Triumphrat

phendric · 08-06-2012, 01:23 AM

I've brought this issue up in another thread somewhere, but the things I've tried so far haven't worked, so I'm looking for additional suggestions.

Ever since getting my '01 Sprint, it has had a couple issues that seem related to the fuel system:

When held at constant (lower) throttle, it burbles a lot, and seems slightly rough,
When the engine is warm, and I release the throttle, it drops revs quickly to about 2,000 rpm, holds there for a moment (or three), and then drops, more slowly, to its 1,100-1,200 rpm idle speed,
The engine seems pretty dead under 2,500 rpm, but right around 2,500, it comes alive and pulls strongly all the way up to redline.

What I've done:

I checked the map, and uploaded a new one to the ECU with TuneECU, as the bike has a TBR can on it,
I pulled the tank and airbox, thinking that there might be something wrong with the IACV hoses. The vacuum caps at both ends were worn and cracking, so I replaced them with new ones. The hoses themselves look intact. I tested them by pulling them off, covering one end with a finger, and blowing in the other end.
I don't have a tool to check that the throttle bodies are synced, but a close visual inspection tells me that if they're out of sync, I can't see it.

I don't know if issue #3 above is actually an issue - it may just be how the bike behaves, but the first 2 issues are real, I think. None of the things I tested have made any difference to any of the points.

Where else should I be looking?

Thanks.

maxorbit · 08-06-2012, 02:20 AM

In terms of #3 .I think 2500 rpm is to low to be running around. I try to keep mine above 3K and usually 4-5 K around town.Not too often do I get out the 3rd gear.

Trade_nancy · 08-06-2012, 02:38 AM

Me too. 2000 model. Running around town at lower rpm in 3rd gear..motor does sound rumpity and almost feels erratic. Been like that for as long as I've had it and about 14000 miles. I put it down to it's personality...and not a fault.
Balancing the throttle bodies WILL help..did mine using a Morgan Carbtune.,,and things became nicer...but the low speed putter remains.

armarra · 08-06-2012, 03:18 AM

Quote:

Originally Posted by phendric

I've brought this issue up in another thread somewhere, but the things I've tried so far haven't worked, so I'm looking for additional suggestions.

Ever since getting my '01 Sprint, it has had a couple issues that seem related to the fuel system:

When held at constant (lower) throttle, it burbles a lot, and seems slightly rough,
When the engine is warm, and I release the throttle, it drops revs quickly to about 2,000 rpm, holds there for a moment (or three), and then drops, more slowly, to its 1,100-1,200 rpm idle speed,
The engine seems pretty dead under 2,500 rpm, but right around 2,500, it comes alive and pulls strongly all the way up to redline.

What I've done:

I checked the map, and uploaded a new one to the ECU with TuneECU, as the bike has a TBR can on it,
I pulled the tank and airbox, thinking that there might be something wrong with the IACV hoses. The vacuum caps at both ends were worn and cracking, so I replaced them with new ones. The hoses themselves look intact. I tested them by pulling them off, covering one end with a finger, and blowing in the other end.
I don't have a tool to check that the throttle bodies are synced, but a close visual inspection tells me that if they're out of sync, I can't see it.

I don't know if issue #3 above is actually an issue - it may just be how the bike behaves, but the first 2 issues are real, I think. None of the things I tested have made any difference to any of the points.

Where else should I be looking?

Thanks.

Surprised that you used tuneecu to look and load maps, but not aware it can show the TB balance.. is there something I am missing ??

connect your tuneecu again, start the bike and click on the diagnostic tab to see the 3 guages on the program showing the 3 cylinder balance.
Now to do this properly, having the numbers the same on each cylinder is NOT enough.
you need to keep screwing in the screw that is closest to all the way in and adjust the other two in steps to maintain balance..until one of the screws is fully in as far as it can go and the other two are out a bit and keeping the balance against the closed screw one. This makes the idle air circuit minimal and allows a smoother transition form idle air system to throttle body only system when you roll on the throttle from idle.

Also, before attempting this, ensure that your clamps around the TB are tight and that the TB is securely pressed against the intake adapters.

One other thing that comes to mind is the TPS. Once again Tuneecu to the rescue and there are threads on here to show how to do this. If the TPS is slightly rotated by accident wrt the throttle shaft, then the ecu might think that the throttle is closed even though it is open.

so. 1. Balance the TBs
2. Check TPS setting using tuneecu for completeness.

Alternatively, check that the air tubes from the ISCV are not disconnected or leaking air.

KitNYC · 08-06-2012, 04:01 AM

Armarra, please do a bit more research. I know you're trying to help, but giving people incorrect answers isn't really helping. Yes, TuneECU can reset the Throttle Position Sensor on 955 bikes. No, TuneECU can not balance the throttle bodies on them; that is a function of the Keihin ECU.

Phendric, 2500 is about where they start to pull. My second gen 955 would just cruise along with my hand off the clutch at a hair under 2k, but it definitely wasn't happy about it 'til 2500, and got much happier at 3k.

As for the other stuff, try doing a TPS reset and balance the TBs and see if that doesn't help.

Cheers,
-Kit

PaulM · 08-06-2012, 04:36 AM

Hello, I have had my 02 st from new every slow speed issue has either been cracked IACV hoses or spark plug problems. When I changed my hoses I could not see anything wrong with them but fitting new hoses cured an erratic tick-over issue I had. You do not need the corrugated triumph hoses good quality vacuum hoes will do and are far cheaper. Stuttering or misfiring has been water in the spark plug wells causing rusty plugs and a misfire. My bike has never been near a computer and runs better now than when it was new don't mess with tuning unless the bike is non standard.Fit new plugs IACV hoses and a new air filter to eliminate basic problems.
Cheers Paul

armarra · 08-06-2012, 07:32 AM

Quote:

Originally Posted by KitNYC

Armarra, please do a bit more research. I know you're trying to help, but giving people incorrect answers isn't really helping. Yes, TuneECU can reset the Throttle Position Sensor on 955 bikes. No, TuneECU can not balance the throttle bodies on them; that is a function of the Keihin ECU.

Phendric, 2500 is about where they start to pull. My second gen 955 would just cruise along with my hand off the clutch at a hair under 2k, but it definitely wasn't happy about it 'til 2500, and got much happier at 3k.

As for the other stuff, try doing a TPS reset and balance the TBs and see if that doesn't help.

Cheers,
-Kit

Kit, I was not aware that the sagem maps could not load the TB balancing part of the program, but evidently they can load the (2)tps and that may well account for his problem.

(3). ISCV hoses are also problematic as Paul confirms... I'm on track here but was arie on the TB setting method only - noted with thanks.

I reaffirm that the (1)TB balance will assist regardless of how he performs it.
I have a good track record on this site. None of us are bullet proof are we

armarra · 08-06-2012, 07:57 AM

Quote:

Originally Posted by Trade_nancy

Me too. 2000 model. Running around town at lower rpm in 3rd gear..motor does sound rumpity and almost feels erratic. Been like that for as long as I've had it and about 14000 miles. I put it down to it's personality...and not a fault.
Balancing the throttle bodies WILL help..did mine using a Morgan Carbtune.,,and things became nicer...but the low speed putter remains.

Hi Trade nancy,

I rode a 2004 955 for a few years(worked well at low revs) and have updated to 1050 in the same bike. Better response at lower revs, but had you considered.. that if the TPS has been rotated wrt the throttle shaft, then the ecu may be applying fuelling that is out of sync with
the throttle body opening.

Just a thought..
Tune ecu will allow this realignment on the 955.

phendric · 08-06-2012, 10:54 AM

I reset the TPS when I loaded the new map (2 weeks ago, followed by a week in Yosemite --> no riding). So I should:

1) replace IACV tubes, even if the current ones seem okay?
2) balance the TB? Is that something I can do on my own, or should I have someone do it for me?
3) check, and possibly replace, the spark plugs. Is there a special socket I need for those plugs? None of the ones I have seem to fit - they're all too thick!

I figured the lethargy below 2500 is par for the course, but thought I'd ask.

oldndumb · 08-06-2012, 11:06 AM

phendric and Trade_nancy, I've attached a trouble shooting sheet which can serve as a checklist. Most of it seems generic, but it is Triumph specific in some items.

phendric, if it were me I would check the TPS because your symptoms are occurring very close to the TPS/MAP switch over point. Checking your TPS, you will want to see a reading between 0.55 to 0.65 vdc.

scan0009.pdf

I see that you posted re the TPS while I was composing.

Balancing TBs is very simple with home made/commercial equipment. But it is not the panacea some think. It is a catchy phrase which seems to intrigue some. Time would probably be better spent on the IAC system, including cleaning the valve body.

Also remember, that inducing a high load on the engine at or below 2500 RPM will never be considered a good idea.