Hot start issues

jdmdohcpower

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My bike starts fine cold but Im having an issue with hot starts every so often. It just cranks. I have to pop in in 2nd and it starts right up. Any advice?

Thx
 

PosterFZ6

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Is your bike S2? Maybe from 2008?

I have the same issue. It's a major pain in the a$s.

I run K&N air filter, slip on, and power commander.

I once read a topic here where one member had a similair problem. He ran the same set up as me. What he found was the problem with his custom fueling map.

He changed the values in the first few positions to give more fuel, apparently it solved the problem.


I would like to hear what other members here have solved this issue.

PS- Thanks for the tip about starting in the second gear!:thumbup:
 

jdmdohcpower

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Its weird it just started, never did it before but its an 07. I only have Scorpion Slip on's.

2nd gear is cake, you can walk next to it. I just would like to solve the issue but Im not sure what the problem is yet.
 
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marke14

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I had and still have this problem. I may in fact be the "other forum member" that Poster is referring to above.

Here is my post from two years ago:

http://www.600riders.com/forum/fz6-...iii-fueling-problems-bike-wont-start-hot.html

I still have this issue. It did get a little better when I manually adjusted my PCIII settings on the lowest FI settings.

The WORST time to experience this is if you stall out at a traffic signal - or in slow moving traffic - on a hot day. At least once I have had to push over to the side of the road while I waited for the damn thing to cool off to the point that it would start up.

The other fun time I've had this problem is on a big group ride at a fuel stop, where everyone had to wait for me to get the god damn thing started again. This was on the ride where my current forum avatar (with officer J. Peterson) was taken from. I have since added in the extra fuel in the lower settings and it did help some as I mentioned.

My setup: U.S. model, 2007, Leo Vince slip-ons (cat eliminated), K&N air filter, PowerCommander III with the Leo Vince map from the PCIII website (with aforementioned fuel setting mods to that map).

Now even when it's hot out and I stop briefly, generally I can quickly re-start the bike. It takes a bit of feel, and timing. If it won't start, I cycle the key on and off, and try again. If it REALLY won't work after a couple of re-cycles of the ignition, I turn the key off and wait 60 seconds. It always starts after that.

Good luck, do report back if you have any further info or suggestions.

P.S. - I probably should get the thing dyno-ed and tuned properly.
 

PosterFZ6

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I had and still have this problem. I may in fact be the "other forum member" that Poster is referring to above.

Here is my post from two years ago:

http://www.600riders.com/forum/fz6-...iii-fueling-problems-bike-wont-start-hot.html

I still have this issue. It did get a little better when I manually adjusted my PCIII settings on the lowest FI settings.

The WORST time to experience this is if you stall out at a traffic signal - or in slow moving traffic - on a hot day. At least once I have had to push over to the side of the road while I waited for the damn thing to cool off to the point that it would start up.

The other fun time I've had this problem is on a big group ride at a fuel stop, where everyone had to wait for me to get the god damn thing started again. This was on the ride where my current forum avatar (with officer J. Peterson) was taken from. I have since added in the extra fuel in the lower settings and it did help some as I mentioned.

My setup: U.S. model, 2007, Leo Vince slip-ons (cat eliminated), K&N air filter, PowerCommander III with the Leo Vince map from the PCIII website (with aforementioned fuel setting mods to that map).

Now even when it's hot out and I stop briefly, generally I can quickly re-start the bike. It takes a bit of feel, and timing. If it won't start, I cycle the key on and off, and try again. If it REALLY won't work after a couple of re-cycles of the ignition, I turn the key off and wait 60 seconds. It always starts after that.

Good luck, do report back if you have any further info or suggestions.

P.S. - I probably should get the thing dyno-ed and tuned properly.

Ohh hey yeah I was talking about you.

Dude, the embarrassment as I have push my bike to the side of the road to get it to cool off is unbearable.

My procedure to restart it is same as yours, lol.

I have read quite a bit about this problem and so far no solution. everybody has so vague idea to solve this but so far I haven't found anything concrete.
 

FinalImpact

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Ohh hey yeah I was talking about you.

Dude, the embarrassment as I have push my bike to the side of the road to get it to cool off is unbearable.

My procedure to restart it is same as yours, lol.

I have read quite a bit about this problem and so far no solution. everybody has so vague idea to solve this but so far I haven't found anything concrete.


Lets get a few other to chime in as this is just an idea. . . BUT - if it RUNS perfect in every other way and you have no other complaints; we could trick the ECM for moment.
Something like this; during cold start the ECM samples the water temp and sees its cold (lets say 90F). From this it adds fuel during "cold start" which is richer than a warm start and it does so until it warms (120F).
For you, we need to mimic this and momentarily override the temperature input to the ECM so it richens the mixture. So we use a push button switch that you hold until it fires to input a fake temperature.

If anyone wants to be a Guinna pig we can work out the details. . .
 

marke14

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Ohh hey yeah I was talking about you.

...

I have read quite a bit about this problem and so far no solution. everybody has so vague idea to solve this but so far I haven't found anything concrete.

I am pretty confident that a proper tune on a dyno would fix this. It's a $300 solution though.
 

Timon

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Everyone, I know this is a very old thread, but hey it beats opening a new one up for the SAME thing.

Bike:
2008 FZ6, LeoVince Exhaust, Modified Airbox, K&N drop in filter

Anyway, now that's out of the way, here's the scenario: Ambient temperatures were about 105*F or so. The bike maintained around 190-218*F, and never got into the overheating phase. I was cruising along at about 60-85 mph on the highway with a group of people. We got off an off-ramp and pulled off to the side of the road (literally not more than a few hundred yards off the highway).

I turned the bike off, we chatted for ~3 minutes, I tried to start the bike back up and it just cranked over and over - but no go. We even tried push starting it and still nothing. I could hear the pump in the tank kick on, but the bike wouldn't turn over. Some of the guys took off and left myself and a buddy there. We pulled under an overpass into the shade and let her cool down for a bit. After reaching about 170*F, she fires right up. Seeing if she will continue to go, I let it idle and then rev up to about 6k and let off - died. Figuring it was due to the heat, I let it cool to about 158*F and tried again - same thing died after letting go at 6k.

So here's where I stand. I've had issues with hot starts taking longer before, but until the above incident it never prevented me from starting (it just took longer). The only thing I had changed recently was I had got the bike professional tuned. After researching this thread, I pulled the maps and determined that from 750 to 1500 the fuel change was 5 with the new tune, as to where the PC3 base map (410-003) for these ranges was 10 (so the tuner lowered these to 5 since they apparently didn't need to be 10).

CustomTune_zps0dd8c88a.jpg


I went ahead and adjusted the fuel change to 10 in place of all the 5's at 0% throttle. I'll report back with more details after some testing over the next few days. I'll try to test the revving issue too, but I'm doubting it is related.

If anyone else has had any luck doing other things, please let me know. I'm also looking into doing a coolant flush as well with some Engine Ice.
 
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FinalImpact

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The after market fuel controllers do NOT observe the BIKE is CRANKING and ITS HOT thus needing extra fuel to start.
** Where as the STOCK ECM adds fuel while cranking hot or cold. ***

I've never played with that software and I suspect it does not observe temperature as an input to the map table or the fact that the engine is cranking for start. That leaves you two viable options depending on how much work you wish to invest.

1) Add a circuit that sends a DC pulse to the injectors to open them. This one shot circuit open the injectors for a predefined time when the start button is pushed. Its viable, but a bit of work. The plus - no map changes.
2) add a circuit from the start switch that over rides the engine temp sender to a default value (a simple resistor) telling the ECM the engine and air are cold.

Both are possible, one is fairly easy, the other more complex but possible.

3) Or Richen the MAP at idle and live with the performance loss.
 

Timon

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So the issue isn't a Yamaha problem, but instead it's an issue on Dynojet's side of things? Wonder if they have any solutions or if we can even prove it's their system causing the problem. Has anyone tested this theory (i.e. produced the issue with the PC, removed it, and then retested under conditions as close as possible to the original test)?
 
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Fractional

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Feels cringe to resurrect this but I am experiencing the same problem on my 2009 S2, completely stock and 3k miles on the clock. It feels like it should start right up but sometimes when hot it wont start....like today.....let it cool off and it starts right up. Idk if anyone could point me somewhere where this has been discussed more? I keep coming back to this thread. Thanks!
 

lrojasma

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Any error codes? Any mods, like a fuel controller?
Feels cringe to resurrect this but I am experiencing the same problem on my 2009 S2, completely stock and 3k miles on the clock. It feels like it should start right up but sometimes when hot it wont start....like today.....let it cool off and it starts right up. Idk if anyone could point me somewhere where this has been discussed more? I keep coming back to this thread. Thanks!
I am starting to have exactly the same problem with a completely stock bike with over 80k miles on it. So it's not valve clearance.

I am thinking that could be a temperature sensor sending wrong signal to the ECU, maybe air temperature sensor? maybe map sensor, some of the sensors that connects to the ECU.

Maybe one sensor got stock at cold position so that is why we are experiencing this. IS SO ANOYING. I am scare to turn off the bike when really really hot.

I think i should find the time to check all the sensors, the problem really is that they need to be checked at cold and hot.
 
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Fuel pump is probably going.
I know it sounds irrelevant, but these are the symptoms I had when mine went.
Start fine when cold.
Run all day.
Shut down when at temperature, and try to start again 5 minutes later after a run into a store or fuel fill, and would be stuck waiting for it to cool down almost completely. Times varied depending on ambient temperature.
Down to at least 2 bars on temperature gauge and would start up and run all day again until I shut it down.
Even that was semi intermittent, as in it may do this one day and not another, it may do it one time in the day and not the next, or may do it once, not the next, but the time afterward ,,, etc.
 

lrojasma

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In my case cannot be fuel pump and i can cleary hear the pump running strong, in fact i can even see the gas on the tank splash because of the pressure.

I need more ideas...
 

Motogiro

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In my case cannot be fuel pump and i can cleary hear the pump running strong, in fact i can even see the gas on the tank splash because of the pressure.

I need more ideas...
If you have a clogged fuel filter it may be reducing fuel volume. The fuel filter is attached to the fuel pump.
 
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I was going to ask, Do you see this splashing in the tank and hear the pump running when it is not starting while warmed up?
There, I asked it.
 
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