04 hesitating, stalling in VERY hot weather

[gbasky]

I posted on this topic earlier, but a recent 5000km trip through AB and BC added more detail to my earlier description of problem:

- Problem seems limited to riding in hot weather (>30 degrees Celsius)

- Hesitating/bogging down doesn't happen at constant speed, cruising at highway speed

- Hesitating seems to start when rolling on/off throttle - e.g., in curves, or stop and go riding when passing through a town

- When it's hesitating, I have to keep revs up to prevent stalling

- At one point, bike actually stalled while I was riding at city speed.

Yamaha dealership in Vernon BC spent an hour, but couldn't determine reason for problem; they said they tested the fuel pump and it was fine.

I'm not mechanical (the extent of my wrenching so far has been limited to oil changes and changing bulbs). But at the same time, I'm not thrilled with the idea of handing my local dealer the bike and a blank cheque, with instructions to spend as much time as they like diagnosing and fixing the problem.

What does this sound like? Is this something I could investigate myself? If not, where should I ask dealer techs to focus their time/attention?

Greg Basky

Saskatoon SK

CANADA

 

[Ignacio]

What's the idle speed set to when it's hot?

 

[RossKean]

+1

Also, is the fuel tank venting properly? i.e. Do you find the tank is developing either positive pressure or negative pressure? You can tell when you open the gas cap.

 

[RadioHowie]

As to the Topic Title "...VERY hot weather" I immediately looked at your profile to determine your location...

Saskatoon -- VERY hot weather???

C'mon...you're joking, right??

signed,

Sunny, Hot & >105degrees for the 5th consecutive week in Central Florida

 

[wfooshee]

Idle speed would be an issue if it stalled at idle, but I think he's describing just rolling on the throttle to accelerate. Maybe it's at 3 grand, give it gas and it stumbles.

Tank venting could affect fuel delivery, but I would think that would affect ALL fuel delivery and would eventually affect constant running as well.

Gen-I bikes have constant fuel flow and return unused fuel to the tank, so the pump is basically always running while any amount of fuel is flowing, unless it's really really slow. In other words, fuel pressure should always be there, and a throttle opening shouldn't suck the system dry instantly. Still, it would be worth knowing what the fuel pressure is in the fuel rail.....

And I second 'Howie's notions on the definition of "hot." Hell, my house hits mid-80s (>30) INSIDE with the A/C running!

[Mocking whiney voice] ">30 degrees Celsius... it's REALLY hot!!!!!" [/Mocking whiney voice]

I'm sure some southwest folks have something to say about it, too.

But seriously, see if you can get the fuel pressure measured in the fuel rail, while it's under load.

 

[Hornet Pilot]

Does the bike have a Power Commander installed?

 

[Mihalis fjr]

Sounds like a defective TPS...

Mine had similar symptoms before the recall,especially in hot weather at about 35 C.

In the test where the dealer did the defective unit worked perfectly,but in the hot of the engine the problem was there.

With the new unit the problem solved.Somewhere i have read that the problem in a defective TPS deteriorates in the hot..

 

[gbasky]

Sounds like a defective TPS...

Mine had similar symptoms before the recall,especially in hot weather at about 35 C.

In the test where the dealer did the defective unit worked perfectly,but in the hot of the engine the problem was there.

With the new unit the problem solved.Somewhere i have read that the problem in a defective TPS deteriorates in the hot..

thanks for note

How long ago did you have your TPS replaced?

Does it make sense that this problem would just start rearing its head last fall (Sept 2014) in my 2004 bike with (then) 70,000kms on it (when recall was issued in '06)?

 

[gbasky]

Idle speed would be an issue if it stalled at idle, but I think he's describing just rolling on the throttle to accelerate. Maybe it's at 3 grand, give it gas and it stumbles.
Tank venting could affect fuel delivery, but I would think that would affect ALL fuel delivery and would eventually affect constant running as well.

Gen-I bikes have constant fuel flow and return unused fuel to the tank, so the pump is basically always running while any amount of fuel is flowing, unless it's really really slow. In other words, fuel pressure should always be there, and a throttle opening shouldn't suck the system dry instantly. Still, it would be worth knowing what the fuel pressure is in the fuel rail.....

And I second 'Howie's notions on the definition of "hot." Hell, my house hits mid-80s (>30) INSIDE with the A/C running!

[Mocking whiney voice] ">30 degrees Celsius... it's REALLY hot!!!!!" [/Mocking whiney voice]

I'm sure some southwest folks have something to say about it, too.

But seriously, see if you can get the fuel pressure measured in the fuel rail, while it's under load.

Funny that you should ask that.

Cuz tank was pressurizing in the hot weather - such that every time I unlocked the cap, it let out a burst or exhale.

When Vernon dealership was investigating, they pulled off gas tank, and said the routing for the vent lines looked "funny"

So they rerouted those, which seemed to fix that part of the problem. No more pressure build up in tank.

As for "hot" it's true we don't get crazy hot like you folks in southern states.

+1
Also, is the fuel tank venting properly? i.e. Do you find the tank is developing either positive pressure or negative pressure? You can tell when you open the gas cap.

Funny that you should ask that.

Cuz tank was pressurizing in the hot weather - such that every time I unlocked the cap, it let out a burst or exhale.

When Vernon dealership was investigating, they pulled off gas tank, and said the routing for the vent lines looked "funny"

So they rerouted those, which seemed to fix that part of the problem. No more pressure build up in tank.

As for "hot" it's true we don't get crazy hot like you folks in southern states.

 

[RossKean]

Is it safe to say that the tank isn't running under negative pressure after they re-routed the lines? If it is pulling a vacuum as fuel is used up, you could run into reduced fuel flow and possible tank collapse. This can happen if the check valve in the gas cap is gummed up.

Edit: Very much worthwhile to check out the TPS.

 

[Mihalis fjr]

Sounds like a defective TPS...

Mine had similar symptoms before the recall,especially in hot weather at about 35 C.

In the test where the dealer did the defective unit worked perfectly,but in the hot of the engine the problem was there.

With the new unit the problem solved.Somewhere i have read that the problem in a defective TPS deteriorates in the hot..

thanks for note

How long ago did you have your TPS replaced?

Does it make sense that this problem would just start rearing its head last fall (Sept 2014) in my 2004 bike with (then) 70,000kms on it (when recall was issued in '06)?

I did it in 2006 if i remember well,at about 40,000 kms.I have not any problem all these years.My fjr is a 2003/abs European model.Is the same with the 2004 US model.

 

[DeSudet]

I'm leaning toward an air or vacuum leak. Sure, it's not a moto engine, but my cage behaved the same way when there was a crack in one of the intake hoses. Change the throttle too quickly either way and it would bog down or stall. Idled fine and maintained RPMs ok. I'd check between the filter and engine as well as the PAIR system (assuming that hasn't been capped off).

Starter fluid is an old school trick for identifying a leak. With the engine running, just spray a little around the hoses you're checking and if the engine revs, the starter fluid worked it's way in through a leak where you were just spraying.

Alternatively, you can use a scrap of garden hose held to your ear and move the other end around to listen for any sucking/hissing where it doesn't belong. Good luck!

Very carefully NOT commenting on the 'VERY hot' weather...

 

[gbasky]

Sounds like a defective TPS...

Mine had similar symptoms before the recall,especially in hot weather at about 35 C.

In the test where the dealer did the defective unit worked perfectly,but in the hot of the engine the problem was there.

With the new unit the problem solved.Somewhere i have read that the problem in a defective TPS deteriorates in the hot..

thanks for note

How long ago did you have your TPS replaced?

Does it make sense that this problem would just start rearing its head last fall (Sept 2014) in my 2004 bike with (then) 70,000kms on it (when recall was issued in '06)?

I did it in 2006 if i remember well,at about 40,000 kms.I have not any problem all these years.My fjr is a 2003/abs European model.Is the same with the 2004 US model.

Thanks a bunch FJR Commander

I contacted Yamaha Canada with my VIN yesterday - they confirmed that my bike is indeed part of the recall.

I have an appointment with my local dealership to have TPS replaced next week.

Will keep my fingers crossed that this fixes the problem.

Greg

 

[ionbeam]

This is a repost of something I wrote in days past:

Last fall I had one hot running incident that caused me to shorten up a ride with HERJR (12/3/12 -- now Iris on the Forum) because of bucking and lack of throttle response, after that episode it ran just fine. Early this spring I had another episode of buck/fart/misfire. About 6 weeks ago Feejer started to regularly be unpleasant when hot, exhibiting misfiring at some cruising speeds. Starting a few weeks ago it would sometimes become intolerant of slight throttle openings at idle. The symptoms occurred when very hot, > 3bars and radiator fan cycling on/off.

After a bad ride I checked the diAG screen but there were no codes set. I checked the values of all the sensors including the TPS and found nothing wrong. I was concerned about the delay between the misfiring and when I checked the TPS. Next time I experienced misfiring I pulled over and immediately shut down and invoked the diAG screen. Every thing was within spec. After restarting bikie it ran well. Next time it happened I shut off the key while going ~35 mph and entered diAG and ran tests while coasting down and found nothing out of spec.

Wellhell, time to get serious. This past weekend I pulled off the filler ring assembly (procedure here) and found an amazing pile of road spooge that I cleaned out. I dissembled the ring and verified all vent passages were clear (1). I checked all hoses under the gas tank for pinching and obstruction. No problems found. A test ride quickly showed no cure. No surprise.

It becomes a bit more tricky to troubleshoot when everything passes the diAG test because those are the operating values that the ECU makes its calculations from. I did a bit of studying with the FSM and came up with a list of things to check.

Among the sensors, the TPS, atmospheric pressure sensor (here after APS) and intake manifold pressure sensor (IPS) were high on the suspect list. The pressure sensors include a integrated circuit (IC) that performs temperature compensation and linearization of signals. ICs don't tolerate heat well so they became suspects. Both atmosphere and intake sensors are the exact same part(!). I pulled them and verified that the sensor opening was not obstructed. DO NOT POKE ANYTHING IN THE SENSOR HOLE! DO NOT SQUIRT AN AEROSOL SPRAY IN THE HOLE! The active part of the sensor is very delicate. The APS operates over a very small range so it is unlikely to be a problem, the IPS has a wide dynamic range and it also bakes under the tank making it a likely suspect. Since the sensors are the same I swapped them to see if the problem was either cured or changed. A test ride quickly showed no change, no cure.

Next --- > I used my fuel pressure gauge and mity-vac to test the fuel pressure regulator. No problem. At least at room temperature. I put a Tee on the intake manifold vacuum line that controls the fuel pressure regulator, ran a vacuum line up to the dash and put on a vacuum gauge. Ride time. Upon misfire it was clear that the change in manifold vacuum was a consequence of the misfire and not a leading cause (2). This pretty much lets out the fuel injectors, fuel pump and pressure regulator. This is the first time that I started to really consider that the problem might be electrical ignition.

Next --- > Even though the TPS has worked in all previous testing I couldn't rule it out. At this point I had a faint recollection that the problem suddenly became worse after taking all the play out of the throttle cable. Hmmm... I pulled the connector, checked voltages, ohmed the unit at ambient temps and cleaned the filthy sensor. All normal. I back-probed the connector, ran wires up to the dash and Velcroed my cheapie DMM to the dash and went for a ride with Good Pillion™ installed (3). Three bars, fan cycled on, 35 mph BUCK, FART, MISFIRE. Whoa baby, did you see what the DMM showed?!?! Next glitch, DMM showed a major TPS drop-out. By this point I note that the drop-outs always occur between .775 and .778 volts. I could ride anyplace around that particular range and had no problems. Deliberate operation in that range caused TPS drop out and the beginnings of Pillion hammering on my helmet to stop doing that. Back in the driveway I checked my light throttle problem at idle and it was plain to see the TPS drop out. As soon as everything cooled a bit the TPS worked normally again.

911 -- Hello University Motors -- Gary please --

The TPS is held on by two screws, one screw hole is round and the other is slotted to allow TPS adjustment. Refer to the FSM for the procedure. The screws are vertically aligned -- one above the other. Issue 1, why did Yamaha have use security torques screws here? Issue 2, the lower screw access is mostly blocked by the frame. There is ~1/2 inch of space for the torques bit. It's looking like either the intake comes off or the engine comes out to access the screw. First I will try some tool fabrication, I think I can get the little bugger out. [edited 7/26: Both screw holes are oval, both screws have to be loose to adjust the TPS.]


(1) Should anyone consider dissembling the gas cap assembly farther, be aware that there are 4 small springs and a check ball that are fabricated with AllaKhazam's fourth dimensional vanishing capabilities. If you take out the three screws that hold the lock assembly in place take great care not to let AllaKhazam disappear your parts.

(2) Intake manifold pressure runs around 12 inches/Hg. At WOT it drops to ~2 inches. This test also made my FJR run different due to more vacuum volume and a bit of 'shock absorber' effect from the diaphragm of the vacuum gauge. My particular FJR has always taken 3-4 spins of the crank before it fired up. With the hose/gauge connected it fired instantly! Also, it had much smoother throttle response. I will spend some more time looking into this after everything else is sorted out. This shows some potential....

(3) It was gosh darn educational watching the TPS while riding. Idle was .620 volts. I tend to cruise at .770 to .790 volts almost all the time which is most likely why the TPS is worn out in that range. I discovered that I actually move the throttle quite a lot but the amount is so small that I don't notice my hand physically doing it. To avoid the death zone at .775 volts I rode in a higher gear than I normally would. I noticed that at 35 mph in a lower gear the TPS read .720 volts but at the same speed in a high gear the TPS read .850 to 1.100 volts. This means that the engine was over geared and it took much more throttle to maintain speed. Said another way, fuel economy sucks when doing that!

See how to replace the TPS here.

Judging from the number of failures of the Throttle Position Sensor I believe we can now rename it Total Piece of Shit.

These are the three primary parts to the TPS.

Attention to all you throttle spring releasers, the left side spring serves two functions. It is tightly wound to provide return spring tension for the throttle body shaft and ensures that the two pickup brushes (wipers) are firmly in contact with the resistors.

The center item is the actual body of the TPS. The black trails are resistive material screened onto the inert white backing. The far left terminal is Ground, the far right terminal is +5 volts from the ECU, the terminal just to the left of +5 is the signal terminal going back to the ECU. As the wipers slide along the resistor trails a varying voltage that is proportional to the throttle position gets returned to the ECU.

The right side object has the two pick up brushes, one riding on the +5 volt resistor and the other riding on the signal resistor. On my TPS the resistor that goes +5 volts to ground is 5.28k ohms and the resistor going to the signal terminal is <100 ohms.

These are the two wipers that ride along the resistive material. They are made up of individual wires. Note the wiper on the right side, at the very right edge, has one wire bent out. The wipers themselves have strong spring tension which is then supplemented by the large holding spring.

The arrows in the above picture show where the wipers sit at idle.

This is the source of the problem with the TPS. Normally, resistive material is carbon mixed with silica then fired to make a very hard glass like resistor. The TPS resistive material is made of a softer plastic type product. The wipers individual wires actually have cut clear thorough the resistive material. When viewed under a microscope the base material is visible in the bottom of the grooves. Normally, this type of resistive material has its value determined based on it being a 'sheet', once cut the value will start to change. I measured a few of the furrows and they are just a bit wider than the wiper wires so there isn't sure contact side to side and the bottom is worn through. Additionally, and most importantly, the thinned material is no longer resistively stable under thermal changes. In particular, once it hits some critical temperature it goes from resistive to non-resistive. Said inversely, it goes from somewhat conductive to not conductive at all in those furrowed areas. This is one reason that a TPS can pass test at room temperature but fail once the engine heats up.

The arrows point out where the brushes have worn away the resistive material at idle and at roughly 25-30% throttle. For me that is around 3k RPM. You can also see that it has started to burn in the highly worn places.

The TPS I put in has a new P/N that is the same on the '06 so I take that to mean there has been some kind of a change to the part. It will take time or an autopsy of the '06 part to find out if it has been improved. I will note that my mostly solved surging is now back with the new TPS. I don't yet know if that is coincidence or related. My engine now runs with abrupt throttle response like the '06 people are reporting.

 

[Canadian FJR]

I looked but can't find the procedcure on how to check your sensor from the screen. You need to do a specific sequence and then observe the readings as you roll the throttle open and observing that there are no numbers skipped.

Found it: https://www.fjrforum.com/forum/index.php?showtopic=9612

Canadian FJR

 

[ionbeam]

^^^^^ Hidden in all the words in my previous post is the fact that the diAG procedure doesn't always show the TPS problem, even when the engine is hot. I was one of the lucky ones to be a leader in having TPS problems and the only way I could diagnose my problem was by riding with a multimeter connected to the TPS so I could watch the voltage as I rode. I tried every which-way to see the problem with diAG but in the end, using the DMM while riding was the only way I could see it fail.

 

[Mihalis fjr]

Thanks a bunch FJR Commander

I contacted Yamaha Canada with my VIN yesterday - they confirmed that my bike is indeed part of the recall.

I have an appointment with my local dealership to have TPS replaced next week.

Will keep my fingers crossed that this fixes the problem.

Greg

Please let us know if the new TPS fixes the problem.