after the primary has fired, just to burn off any hydrocarbons present. In a nutshell they do not fire all the time, only when emissions are high. That would explain the different colours.

So....

If your bike always idles differently when you disconnect the secondary It would suggest there is an underlying problem, i.e. the bike, for some reason is running rich, and the BMSK is firing the secondary in order to burn off the additional fuel present.

Hope this helps?

Is this a fact or what you believe?

I'm asking because it is not how BMW explains it.

Below is an explanation provided by BMW in 2004 (BMW R1200GS Press Release). I think it explains rather well how the secondary coil is working (actually how both coils are working).

Featured in all BMW Boxers since 2003 (with the exception of the 850cc power units), dual ignition has been further modified and improved on the R1200GS. The auxiliary spark plug is now arranged at the outer edge of the cylinder, the ignition timing of both plugs being freely programmable as a function of load and engine speed in order to further optimise running smoothness, emission management, and fuel economy. Referred to as "phase shift", this adjustment process is maintained consistently all the way from part load to full load.

In practice, this means different ignition timing points on both spark plugs in defined control map areas. When approaching full load, where dual ignition no longer provides any benefits, the phase shift effect is so large that the spark crosses over on the auxiliary plug in the expansion cycle (60 degrees at TDC). For all practical purposes this corresponds to single ignition on the central spark plug under full load.

 

[Pukmeister]

Is this a fact or what you believe?

I'm asking because it is not how BMW explains it.

+1, I always followed the BMW explanation.

 

[The smudger]

Umm, not sure about that.
When I was trying to find which of my coils was failing I used a spare plug (grounded) and connected each coil to it in turn while the engine was running.
I seem to remember they were all sparking quite a lot.
My coil was only failing intermittently when under load.

Steptoe's method is the way to go IMHO

Paul

OK, the first explanation was a bit 'loose' due to the fact I was trying to keep it simple....

When youre bike is idling the secondary coils will fire almost continually due to the design of the engine. On part or full load the engine can deal with the emission issue so they switch off.

Again, in short the secondary plugs DO NOT fire constantly.

Is this a fact or what you believe?

I'm asking because it is not how BMW explains it.

Below is an explanation provided by BMW in 2004 (BMW R1200GS Press Release). I think it explains rather well how the secondary coil is working (actually how both coils are working).

Featured in all BMW Boxers since 2003 (with the exception of the 850cc power units), dual ignition has been further modified and improved on the R1200GS. The auxiliary spark plug is now arranged at the outer edge of the cylinder, the ignition timing of both plugs being freely programmable as a function of load and engine speed in order to further optimise running smoothness, emission management, and fuel economy. Referred to as "phase shift", this adjustment process is maintained consistently all the way from part load to full load.

In practice, this means different ignition timing points on both spark plugs in defined control map areas. When approaching full load, where dual ignition no longer provides any benefits, the phase shift effect is so large that the spark crosses over on the auxiliary plug in the expansion cycle (60 degrees at TDC). For all practical purposes this corresponds to single ignition on the central spark plug under full load.

It's fact, kept simple....

 

[vikingiii]

OK, the first explanation was a bit 'loose' due to the fact I was trying to keep it simple....

When youre bike is idling the secondary coils will fire almost continually due to the design of the engine. On part or full load the engine can deal with the emission issue so they switch off.

Again, in short the secondary plugs DO NOT fire constantly.



It's fact, kept simple....

When you provide facts I will believe you, until then I rely on BMW's explanation.

 

[Bendy toy]

What evidence? BMW's explanation fits Smudger's.

As the secondaries are not used all of the time and dont need to be a particular shape I do wonder if lower cost coils could be used with HT leads. This would save money because £80 per coil is really taking the P and it would put them out of all the dirt and road spray so they (should) last longer.

This is for FOUR coils for goodness sake!!!
http://www.ebay.co.uk/itm/NEW-RENAU...arts_Vehicles_CarParts_SM&hash=item439fc3be89