Yamaha's response to "Hard Start"

[mcbrien]

Could it be that with a marginal charged battery that when the starter is
cranking that there's not enough juice for the ignition so poor or no spark
is causing flooding. This new battery has got me thinking. :

 

[markjenn]

Could it be that with a marginal charged battery that when the starter is
cranking that there's not enough juice for the ignition so poor or no spark
is causing flooding. This new battery has got me thinking. :

Absoutely. But many of us have had hard starts with fully-charged (even brand new) batteries, so while a marginal battery is a contributor, it is not the root cause. On my last hard start, I had just charged the battery and I know it was reasonably good because I had to crank WOT for over a minute to clear the flooded condition. If I hadn't had a fully-charged battery, I'm certain I would have run out of charge before the motor cleared.

- Mark

 

[cakeboy]

has anyone had any starting problems on the new 2014 models ? .... if not there was a problem and yamaha have fixed it . having said that ive never had this hard start problem on mine , so another question why do some suffer from it and other dont ?

 

[Random ride]

I have done everything in this thread that would cause a hard start and absolutely none have happened. I didn't know about any of this hard starting until recently.

My 2013 was completely stock for the first 500 miles. I then added a Yosh muffler (have since went back to stock), and had AVC reflash my CPU. No issues either way. I've ran mine for a couple of minutes and shut it off only to restart it 5 minutes later. It has set for 3 weeks in between riding, no issue. I've always used either premium or the 90 octane alcohol free gas from my local station. My bike is heavily loaded all the time (I'm a 300lb guy). Sometimes I shut the bike off with the kill switch (FJR switch mod done), and other times with the key.

One thing that I haven't been able to discern with all of these posts is whether or not the bikes with hard starting issues are being shut down and started back up in the "T" or "S" mode. I do 90% of my riding in the "T" mode and the bike is alway shut down in "T" mode. I will switch between the two while out riding, but always switch back to "T" mode when I enter the neighborhood. I don't know why I do this, I just do.

I have no idea if this has any bearing on the issue or not. I know it shouldn't make a difference, but when I switch between the two there is a definite difference between the two both audibly and by feel. I'm sure the injector pressure goes up and the timing advances more in "S" thus being a potential contributor, but have no basis for this. This is mearly a suggestion for a possible cause.

::021::

 

[markjenn]

so another question why do some suffer from it and other dont ?

If we knew the cause, then we'd perhaps know this answer. But there is also a statistical distribution going on - even if every bike had the same exact chance of a hard start, there are going to be some who never experience the problem, and some who have it happen multiple times. For example, if the odds of a hard start are 1 in 1000 and everybody started their bike 1000 times, then about 37% of riders would never have the problem, 37% would have the problem once, 18% twice, 6% three times, etc. Given the size of a forum like this, some poor soul on here would probably have the problem five or more times.

In fact, the odds are not equal for all bikes. Trip length is a big factor as some riders use their bikes often for short trips and while others use the bike only for long-distance touring, so some will have a lot more chances for a hard start. And we have some data that there are other factors involved. But regardless, there is very much a random element that will cause some bikes to have the issue big time and others not at all just by virtue of the roll of the die.

- Mark

 

[markjenn]

I'm sure the injector pressure goes up and the timing advances more in "S" thus being a potential contributor, but have no basis for this. This is mearly a suggestion for a possible cause.

Since riding mode is preserved between engine starts, it is remotely possible that starting in one mode or the other is worse for the hard start. Since the vast majority of riders keep the bike in S model nearly all the time we do know that the bike does have occasional hard starts in S model; the idea that starting in T mode solves the hard start issue is an intriguing one. I'm skeptical, but you never know for sure without data. I'd be interested if there are other riders who consistently start the bike in T and have had a hard start.

For the record, I don't think we have any evidence that the S and T modes changes ignition timing or fuel pressure. (Most FI systems are designed to run at a constant fuel pressure - mixture tuning is affected by the length of time the injectors inject fuel, not fuel pressure changes.) Most think the modes simply vary the throttle response curve between the twistgrip and throttle bodies and introduce more/less damping in the system.

- Mark

 

[scott123007]

Since riding mode is preserved between engine starts, it is remotely possible that starting in one mode or the other is worse for the hard start. Since the vast majority of riders keep the bike in S model nearly all the time we do know that the bike does have occasional hard starts in S model; the idea that starting in T mode solves the hard start issue is an intriguing one. I'm skeptical, but you never know for sure without data. I'd be interested if there are other riders who consistently start the bike in T and have had a hard start.

For the record, I don't think we have any evidence that the S and T modes changes ignition timing or fuel pressure. (Most FI systems are designed to run at a constant fuel pressure - mixture tuning is affected by the length of time the injectors inject fuel, not fuel pressure changes.) Most think the modes simply vary the throttle response curve between the twistgrip and throttle bodies and introduce more/less damping in the system.

- Mark

Regardless of what mode you're in, there are only two ways to start the bike. In gear, with the clutch pulled in, or in neutral, both of which "disable" for lack of a better definition, whatever drive mode you're in. So, that theory can get thrown out the window 8)

 

[yz454]

You want that answer go look at flash tune maps .

 

[markjenn]

Regardless of what mode you're in, there are only two ways to start the bike. In gear, with the clutch pulled in, or in neutral, both of which "disable" for lack of a better definition, whatever drive mode you're in. So, that theory can get thrown out the window 8)

I tend to agree, but I don't know precisely what changes between S and T... if the throttle mapping changes, perhaps the startup mixture, idle bleed air, or something else changes. Maybe whatever "bug" many of us hypothesize is in the CPU code only bites in S mode for some reason. I'm willing to keep an open mind on this, if for no other reason, that the fact we've really exhausted all the "reasonable" ideas for the hard start - there might be something going on which is very very weird and off the wall.

In another thread, I discussed how probably all the fuel trimming for baro pressure, ambient temp, etc. are probably done with lookup tables in software. It would take only one crazy value poked into these tables incorrectly to have a system that would be fine except in some combo of circumstances that might only happen one in a thousand starts. Weirder things have happened.

- Mark

 

[mcbrien]

I just had my first hard start , which took days to get it started at 30,000 miles
and the only thing I've done different was to start running regular unleaded.
I don't think that would be the cause.

 

[autoteach]

I'm sure the injector pressure goes up and the timing advances more in "S" thus being a potential contributor, but have no basis for this. This is merely a suggestion for a possible cause.

How is the fuel pressure changing?
Freguency drive?
Electronic FPR?
Vacuum FPR?
If it is one of those, bu which means is it changing the fuel pressure? Basically, explain how it works.

 

[Juan]

I've been following this thread closely and now I offer my experience. Bike is 2013 model with 16000 km (10000 miles). System is completely stock. Nearly always in T mode, except for occasional S mode, but I always revert to T mode when leaving unpaved roads. I start the bike in neutral and with clutch pulled in (habit). Mixed travel distances, some only a few kilometres, others seveal hundred kilometres at a time. Bike NEVER had a hard start.

 

[whizzerwheel]

I recently experienced the no start issue. I don't go on the forums much so I wasn't aware of a pattern issue with this at all, so I approached this just like any other no start issue I've had. I happen to be an automobile technician and have dealt with no start issues hundreds of times with cars. I recognized that it might be flooded because I would occasionally get a pop indicating there was ignition occurring at least at some level. I know about WOT clear flood mode and pretty quickly tried this but it still would not start. Came back next day and still no start even with WOT. Came back a few days later and still would not start. The battery lives on a tender and I never allowed the battery to wear down completely, but stopped when it noticeably cranked slower.

So when I had some time, I decided to pull it down and see what I could see. I pulled the tank and associated panels to get access to the plugs and then remembered that I had purchased an extended warranty, and why should I do this in a cold garage when Yamaha should be doing this? I honestly expected that I had a bad fuel pump at this point. I called AAA and had them tow it to the dealer. Got a call from the dealer a few days later and they said the plugs were fouled and I owed them $250. They've not seen this problem. Kinda pissed off at myself for not following thru and kinda pissed off at the dealer for charging me. But they may not be able to get reimbursed for warranty claims for this issue from Yamaha, so I guess that's just the way it goes. Wish I had researched this on the forum first.

Just thought I'd document this here so we can see the extent of the problem. Mines a first generation 2012.

 

[TXTenere]

I often get gas, and then ride about 1/4 mile down the way to another stop to pick up groceries. I stay parked there for about twenty minutes, and about half the time when I go to restart, it takes longer than normal to get the bike to start. I'm not sure if this is what others are calling a "hard start" or not. However, I do have questions for those who have experienced a hard start.

* When the bike is hard to start, do you let off of the starter button before trying to open the throttle, and cranking again?
* When the bike is hard to start, have you ever immediately tried to open the throttle, without stopping cranking?

Each time my bike cranks longer than about 2 seconds (which is longer than it has ever taken to start my bike, normally) I immediately open the throttle, while continuing to crank the motor. After doing so, the bike has always fired up immediately.

I'm wondering if the hard start issue would be less of an issue if riders immediately opened the throttle while continuing to crank. Has this NOT worked for anyone? I'm thinking that maybe when riders stop cranking, that exasperates the issue...

 

[Koinz]

I recently experienced the no start issue. I don't go on the forums much so I wasn't aware of a pattern issue with this at all, so I approached this just like any other no start issue I've had. I happen to be an automobile technician and have dealt with no start issues hundreds of times with cars. I recognized that it might be flooded because I would occasionally get a pop indicating there was ignition occurring at least at some level. I know about WOT clear flood mode and pretty quickly tried this but it still would not start. Came back next day and still no start even with WOT. Came back a few days later and still would not start. The battery lives on a tender and I never allowed the battery to wear down completely, but stopped when it noticeably cranked slower.

So when I had some time, I decided to pull it down and see what I could see. I pulled the tank and associated panels to get access to the plugs and then remembered that I had purchased an extended warranty, and why should I do this in a cold garage when Yamaha should be doing this? I honestly expected that I had a bad fuel pump at this point. I called AAA and had them tow it to the dealer. Got a call from the dealer a few days later and they said the plugs were fouled and I owed them $250. They've not seen this problem. Kinda pissed off at myself for not following thru and kinda pissed off at the dealer for charging me. But they may not be able to get reimbursed for warranty claims for this issue from Yamaha, so I guess that's just the way it goes. Wish I had researched this on the forum first.

Just thought I'd document this here so we can see the extent of the problem. Mines a first generation 2012.

Can't believe they charged you. Did they explain to you why the plugs were fouled and you couldn't start it with a wide open throttle while cranking. Next time, pull the FI fuse and crank it over a little to clear the condition, then replace the fuse. That usually works.

 

[JRE]

which fuse is the FI fuse?

 

[markjenn]

I often get gas, and then ride about 1/4 mile down the way to another stop to pick up groceries. I stay parked there for about twenty minutes, and about half the time when I go to restart, it takes longer than normal to get the bike to start. I'm not sure if this is what others are calling a "hard start" or not.

This doesn't sound like the "hard start" that has been discussed so much.... just a typical "warm start" or "hot start" that sometimes requires a second or two more cranking. AFAIK, the classic hard start, with the potential to leave you stranded, is always a cold start issue. (That's why there is much speculation that the issue is a too-rich startup mixture problem.) If you can consistently reproduce your "slow warm start" scenario, leave the throttle closed for a few more seconds next time.... I bet the bike will start fine.

The typical MO of a hard start is that one cranks a cold engine with the throttle closed (as you're supposed to) and the bike either never fires, or it fires briefly and then never fires again without intervention with WOT, fuse pulling, waiting a long time, etc. In this scenario, the rider will typically start the WOT process with a new cranking session rather than rolling to WOT from closed throttle while cranking. The important thing appears to be to go to WOT as soon as you recognize the issue, whether you stop cranking or continue cranking when you go to WOT probably doesn't matter. But I'm waving my arms here.... I haven't tried it.

- Mark

 

[big dave]

which fuse is the FI fuse?

Page 85 in owner manual (6.29)

4th fuse down, left hand side

 

[JRE]

Thanks...my manual still hasn't arrived.

 

[whizzerwheel]

Can't believe they charged you. Did they explain to you why the plugs were fouled and you couldn't start it with a wide open throttle while cranking. Next time, pull the FI fuse and crank it over a little to clear the condition, then replace the fuse. That usually works.

Yah, they charged me. They didn't explain why it happened, or even that it was something they've ever seen. I'm embarrassed. In their defense...this is a multi-line dealer and I don't think they see many Tenere's even though they supposedly sell them.
I question the need to pull the FI fuse if WOT actually works. WOT should shut off any fuel to the injectors. I suspect that pulling the fuse is simply a coincidence if it starts...but I'm not positive WOT is recognized as clear flood mode in the Tenere. Does anybody know this as a fact?

Anyways thanks for the positive responses. Up to my neck in snow and waiting for spring...