2002 1150GS misfire - Help!

[nock]

Hi guys, I'm new to the forum and would really appreciate some assistance.

I've got a 2002 high mileage? (70k) R1150GS which is running poorly. I bought it as a stolen recovered knowing it needed work doing.

Since I've had it I've given it a full service (oil / filters / plugs / end float & valve clearances). It was still running badly so put it into Vines in Guildford stressing money was tight. They put it on the diagnostics which showed no faults, balanced the throttle bodies and checked the resistance across the HT leads through the coil pack and told me it was higher than it should be.
I took the HT leads off and checked their resistances separately, one was shagged so bought a new set.

The bike still seems to have an intermittent misfire on the nearside pot (plug is sooty), and will not pull cleanly in reponse to throttle opening particularly under load, top end is pretty abysmal. It runs (i.e. doesn't stall / stop etc) but even at tick over you can hear the irregular grumble of intermittent misfire.

I plan to clean and check the coil's earth to make sure its good then check its resistance (although I don't know what its supposed to be) to establish if it too is shagged. Speaking to Vines on the phone they tell me the Hall effect sensor is a common problem and my description of the fault would be symptomatic of it beginning to fail. The only other things I can think of are a problem with the low tension lead, or damage to the ignition wires (seeing as it was previously stolen).

I wish I was in a position to swap some 'good' components over to save myself a fortune but with the Hall effect sensor quoted at £182 and the coil pack at £65 this is not going to be possible.

Any help would be appreciated even if its just what the coil resistance should be. I'm strapped for cash and need the bike to get to work!

Thanks guys!

 

[Old Codger]

Try Steptoe

Just up the A3 from you

May be able to wave his magic wand over it

What he dosent know about GS,s aint worth knowing

www.gsshop.biz

No main stealer prices either

Frank

 

[Crackshot]

Nock, would you mind pm-ing me please? Ta!

 

[Packer]

+1 on taking it to Steptoe, a member on here. www.gsshop.biz. He knows these machines inside out and costs way less than a franchised dealer. He also has the advantage of being a mechanic instead of a computer operating parts replacement executive.

If yours has the coil in the head set up try swapping them over, a well known weak point and at 70,000 miles could well be ready for replacement.

If it was the Hall sensor I'd expect both pots to be equally eratic.

Spares are cheaper used (usually with guarantee) from Motorworks, James Sherlock or Moto-bins.

 

[nock]

Can't PM

Crackshot I'd love to PM you but I'm not a 'subscribed tosser' and am at work so can't get past the web marshall to pay the subscription.

I'm on 07725339063 if you'd like to text me

 

[Packer]

Nock, would you mind pm-ing me please? Ta!

He can't, he isn't a subscriber.

 

[nock]

Steptoe has suggested I check the resistance in each of the injectors which should be 16 - 16.5 ohms, they will be less if defective (14 ish). I've checked them and they are both steady at 16.

He also suggested I swap the HT leads over to see if the misfire moves to the other side (o/s). I'll be trying that next but need to get home to clean the sooty n/s plug first so that I can tell which pot the misfires coming from.

 

[Stewart H]

Have a look in your yellow pages for injection services, I got mine cleaned, tested and fettled last year for £18 each, probably worth doing at that mileage anyway.

 

[ilkleyal]

All good pointers but also eliminate water as the cause, a little bit of water in the tank can cause exactly the same symptoms as an ignition fault leading to the misfire. The plug won't look wet either as on the next cycle it will fire and dry itself out.

With a stolen recovered you have no idea what could be in there. If the other methods don't cure it, run it till almost dry remove tank, check the drain is clear in the filler (big cause of water in the tank) drain tank completely and stand in a sunny spot until you are 100% certain that it is dry. BE CAREFUL and don't let kids or pets anywhere near

Not saying this IS your problem but well worth eliminating.

Al

 

[niko]

id also try swapping the plus around ,ive had a few brand new plugs that are faulty ,the quality of new plugs seems crap compared to a few years ago
but it does sound like it could be the coil

 

[nock]

Thanks for all the useful advice so far guys.

I forgot to mention that the previous owner had the throttle bodies ultrasonically cleaned just before I bought it.

I swapped the HT leads over and the bike would only run on one cylinder (the n/s where the plug had been sooty). I swapped them back and once again the bike would only run on one cylinder this time the o/s. This suggested to me that the coil was on its way out as I couldn't think of anything else.

I rang Vines to ask what the resistances should be in the coil (to make doubly sure I was on the right track) and they confused the hell out of me.

Apparently the resistance in the primary measured between terminals 1 & 15 should be 87 ohms (this was easy to work out as these numbers are printed on the coil and refer to the low tension power supply terminals).

They then said the resistance in the secondary measured across the terminals (which I took to be the two coil posts where the HT leads take their power from) should be 0.36 ohms.

Then they said the other secondary in the head should be 7.2 ohms (I'm guessing they meant the resistance in the HT leads themselves)

I haven't been able to effectively check these resistances yet as my multimeter is too complicated to get my head round.

If anyone can verify these resistance figures or shed a little more light on checking them I'd be grateful.

I spoke to Steptoe and he said that generally the coil on these GS's are bullet proof, so I'm still a little worried about spending the £65 on a new coil!

 

[niko]

Resistance: Primary Ω ~0.5
between terminals 15 and 1
Secondary kΩ ~7.5 when cold
between terminals 4a and 4b
check the resistance of your meters leads first and take that into account with your readings
there you go mate ,its from the bm service Manuel

 

[DollyRocket]

Is it a twin spark?

I have a spare stick coil and I ride through guildford on my way to and from work each day if you want to borrow to try out. I don't have a normal coil though.

Mike

 

[nock]

Is it a twin spark?

I have a spare stick coil and I ride through guildford on my way to and from work each day if you want to borrow to try out. I don't have a normal coil though.

Mike

Thanks Mike - its not a twin spark. If the coil you have is suitable for my bike I'd really appreciate it

 

[niko]

Thanks Mike - its not a twin spark. If the coil you have is suitable for my bike I'd really appreciate it

if mike is calling it a stick coil its for a twin spark only i am afraid mate

 

[nock]

OK - so I've checked the resistances in the coil.

The meters leads had a resistance of 0.3 ohms and when placed across terminals 15 & 1 (low tension supply) I got a reading of 0.8 (0.8 - 0.3 = 0.5). So the Primary was good!

Between the HT terminals (4a & 4b?) I got a reading of 7.21 thousand ohms, not massively below the 7.5 shown in the BMW manual, but is this enough to cause my problems?

I've had a chat with a few mechanics and the symptoms I've described and the results I've got from the tests I've done, suggested to everyone a defective coil.

I think I've gone as far as I can - so I've just ordered a new coil. Stay tuned for the result which should be in this afternoon.

 

[nock]

Problem solved

Sorry to resurrect a dead post - but just in case anyone was wondering I finally got to the source of the problem.

After replacing the coil I found the bike ran far better than before, smoother and quieter. But the bike would still not pull under load above about 3.5k revs although under that it seemed OK.

I checked the TPS voltage at rest and found it was completely out. It should have read 0.37v between pins 1 & 4, so I turned it clockwise until it showed the correct value and tightened the torx bolts. The only problem was every time I opened the throttle and allowed it to return to the stop I got a different voltage no matter how much I adjusted it. In the end I sent for a second hand TPS from Motorworks which again improved he situation a little but still the 3.5k rev issue remained.

I was about to start pulling my hair out and open my wallet to the BMW workshop when I saw some good second hand GS injectors on e-bay. I fitted them and it was like I had bought a new bike! What a miraculous difference.

I hope this has helped others out who may be experiencing similar problems.

 

[Crackshot]

Good good!

 

[Steptoe]

I was about to start pulling my hair out and open my wallet to the BMW workshop when I saw some good second hand GS injectors on e-bay. I fitted them and it was like I had bought a new bike! What a miraculous difference.

I hope this has helped others out who may be experiencing similar problems.

Simple test - Measure the resistance across the injector terminals - should be around 16

 

[nock]

Simple test - Measure the resistance across the injector terminals - should be around 16

I had done that already and it was correct at 16. I am guessing that the injector was jammed open.