whats the point of an engine management light

[fizzer]

my 2011 twin cam gs 25000 miles has felt a little unsmooth when shutting of the throttle also a little on/ off when riding in town .
so this morning after a process of elimination i have worked out its the bottom rhs stick coil (new one on way from motorworks)
but my point is should this not have flagged up on the dash in the way of an an engine fault. ie management light .

 

[The Grey One]

my 2011 twin cam gs 25000 miles has felt a little unsmooth when shutting of the throttle also a little on/ off when riding in town .
so this morning after a process of elimination i have worked out its the bottom rhs stick coil (new one on way from motorworks)
but my point is should this not have flagged up on the dash in the way of an an engine fault. ie management light .

Engine management lights are there to show up faults (surprisingly!) with the engine management system. You didn't have a fault with that system.

John

 

[fizzer]

yeh i know ,with a car if you have a misfire ie coil goes down it puts the light on the dash ,thought it would do the same on the bike

 

[Bungy]

The first I knew of coil pack failure was the engine cutting out in the 3rd lane of the motorway.

 

[The Grey One]

yeh i know ,with a car if you have a misfire ie coil goes down it puts the light on the dash ,thought it would do the same on the bike

Don't think so, Tell me which cars do that. The misfire might cause a problem with the emission control system which could in turn put on the light but that is not the same thing. Plugging in a diagnostic machine will not show up the true cause. In the old days (remember I am ancient) we used Crypton machines which did check the ignition systems, you could see what each cylinder was doing.

John

 

[Ted]

Diagnostics for management lights usually works on 2 things. Continuity ( broken or poor connection) or more usually resistance falls outside preset values. example is ECU looks for 11.6 volts to 13.5 volts if 11.5 volts light will come on and ecu will usually switch off the faulty unit and substitute a fixed value so vehicle will still run. So you know theirs a fault it puts a warning light on. With the coils as far as ECU is concerned it is still working as in continuity and still firing but spark voltage is going via an easier route to head/cam cover rather than fire the plug, so misfire. Just because computer says all ok not nessaserily so. It only uses a very small current to run its internal and external diagnosis so can often not "see" a poor or bad connection that wont take full battery/running current. You still need good old fashioned diagnostic skills, which seem to be sadly lacking these days. feel a rant coming on..

 

[The Grey One]

Diagnostics for management lights usually works on 2 things. Continuity ( broken or poor connection) or more usually resistance falls outside preset values. example is ECU looks for 11.6 volts to 13.5 volts if 11.5 volts light will come on and ecu will usually switch of the faulty unit and substitute a fixed value so vehicle will still run. So you know theirs a fault it puts a warning light on. With the coils as far as ECU is concerned it is still working as in continuity and still firing but spark voltage is going via an easier route to head/cam cover rather than fire the plug, so misfire. Just because computer says all ok still need good old fashioned diagnostic skills, which seem to be sadly lacking these days. feel a rant coming on..

Too true, do they even teach them the basics these days? When I started one of the best pieces of advice I was given was to assume nothing and start from basics. I have see supposedly skilled "technicians" waste hours testing a non starting vehicle, lots of fancy diagnostics etc, only to find that the fuel gauge was telling lies and the reason the car wouldn't start was it had no fuel! Maybe we can get together over a pint and rant in unison.

John

 

[fizzer]

ok guys cheers for the input ,seems like i deduced what was not working by the process of elimination

 

[DrFarkoff]

All the EML can do is tell you if a process was faulted "BUT" only on the Loom / ECU side of the fault

for example in your coil stick its a low voltage trigger that has a good circuit but the HV side has a fault there is no link to let the ECU know this "Except" an effect Perhaps less fuel on that cylinder as the Lamda is showing it as running rich!

But again you need to be able to access live data to see this fault

Same with Fuel pump controllers they fault on the pump side so as far as the system is concerned its making a circuit to start the pump "But" its broken on the pump side not the loom/ ECU side. The Effect is easily diagnosed Engne noe run wee fuel pump well full of water (Well designed NOT!!!)

 

[horsetooth]

Bmw Cars do register fault codes for coil packs and if its a 6 cyl it even tells you the one that has failed .

 

[fizzer]

Bmw Cars do register fault codes for coil packs and if its a 6 cyl it even tells you the one that has failed .

cheers i thought so,even a something as simple as a corsa when the eml comes on ,and you plug in to the obd it tells you whitch coil has the misfire .

 

[horsetooth]

on a corsa for instance its code p3000 and thats cylinder misfire but they rely on some common sense that you would swap around the coil packs to see if the cylinder number changes .
for instance on a 325i it would say cylinder misfire no 4
so you would swap number 4 coil pack with say 6 you would always try the easiest option first.id be surprised if gs911 doesnt have a code for cylinder misfire .

 

[Steptoe]

.id be surprised if gs911 doesnt have a code for cylinder misfire .

It doesn't if the misfire is caused by a failed coil stick. It's too far downstream for such an old system designed in 2004 for a motorcycle.

 

[TLSgazza]

Bmw Cars do register fault codes for coil packs and if its a 6 cyl it even tells you the one that has failed .

Mine even tells me if a bulb has blown even if I've not even turned the lights on. I voodoo I'm telling ya

 

[younger06]

Mine even tells me if a bulb has blown even if I've not even turned the lights on. I voodoo I'm telling ya

Stop now lads....... this is getting scary!

Sent using hocus pocus........... boo!

 

[Bendy toy]

The R1200 stick coils are silly money and I believe the secondaries are even more than primaries and are not even swappable left/right.

Has anyone tried a lower costs car stick coil (three wire type) with an HT lead to the plug?

 

[horsetooth]

The R1200 stick coils are silly money and I believe the secondaries are even more than primaries and are not even swappable left/right.

Has anyone tried a lower costs car stick coil (three wire type) with an HT lead to the plug?

got all 4 stick coils in gwo i have spare if any one local needs to eliminate a fault then they are welcome to try them.

 

[Bendy toy]

The coil with HT lead would not work on the primaries - lead would be impossible to fit to the plug. But it might work on the secondaries. For what car coils cost I will be trying it when my secondaries fail.