Ignition or Fuel ? Missing after bike is Hot

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2003 FJR - 15,000 miles on it.

Bike runs fine when its cold, however once it gets hot, I feel a missfire or an ignition intermitten.

Usually starts after about 45 minute of riding. This miss seems to disapear when I rock on the throttle, or at higher RPM's it is not noticable.

I have poked around at various electrical connections, wonder if this could be one of my coils or possibly a fuel injector that is failing ?? anyone have any thoughts ??

I thought about just wholesale swaping out both coils to see if that makes a difference.

The other day I was riding ( very warm outside..- 85-90 deg) - the bike would not idle. I slowed to a stop, and the engine died.... I was able to start it up, rev the engine some, keep it running till I got home.

I feel like this is related to my problem noted above.

Could it be a vapor lock ? with fuel injection ?

This is a tough one to troubleshoot, due to the nature of it. :(

 

Bearly Flying

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Check your fuel tank vent hose, probably bunch of dirt and junk blocking the lower end. Lift your Gas Cap and you will see it right behind the filler neck.

 

Shinden

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The other day I was riding ( very warm outside..- 85-90 deg) - the bike would not idle. I slowed to a stop, and the engine died.... I was able to start it up, rev the engine some, keep it running till I got home.
I had a similar problem, reference; https://www.fjrforum.com/forum//index.php?showtopic=9790

I have not had the other problems you describe, however.

fjrvtx1300s

In regards to Bearly Flying's avatar, I have emailed it to a few buddies. We all agree that the message it describes should be taught seriously at the juniour high school level, it would clue a lot of young guys into one of life's sad realities, early on. :D

 
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trimmantom

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Hi tjgraves,I've had the very same problem with my 04.

Took it to the shop and they determined it was a bad side stand switch.

It was replaced and seemed to correct the problem_______ for a while because it is now doing the same thing only when i've ridden it for a while and it's real hot.One thing you might try if you're mechanically handy is to unplug the side stand switch and run a jumper on the plug to bypass the switch,which is what the mechanic did originally to diagnois the problem originally. It's very frustrating because the damn thing doesn't do this all the time and when I take it to the shop they can't seem to duplicate what the bike is doing.The last time i had it in the shop for this crap i went over there and took the bike out to ride it long enough to duplicate what it had been doing.I rode the sucker almost 200 miles and could not get it to exhibit the symptoms as you described so I took it home and have ridden it for a couple thousand miles with not much as a hiccup.Today I took it for a ride in 95 degree heat and it started bumping again like an ignition problem.I don't know know what to do with it,can't leave it in the shop for weeks and not get it fixed.

I've done the TPS test numerous times and it has come up negative every time.I'm going to replace it anyway as the bike has 30000 miles on it and see if that makes a difference.

If you get a resolution to your problem please post your solution.Good luck

 

ahamlin01

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Could it be a vapor lock ? with fuel injection ?
I asked this same question once... the answer was no, FI can't vapor lock ( I forget who answered - it is on this board someplace!)

I have been able to greatly reduce the issues I was having with this same type of symptom by keeping the bike above 4k. When it is hot though, it'll still do the same type of thing (surging). At this point I just put up with it, and it goes away fairly quickly, especially if I just open her up. Mine is an '05 with no mods

 
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All, took my FJR into a Local Yamaha Dealer in Kalispell, Montana this past week, I asked them to see if they could find anything related to this hot engine mis/hesitation/ hicup I've explained. I delivered it to them HOT, as in, riden it for about an hour. It is missing... you have to take it for a ride... see for yourself.

I asked them to sync the throttle bodies, look it over. I have new spark plugs( problem still there), they tested the tps, coils, looked at electrical connections etc. They still had no answers for me. I trailered the bike here for vacation/ work trip, and trailering back to Washington tomorrow. Dropping it off at I90 motorsports to have them dive into it on Monday. No blockage in the vent tube, cleaned around the fuel filler with a vacume, I have a new air filter, used some compressed air to blow the drain clear, no blockages. problem still exists. Idle is set at 1000 RPM's. I am frustrated... BMW dealer is my next stop after this one.... trade it off as is... If I cannot resolve...

baaa humbug.... stay tuned... Tim

 

HIGHLANDER

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As it's died while running it should have thrown a code into the computer memory. Have you or the dealer gone into the diagnostic mode and found any codes? I'm leaning towards a bad TPS, this problem has come up a few times before on all the FJR boards. A new TPS is cheaper than a Beemer !

 

trimmantom

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Yeah that's what I thought to Highlander and I've pulled over when my bike starts it's hiccup routine and done the TPS diagnostic and it's always negative.

 

ionbeam

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Excerpted from a personal letter sent to another FJR owner with a FJR that is performing nasty when hot:

My line of work has equipped me for dealing with electronic vehicle computers and the assorted sensors that the computer depends on for feedback. I have raced my computer controlled car since '95. I have a laptop and AutoTap software that lets me into the cars computer to read *everything* and I can select up to 12 functions at a time to data log so I can look for something going out of tolerance or failing. This is what is wrong with the Yamaha ECU, there is no data port to plug into so a dealer (or an owner with enough $$$) can see what is actually going on. Major FU on Yamaha's part and they are going to pay for it when dealers shotgun troubleshoot bikes while they are under warranty.

The Yamaha ECU only has ~10 main sensors. The ECU will set codes when a sensor goes totally bad but doesn't know to set a code if the reading is only inappropriate for the conditions. Inappropriate would be like an intake air temperature reading 70 degrees when the actual air temperature is 130 degrees after drawing through the really hot air box. This would cause the ECU to map a really rich mixture. The symptoms of a wicked rich map would be intolerance of very small throttle openings, occasional misfire/stumble and perhaps stalling. This is what my 24k mile '04 has recently started doing. If I immediately pull over and check the diAG screen while it is hot, it shows all sensors reading normal. The bitch is you have to shut the key off first which I suspect resets the erroneous sensor(s). When I strip my bike down to install my new Electrosport stator (once it gets here) I'm going to look at tapping into the sensor wires of the ECU so I can read the sensor voltages pre ECU the next time I have cruddy running. I'm pretty sure my problem is caused by running too rich when hot and there are only ~5 sensors that I will need to check to verify that. I've pulled a spark plug right after one of the 'episodes' and found it to be black, another strong indicator that my operating problem is caused by running rich and the root cause will most likely be a sensor that goes flaky when hot. It is highly doubtful that there is some kind of software glitch that doesn't manifest itself until >10k miles.

My bike has been a bad surger, remediated by a PCIII. I wonder how many of the higher mileage FJRs with bad manners when hot were surgers when young...

 

rangerray

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For what it's worth, my '03 acted like this. On the highway it ran fine, but toodling around town it would miss and cut out. It would stall altogether if I didn't keep the revs up. One shop was clueless. I carried it to another where they replaced the O2 sensor. The problem was still there. They kept it a couple of more days and finally replaced the TPS. That did it! The FJR was back to normal and has done fine ever since.

Oh yea, remember: If it's got wheels or tits it's eventually gonna give you trouble.

 
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CISCO

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For what it's worth, my '03 acted like this. On the highway it ran fine, but toodling around town it would miss and cut out. It would stall altogether if I didn't keep the revs up. One shop was clueless. I carried it to another where they replaced the O2 sensor. The problem was still there. They kept it a couple of more days and finally replaced the TPS. That did it! The FJR was back to normal and has done fine ever since.
Oh yea, remember: If it's got wheels or tits it's eventually gonna give you trouble.


TPS failures do not always show up during the self DIAG mode, OR throw a code. The TPS seems to test normally, however if it is replaced the problem goes away. Ive seen this multiple times. TPS failures are intermittent and usually cause the bike to stall at idle.

 
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SOLVED!!!! NEW Throttle Position Sensor installed.... ouch... over $500, New TPS - $138, check this check that... $90 per hour shop rate. Worth it ?? I asked them to check the Throttle body sync, check out the Fuel Presure Regulator, install new TPS. After reading the posts in the forum, I could safely say from the explainations I saw - surging, like someone killing the ignition for a brief moment in time. It certainly was the problem, Just replace the TPS and I asked the shop to not spend any time troubleshooting.

Thanks Everybdy for the input on the forum!! I love you guys....!!! Sincerely, Tim

 

gasman

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Oh yea, remember: If it's got wheels or tits it's eventually gonna give you trouble.

:D

 
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