My R1150GS (2003 twin spark) has problems starting when hot, it doesn't spark. It's been in to the garage and the hall sensor, stick coils, conventional coil and ecu were eliminated as possibilities. A diagnostic system check on ECU, on coils and caps said no power but had earth pulse. The side stand switch and gear change indicator appear to be working normally when tested. The alarm unit (META) was re-positioned from under tank into airflow as it was suspected that when the alarm got hot the immobilser was being triggered. This didn't make any difference. The alarm was removed as this was deemed the most probable cause. I took the bike for a run out. After running 20 miles it restarted after a fuel stop, 50 miles further on we stopped for about 15 minutes and it wouldn't start. We pushed it to a parking spot and left it for an hour and a half, came back to it and it fired first time. Any thoughts that I can pass on to the mechanic? TIA John.
Won't start hot
- Thread starter John P
- Start date
I probably shouldn't comment as I'm not experienced enough with these bikes. But thinking aloud, how did you eliminate the hall sensor? I only ask because this sounds similar to symptoms mentioned by others that turned out to be the hall sensor 
If it's only when is hot then i would be looking for something electrical, to start with at least.
What happens exactly when you try to start it. The starter turns it over? and...
If it's only when is hot then i would be looking for something electrical, to start with at least.
What happens exactly when you try to start it. The starter turns it over? and...
Mechanic fitted a new hall sensor, yes It did seem the most common fault to fit with the symptoms. When bikes hot after say an hours run , stop for 10 mins wont start, spins over fine ,dash lights up as normal but wont fire. Quick fuel stops 2or3 mins seems ok.
Hot starting problems, can be really difficult to diagnose without some test equipment or other visual aid. It depends on what your mechanic is using to fault diagnose.
If the oil temp indication on the RID is OK then the sensor could be OK as the feed to the motronic is the same as the display.
Could be Air temp sensor, but doubt in it's position it could be breaking down with heat or something.
That kind of just leaves the Lambda sensor, maybe. I'm not sure whether the bike would run or not with the sensor faulty.
The other thing that it could be is the heat is affecting an electrical connection somewhere.
Sorry I can't be more helpful, but something like a GS911 connected up and data logging during your trip up to the point of the occurrence of the fault, is just about all you can do. However, if it's fuel related the GS911 won't pick that up.
Ian
If the oil temp indication on the RID is OK then the sensor could be OK as the feed to the motronic is the same as the display.
Could be Air temp sensor, but doubt in it's position it could be breaking down with heat or something.
That kind of just leaves the Lambda sensor, maybe. I'm not sure whether the bike would run or not with the sensor faulty.
The other thing that it could be is the heat is affecting an electrical connection somewhere.
Sorry I can't be more helpful, but something like a GS911 connected up and data logging during your trip up to the point of the occurrence of the fault, is just about all you can do. However, if it's fuel related the GS911 won't pick that up.
Ian
Thanks Ian for your reply,Bike runs really well so thinking not lambda sensor but maybe try that next. As for the oil and air sensors, could they immobilise the bike if they were giving false signals?
Also we are looking poor connections. I'll post how I get on. Let me know if you think of anything else. Cheers John.
Also we are looking poor connections. I'll post how I get on. Let me know if you think of anything else. Cheers John.
Well Bikes gone back into the shop today, but he's scratching his head . Talking about a possible wiring fault. Sound expensive! Going to try a oil temp sensor first and have a think. I may have misled you in my first post, the earth pulse to the coils is there when cold but not when hot,hence no sparks. Anyone with any ideas shout up please, Thanks John.
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get rid of the alarm on the bike , ive never had a alarm in over 20 yrs on a bike
Fanum
Toubab
Next time it happens, open the fuel filler cap and see if it will start 
Fanum
Toubab
Beware 'diagnostic readings'
On a 911 plug for example, it will report that there's a fault in a certain system, but it doesn't necessarily mean that that's where the fault lies......it may just be that first sensor that sends back a fault to the ECU was on that system, but the fault was caused elsewhere and the first place it caused a record of that fault was in a related system, IE the first one that was monitored, If that makes sense
To put it in silly terms, if you have a puncture without a tyre pressure monitor on board a vehicle, the first 'system' that the puncture may show up on is as a 'steering fault'.
Unless you've physically seen that there are no sparks at the HT lead ends, don't accept that a diagnostic device telling you that there aren't is correct
Seems to me that when you have this sort of problem, you have to go right back to basics......spark, fuel, air, then onwards from that point.
Borrow an ecu from someone. This is where the switching for the coils is done. Must be somebody on here with one you could borrow. It's very unusual for wiring to give a problem when hot.
Fanum
Toubab
Just to clarify....when you say the " hall sensor, stick coils, conventional coil and ecu were eliminated as possibilities", how were they eliminated?
If it was by physically swapping out those components for known to be working at 100% ones, they can be left out, but if they were 'diagnosed' in some other way, maybe not.
The lack of spark seems (to me anyway) to be critical........FACT: If there's no spark, there won't be combustion.
Again though, (and I'm not doubting you) how was that certainty reached?
If there was no spark at the plug/s (even one pair will do, out of the 2 pairs you have) but there was an HT jolt from the primary coil, it's got to be the leads or timing (HES)........
I've been around this circuit once, and that took nearly a year to solve........each time I thought I'd narrowed it down, I either replaced with new or swapped out for known working and compared my bike with the donor of those parts.
I lost track of where I was TBH (the threads are still here) and was probably going around in circles.
So I'd be inclined now, in your shoes, to sit and go through a logical list going right back to the basics, and double check that each step has been fully and properly eliminated, so you don't end up spending huge amounts of money on a misdirected assumption or diagnosis
EDIT........also establish the facts for yourself.......your mechanic may be great, but everyone is fallible, so don't take it as gospel when he says he's tried something.....check it and strike it off the basics list yourself
If it was by physically swapping out those components for known to be working at 100% ones, they can be left out, but if they were 'diagnosed' in some other way, maybe not.
The lack of spark seems (to me anyway) to be critical........FACT: If there's no spark, there won't be combustion.
Again though, (and I'm not doubting you) how was that certainty reached?
If there was no spark at the plug/s (even one pair will do, out of the 2 pairs you have) but there was an HT jolt from the primary coil, it's got to be the leads or timing (HES)........
I've been around this circuit once, and that took nearly a year to solve........each time I thought I'd narrowed it down, I either replaced with new or swapped out for known working and compared my bike with the donor of those parts.
I lost track of where I was TBH (the threads are still here) and was probably going around in circles.
So I'd be inclined now, in your shoes, to sit and go through a logical list going right back to the basics, and double check that each step has been fully and properly eliminated, so you don't end up spending huge amounts of money on a misdirected assumption or diagnosis
EDIT........also establish the facts for yourself.......your mechanic may be great, but everyone is fallible, so don't take it as gospel when he says he's tried something.....check it and strike it off the basics list yourself
Hi Fanum thanks for your input. The Hall sensor, stick coils and conventional coil were changed for new parts, started fine cold but not when hot .The ECU was changed for a second hand one from a reputable breaker, same result. The original parts were then refitted. It's as if something is immobilising the bike when it's hot, and not even that hot only normal running temp, 5or6 bars.
Sorry to hear this isn't fixed yet. It sounds maddening!
I've been away this week and no access to checking the forum so sorry if this has already been mentioned, but does the bike have am alarm system? I just read some other threads and it gave me the thought?
Other than that, Fanum's suggestions make good sense
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I've been away this week and no access to checking the forum so sorry if this has already been mentioned, but does the bike have am alarm system? I just read some other threads and it gave me the thought?
Other than that, Fanum's suggestions make good sense
Sent from my iPad using Tapatalk
cele0001
Registered user
After exhausting all the obvious here is a possibility
I had a similar situation with my 04 Rockster. It would start fine cold but warm it would feel like a weak battery.
Long story short it was the starter. I am assuming that the current draw from a bad starter was large enough to bring the voltage down enough to make the ME not work. One year later no issues.
Just a thought.
I had a similar situation with my 04 Rockster. It would start fine cold but warm it would feel like a weak battery.
Long story short it was the starter. I am assuming that the current draw from a bad starter was large enough to bring the voltage down enough to make the ME not work. One year later no issues.
Just a thought.
When you say that, do you mean you had exactly the same symptoms ie. won't start from hot when left for 10 mins?
And what fixed it for you? (apart from Jimmy)
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