Cold start stumble...

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Tooltech
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Cold start stumble...

Post by Tooltech » Tue Sep 18, 2012 1:55 pm

2012 SMT 990 / 4600 miles / Akrapovic cans and map / 10-50 Lucas Syn. oil / started having cold ( less than 65 deg. F ) starting issues. The bike was perfect, one push of the starter equalled a good strong start. Now it takes 5 attempts to actually get a strong idle. After the bike is warm...perfect starts every time. Of course KTM has NEVER heard of this issue. The dealer is lost for an explanation.

My friend has a SMT setup exactly like mine and similar miles he also is starting to have the exact same results. My other LC8 powered bikes never had this type of issue. The other bikes all had Akrapovic cans and maps.

Please advise...
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Re: Cold start stumble...

Post by Gnosisdog » Thu Sep 20, 2012 6:30 am

Had this issue myself on occasion. Instead of repeatedly trying to start it, I tried turning off the ignition, then turned it back on, in the hope that it would reset. And it did- starts right up perfectly every time this way. Seems that sometimes the ECU does not switch to an enriched "choke" mode for a cold start. The 2nd time it gets it, not sure why. Never happens when bike is warm.

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Re: Cold start stumble...

Post by Tooltech » Thu Sep 20, 2012 6:51 am

Gnosisdog wrote:Had this issue myself on occasion. Instead of repeatedly trying to start it, I tried turning off the ignition, then turned it back on, in the hope that it would reset. And it did- starts right up perfectly every time this way. Seems that sometimes the ECU does not switch to an enriched "choke" mode for a cold start. The 2nd time it gets it, not sure why. Never happens when bike is warm.
Thanks for the input, I will try your solution and report back...
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Re: Cold start stumble...

Post by Gnosisdog » Thu Sep 20, 2012 7:45 am

Mine is completely stock BTW. So a good chance the Akra maps or cans are not be the prob. Wonder if there's a temperature sensor in the ECU that gets fooled or bypassed somehow.

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Re: Cold start stumble...

Post by Tooltech » Thu Sep 20, 2012 8:00 am

I have had the Akra cans and map from mile one. The bike had been cold starting perfectly...one press of the starter and perfect idle. I am interested to try the on / off / on and cold start procedure. When the bike is warmed up it starts perfectly.

By the way, my bike does not like Union 76 gas. When warm it runs ok but the cold start idle is rough compared to Texaco, Shell and Chevron ( Chevron is the best ).
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Re: Cold start stumble...

Post by vroum_ninou » Thu Sep 20, 2012 10:03 am

My bike does that also from time to time. It also sometimes stay at high idle rpm when warm and it takes 5 to 10 seconds for it to go down from around 2000 rpm to a normal idle rpm.
I've been having injection gremlins for a while now. We tried everything, to no avail. The only thing left is changing the electronic injection module.

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Re: Cold start stumble...

Post by Scutty » Thu Sep 20, 2012 11:12 am

I have noticed with mine, the outside temperature displayed always seems worng when the ingition first turns on then, within a few seconds, resets to the correct figure. I have no idea if that would fool the ECU but maybe the temp sensor just takes a few seconds to reset its reading?

Try putting you dash onto temp reading before you leave the bike at night then see what happens when you start up next morning.
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Re: Cold start stumble...

Post by Gnosisdog » Thu Sep 20, 2012 8:21 pm

[quote="Scutty"]I have noticed with mine, the outside temperature displayed always seems worng when the ingition first turns on then, within a few seconds, resets to the correct figure."

Does it read too high at first? If so that might be the issue.

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Re: Cold start stumble...

Post by Scutty » Thu Sep 20, 2012 9:34 pm

From what I can remember it reads high to start with.
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Re: Cold start stumble...

Post by Gnosisdog » Fri Sep 21, 2012 6:32 pm

vroum_ninou wrote: I've been having injection gremlins for a while now. We tried everything, to no avail. The only thing left is changing the electronic injection module.
That's disturbing news. Did you remap? One of Kev's Tune ECU ones? First thing I'd do, regardless of gremlins.

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Re: Cold start stumble...

Post by vroum_ninou » Fri Sep 21, 2012 9:10 pm

Gnosisdog wrote:
vroum_ninou wrote: I've been having injection gremlins for a while now. We tried everything, to no avail. The only thing left is changing the electronic injection module.
That's disturbing news. Did you remap? One of Kev's Tune ECU ones? First thing I'd do, regardless of gremlins.
I've had the official KTM mapping for the full Akrapovic line since the 600 miles maintenance in 2009. This year, while trying to find out the cause of my injection woes, we put in the 2012 full akrapovic mapping (I was thinking that may be there was a very remote chance that the mapping had gotten corrupted). It did not cure the gremlins.
We checked quite a few thing (admission, exhaust, TPS...), but I did not try to fiddle with the mapping. I'm supposed to have a good one and the bike has been fine for close to 50.000 km. It suddenly started to do this, so this should not be the mapping. All sensors seem fine. We did not replace the injection module because it's expensive and we're not dead certain it would fix the issue. It's only noticeable around 2 to 3500 rpm really (it's as if the bike was missing gas or air and it also started backfiring a little) and I've learned to live with it. The bike eggs me on to use it between 4500 and 8500 rpm anyway! ;)

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Re: Cold start stumble...

Post by yzinger » Fri Sep 21, 2012 9:36 pm

vroum_ninou wrote:
I've had the official KTM mapping for the full Akrapovic line since the 600 miles maintenance in 2009. This year, while trying to find out the cause of my injection woes, we put in the 2012 full akrapovic mapping (I was thinking that may be there was a very remote chance that the mapping had gotten corrupted). It did not cure the gremlins.
We checked quite a few thing (admission, exhaust, TPS...), but I did not try to fiddle with the mapping. I'm supposed to have a good one and the bike has been fine for close to 50.000 km. It suddenly started to do this, so this should not be the mapping. All sensors seem fine. We did not replace the injection module because it's expensive and we're not dead certain it would fix the issue. It's only noticeable around 2 to 3500 rpm really (it's as if the bike was missing gas or air and it also started backfiring a little) and I've learned to live with it. The bike eggs me on to use it between 4500 and 8500 rpm anyway! ;)
Did you check the valve clearance? What about the manifold pressure sensor?
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Re: Cold start stumble...

Post by vroum_ninou » Fri Sep 21, 2012 10:29 pm

Yup, valve clearance has been checked and I'm told that a faulty sensor would be detected and throw an error. There are no errors showing when the bike is plugged in.

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Re: Cold start stumble...

Post by yzinger » Sat Sep 22, 2012 1:22 am

vroum_ninou wrote:Yup, valve clearance has been checked and I'm told that a faulty sensor would be detected and throw an error. There are no errors showing when the bike is plugged in.
A bad sensor is only going to result in an ECU error if it's pegged one way or the other. If it's reading way off but still in the valid range there won't be an error. The key to me is that its runs bad at lower rpms, where the engine is most likely to be running on the L map (which uses the manifold pressure sensor).

I suppose one way to try to narrow it would be to set your F/L curve to zero above, say 2000 rpm and see if you notice a difference. Setting it to zero just means that above 2000 rpm, all throttle positions are now in the F curve.
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Re: Cold start stumble...

Post by vroum_ninou » Sat Sep 22, 2012 1:31 am

Thanks for the input Yzinger. I have not fiddled with the mappings. I don't have the knowledge, nor the tools to do that. But I'll talk to my mechanic about your suggestion next time I leave him my bike for maintenance.

Thanks!

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Re: Cold start stumble...

Post by kevxtx » Sat Sep 22, 2012 9:24 am

The Akra map is quite rich at idle, I had to lean that base map quite a bit for our Ozzy fuels.

I have experanced the conditions you speak of last year when the ambient temp was below 5C using the Akra map, try cranking the bike a few seconds longer, don't remove your thumb off the starter button as soon as it fires up let the starter motor run on for a few turns.

Things to check.
1/ Check the battery voltage when cranking, what are you getting?
2/ Check the Voltage at the starter motor while cranking, does the voltage dip below 10.5volts? If it does the motor won't be spinning fast enough for a good cold start.
3/ Try loading one of the maps from our map section.

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Re: Cold start stumble...

Post by Tooltech » Wed Oct 03, 2012 3:21 pm

Tooltech wrote:
Gnosisdog wrote:Had this issue myself on occasion. Instead of repeatedly trying to start it, I tried turning off the ignition, then turned it back on, in the hope that it would reset. And it did- starts right up perfectly every time this way. Seems that sometimes the ECU does not switch to an enriched "choke" mode for a cold start. The 2nd time it gets it, not sure why. Never happens when bike is warm.
Thanks for the input, I will try your solution and report back...
This on / off / on procedure works perfectly. I have tested it over some time and it is valid. I would suggest that everyone with this issue contact your KTM dealer and ask them to notify KTM. KTM must have a solution and needs to correct the problem with our bikes.
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Re: Cold start stumble...

Post by Gnosisdog » Wed Oct 03, 2012 4:20 pm

Glad it worked. I've learned to live with it but its a concern. I'm going to do a mod/remap next month so will see if that changes anything. Not hopeful as its a sensor issue is my guess.

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Re: Cold start stumble...

Post by cavlovic » Wed Oct 03, 2012 8:49 pm

Gnosisdog wrote:Glad it worked. I've learned to live with it but its a concern. I'm going to do a mod/remap next month so will see if that changes anything. Not hopeful as its a sensor issue is my guess.
Can it be that fuel pump needs to pump twice to build up pressure for start? Maybe fuel filter dirty or fuel pump faulty?
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Re: Cold start stumble...

Post by Gnosisdog » Wed Oct 03, 2012 11:07 pm

I'd think fuel pump issue would show in other areas. My bike fuels perfectly in every other context but that first cold start. This smells like some kind of a sensor/ECU thing.

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