Triumph Rat Motorcycle Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
53 Posts
Discussion Starter #1
Hey all! I’ve had some strange issues with my 2006 after the weather went cold. Sometimes, when it starts, it will idle very low, then die. Once it does this, it will continue this behavior on each start attempt, until the power is cycled. Once the power is cycled, most times, it will start and run fine.
It seems as though I’ve traced this back to a strange variation in TPS voltage. On the first read, it was 0.8 at closed. I adjusted it to 0.6, then it read 0.68 after a restart. After another restart, it was at 0.63. This is very consistent with the “sometimes it starts” behavior, from what I can tell. Time for a new TPS, or could this be from another source? Just put in a new good battery. Idle stepper seems ok, it always adjusts the voltage 0.15 up from whatever it starts at in the test.
 

·
Registered
Joined
·
1,733 Posts
Vacuum leak or air-filter not seated correctly. In my case it was a poorly seated Pipercross filter causing this issue. I replaced with an OEM air-filter, reset the TPS for a final time and had no more issue.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #3
Since these values are all taken with the bike not running, how could an air filter impact the TPS voltage at closed throttle? It’s a hard stop on the throttle turn, that position should never change with the stepper off. For vacuum, the engine isn’t running.
 

·
Registered
Joined
·
1,733 Posts
There are a lot of strange things that happen in this world. If we had answers for everything, neither one of us would be here!
 

·
Registered
Joined
·
53 Posts
Discussion Starter #5
Fair fair. I’m not against trying it, but I’ve been in there a few times already. New filter, and all hoses have been triple checked. It baffles me that it’s random, and not at every startup. That’s what makes me think it’s electrical.
 

·
Registered
Joined
·
889 Posts
@slaserj have a faint memory of a similar poor idle issue on my '05 speedy related to either the fork harness clamp or the TPS mount. If your front harness clamp is already removed or shimmed up, take a close look at the TPS. Secured by a security torx bit on the left side of the throttle butterflies partly hidden behind a frame tube. In my case the TPS mounting bracket had a hairline crack allowing the TPS to move enough to cause the type of voltage variations you're seeing.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #7
@slaserj If your front harness clamp is already removed or shimmed up,
First thing I did when I got the bike :)

@slaserj the TPS mounting bracket had a hairline crack allowing the TPS to move enough to cause the type of voltage variations you're seeing.
I'll get in there again today, and do a much closer inspection. I loostened it for the adjustment yesterday, turned it to match the .6v at close, and retightened it. seemed like it was VERY snug when I first got in there, I checked to make sure there was absolutely no play. I think I'm going to try to do a run with "good" idle, and a run with "bad" idle, and compare ALL of the TuneECU diagnostic readings. See if absolutely anything is strange.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #8
Welp, I've tried just about everything in terms of adjustments. Still getting strange voltage readings, and now I've had it die on me twice at stoplights. I found a TB complete setup including TPS and Servo for $35 on ebay, so I ordered that. Here's hoping that fixes the issue, I'll update as to what happens.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #9
So here we are, new TBs, TPS, and Servo, IACV Calibrated, and Adaptation Reset, and same problem. So now I'm confused. What else even is there to try? Don't those three parts control the idle? Could this be the CPS going out? I've seen a few threads referencing that as a possible problem on different bikes. Any other ideas? I'm sitting here bummed, I love this bike, and don't want a silly issue like this to make it basically unrideable.
 

·
Registered
Joined
·
889 Posts
Must be frustrating, that's a lot of new parts. Perhaps the TPS was a red herring or one part of the problem. I'd go back to basics as @Ferris suggested - look for air leaks. You likely know this already - only 1/3rd of idle air goes through the idle control system, the rest still goes through the throttle. Any air leaks will make it difficult for the IACV to adapt and hold idle steady. One more thing to test since your symptoms started with cold weather - the air, coolant and cylinder head temperature sensors.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #11
Must be frustrating, that's a lot of new parts.
Quite.

One more thing to test since your symptoms started with cold weather - the air, coolant and cylinder head temperature sensors.
Yep, I'm going to look a lot closer at those sensors when I get home today, make sure the values all "make sense".

One more thing I've considered: After deleting the O2 with the CRM exhaust, I never did the "12 min tune" after resetting adaptation, as I assumed that the O2 sensor was required for that process to do anything meaningful. Is this my eff up? Does that process still do soemthing with the IACV and Servo during adaptation? Should I let it idle for the full 12+ min and see if that helps?
 

·
Registered
Joined
·
1,733 Posts
One more thing to maybe look at. Is there any freeplay in the throttle? I once adjusted mine out and got my hand slapped by my mechanic. Stuffing up the TPS and causing erratic idle was the likely outcome of my fiddling, but it was remedied before anything nasty happened? Just one more option.
Oh and by the way, I still have an entire throttle body/TPS etc sitting in the garage from my air-filter experience.😜
 

·
Registered
Joined
·
889 Posts
^^^ what he said. Forgot about this one. In an effort to compensate for the staccato off-idle fueling in early 1050 factory tunes I adjusted throttle slack out completely shortly after getting the bike. Made a tangible difference in off-idle fueling, throttle inputs were smoother puttering around about town. But idle went to crap. Took a while to figure out the obvious - without the TPS ever seeing 0% throttle as far as the ECU was considered it was not idling. Idle air control and idle tunes were simply not in use. Using TuneECU to view throttle opening while adjusting slack got me the best of both worlds, low throttle whiplash and steady idle, or as steady as this generation of ECUs ever produce.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #14
Well, it appears to be mostly fixed?? I wish I could say exactly what fixed it, but it was very possibly a combination of my many attempts. Just before it “worked”, I did one more TPS and IACV reset, along with a reset adaptation, then let it idle for 12 min. Once it heat cycled the fan a few times, I shut it down, then started it up, rode for about 30 minutes, absolutely no low idle. Power cycled a few times to make sure, and it seems to be fine now. I got a couple of “high idle” moments around 1.6k rpm, which settled after a couple of seconds, but honestly, nothing that surprises me on this older bike. So, a lesson: even if you don’t have an O2 sensor, you MUST do the 12 min idle tune after resetting the adaptations.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #15
Ladies and gentlemen, we're back! Exact same issue, has come back after about a week of riding. I'm defeated. What else can I even check? Is it time to just grab a new CPS? Thing is, the bike runs fine above 2k RPM, rides just as bat-sh*t as it ever did.
 

·
Registered
Joined
·
53 Posts
Discussion Starter #16
I hate to say it, but this may be the parting of ways for this bike. It's really frustrating to go out and try to ride, only to have the bike die at each stoplight along the way. Feels like my old XS650 with it's carbs full of ethanol gum, but even that thing idled better. Really upsetting, I'm starting to see that speed twin nearer and nearer in my future.
 

·
Registered
Joined
·
889 Posts
Gotta be frustrating. Since speedy runs well off idle it does sound like an air leak since fueling appears to be ok and you've seen a stuck high idle a coupla times. Get a chance to go through the intake to ensure everything is seated and sealed? Are the temp sensors producing sensible readings? Tried reflashing the factory tune?
 
1 - 17 of 17 Posts
Top