Tiger running poorly - things to look for please

[ChazzyB]

My Girly isn't running well. It started last Sunday, I'd been for a ride with no detected issues. Parked up for a cup of tea and 20 minutes later, when I tried to start her... difficult to start, hesitating or even stalling as soon as I tried to open the throttle, slight misfiring, still on the stand in neutral, more popping on closing the throttle than I'd expect. I managed to start and keep it running and rode home about 20 miles. I found that as soon as I could get over the initial throttle opening, under a slight load, it ran just fine - full power for overtakes etc. On the road, shutting the throttle  felt like the engine had died, opening it again was somewhat abrupt, all or nothing. When I pulled into my drive, it idled fine, no hesitation on the throttle and seemed to be running fine again. A quick two mile ride and it was displaying the hestitation, stalling popping again. Into the garage it went I and locked the door.

This afternoon, I did a TPS reset with TuneECU, started it up just fine from cold and I let it idle without touching the throttle until the fan came on. Switched off, and restarted with a bit of hesitation - I had to give it a bit of throttle - and then displayed the same symptoms as last Sunday. Not good.

Oh, and when in neutral, if I give it some throttle and let go, the revs drop to about 1700, then take a couple of seconds to fall back to 1200-1300 RPM.

No error codes logged. Where's the clever money for things to look at/replace first?

Yours, slightly worried...  :?

[Timbox2]

Questions first

1) More details about the bike please year mileage etc
2) Bike been laid up for a while until last Sunday?
3) And I know it sounds condescending but anything else you aint told us about, like, last week you stripped the alarm out or fitted 3Kw Running lights.

Seriously Only joking but its part of the fault finding process, and being an IT Engineer i always try and get at what someone may have forgotten to tell me, you never know.


My gut reaction would be to check out the IACV  stepper motor though not everything points to that but its a start and it wont cost anything to whip the tank off and have a look see, when mine went I got a lot of the symptoms you have but Crank sensor or TPS itself could also do that as could the ECM module or wiring or, or ,or


Ohh, and dont be worried, if all else fails set fire to the f..... :lol:

[ChazzyB]

Phew, early 2003, 45K miles, not been laid up, used most week-ends for a tank-full or more.

Only thing done recently was trying to suss out why the Scottoiler had stopped oiling. I pulled the vacuum pipe off the top, tested for suck (it worked another reservoir I had on the shelf) and replaced pipe. Pipe is well pushed in again and sounds like it's lifting the reservoir valve. Certainly it now delivers oil.

The bike does burn some oil if used hard (don't they all?)

[Timbox2]

Phew, early 2003, 45K miles, not been laid up, used most week-ends for a tank-full or more.

Only thing done recently was trying to suss out why the Scottoiler had stopped oiling. I pulled the vacuum pipe off the top, tested for suck (it worked another reservoir I had on the shelf) and replaced pipe. Pipe is well pushed in again and sounds like it's lifting the reservoir valve. Certainly it now delivers oil.

The bike does burn some oil if used hard (don't they all?)

Ahaa, here we go, Scottoiler, check where the vacuum take off is on the IACV piping, its caused problems in the past on a few, and check its not fouling the accelarator linkage

[Bixxer Bob]

I'm 99% certain this is an air-related issue.  Like Tim says, sounds like the IACV is playing up.  You can test it with Tune ECU with the ign on and engine off, listen carefully and you'll hear it cycling.  If it isn't a smooth run from end to end during the test it's sticking (fairly obvious that...) around £70 to replace.

Since you've been at the Scottoiler vacuum connection, I'd have a really good look at the IACV hose(es) just to make absolutely sure they aren't leaking.  A small split between the corrugations would be a beggar to find and would also give the sort of intermittent problem you have. As would a leak where they've been cut into to fit the Scottoiler T piece.

Oops, just beat me to it Tim!

[Timbox2]

I'm 99% certain this is an air-related issue.  Like Tim says, sounds like the IACV is playing up.  You can test it with Tune ECU with the ign on and engine off, listen carefully and you'll hear it cycling.  If it isn't a smooth run from end to end during the test it's sticking (fairly obvious that...) around £70 to replace.

Since you've been at the Scottoiler vacuum connection, I'd have a really good look at the IACV hose(es) just to make absolutely sure they aren't leaking.  A small split between the corrugations would be a beggar to find and would also give the sort of intermittent problem you have. As would a leak where they've been cut into to fit the Scottoiler T piece.

Oops, just beat me to it Tim!

Im fast me, to your credit BB think It was one of your posts about the scott oiler that I was recalling

[ChazzyB]

The Scotty pipe was in at the IACV end, albeit not as far as I'd have liked.

I'd wonder about the IACV stepper, but wouldn't it have problems during the start-up and warm-up phases? Starting from cold this evening, it started on the button and fast idled normally during warm-up and gradually reduced until up to temp.

Is it OK to reconnect the battery and use TuneECU the check the stepper with the tank off?

[Bixxer Bob]

The warming up will mask a tickover problem as the ECU enrichens the mix and raises the tickover depending on engine temp.  Having said that, if it re-starts ok once warm, meaning the problem is intermittent, prob still points to an air leak.  The tickover being high then dropping to normal is classic.  Have a really good look at the Scottoiler connection.

And to answer your question, yes, you can re-connect the battery with the tank off to check the IACV.  If you put the tank on a B&D workmate and snip through the tie-wrap holding the fuel pump loom to the injector rail, you can hook up the fuel and run the engine too.  Then waggle the hoses to see if you can make it play up.

[ChazzyB]

Thanks chaps. I've checked the stepper motor action with TuneECU and seen it calibrate then cycle in and out severl times. I'll whip the entire assembly off tomorrow evening and check it plus the hoses for damage. Will seem weird if it is the Scotty. I must have started and used the bike from cold and hot about half a dozen times between investigating the poor chain lube delivery and being struck down. Hey ho!

[Bixxer Bob]

Be careful cycling the IACV off the bike.  Mine shot parts all over the garage and I ended up having to replace it.

I still think you've deffo got an intermittent air leak somewhere though judging by the reluctance to drop straight back to idle revs when you blip it.

[Timbox2]

Be careful cycling the IACV off the bike.  Mine shot parts all over the garage and I ended up having to replace it.

+1 Me Too  :oops:

[ChazzyB]

Eek, I didn't intend to activate the IACV while it's off the throttle bodies, just clean it and look at the hoses closely. I picked up a couple of throttle body gaskets (always good to have spare gaskets) today at lunch time. I'm also toying with the idea of forking out the required £40 and replacing the TPS while I'm in there, regardless. The fount of all knowledge at my local dealer said his money would be on the TPS. He also rides a Girly...

[Timbox2]

Eek, I didn't intend to activate the IACV while it's off the throttle bodies, just clean it and look at the hoses closely. I picked up a couple of throttle body gaskets (always good to have spare gaskets) today at lunch time. I'm also toying with the idea of forking out the required £40 and replacing the TPS while I'm in there, regardless. The fount of all knowledge at my local dealer said his money would be on the TPS. He also rides a Girly...

If he does turn out to be the Font of all Knowledge with Girlies, cherish him, they are few and far between

[Bixxer Bob]

Be careful cycling the IACV off the bike.  Mine shot parts all over the garage and I ended up having to replace it.

+1 Me Too  :oops:

[ChazzyB]

An update: throttle bodies have now been off twice, latterly to fit a new TPS (and reset via TuneECU). Sweet FA difference. Cold start, all AOK: fast idle, decreasing in steps until idling ~1250 rpm; didn't touch throttle. Switched off after fan cut in. Wait a couple of mins and restart. Yuk, same problem. Stalling off idle, misfiring, hanging around 1500 rpm for a second after blipping the throttle (assuming it hadn't stalled).

I've just been out again after an hour, hooked up my laptop and TuneECU again. Started bike and watched the O2 sensor voltage. Initially it showed 0.45V and as the bike warmed up, it dropped steadily until it got as low as 0.025V, where it hovered. This was at idle. Running the engine at higher engine speeds (~3.5-4K rpm briefly) would see the voltage rise slightly, but not a lot.

What's expected usually from the O2 sensor? A bit of net trawling suggests typical O2 sensor output cycling between 0.8V and 0.2V, but I guess this depends on the sensor and the ECU? Oh, and when I changed the plugs last weekend, I thought they looked a bit on the weak side.

Aaargh!