Hesitation at 3500 rpms

Help Please. My 2003 FJR just started hesitating while cruising and/or accelerating. At first I thought it was gunked up fuel injectors or maybe bad gas. I added fuel injector cleaner. Same problem. I synced the throttle bodies. Same problem. I cleaned the wiring harness contacts. Same Problem. Now I'm getting ready to install new Spark Plugs. The plugs that are in there now are NGX Iridium’s and only have 7,000 miles on them. Just to rule out the plugs I'm going to install new ones. The bike starts fine, but when running on the road it will intermittently chug at either cruising or accelerating. It appears to show the problem in 3rd gear. Any ideas are appreciated.

Mine pulses (chugs?) some times, but I'm not sure if I notice it more in 3rd gear or not. I never considered it an issue, though.

Has the TPS been changed on the recall???????????? If not get it done.

FJRay said:

Has the TPS been changed on the recall???????????? If not get it done.

Click to expand...

THE TPS HAS BEEN CHANGED BASED ON THE RECALL

candymon said:

FJRay said:

Has the TPS been changed on the recall???????????? If not get it done.

Click to expand...

THE TPS HAS BEEN CHANGED BASED ON THE RECALL

Click to expand...

Is it possible to have a spark plug go bad at a short interval?

candymon said:

Is it possible to have a spark plug go bad at a short interval?

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A poorly seated spark plug boot is a more likely culprit.

Also, though unlikely unless the bike's been sitting a long time, you might wanna take a flashlight and take a good long look in your tank for any rust.

After all, it IS going on 7 years old and the tank as-is from the factory is NOT rust treated, plus it is a very mild steel, susceptible to ethanol-induced moisture collection.

The fuel pump only has a very rudimentary filtering system and crud/crap/spooge/rust in your tank can and will clog up the pump input strainer, causing you all kinds of grief and head scratching attempting to solve a problem with poor-running. Same crud/crap/spooge/rust will also ruin your fuel pump if left unabated. And they ain't cheap.

DAMHIK

'howie

3500 rpm is in that sweet area that the FJR seems to run the best at. There should be no hick-ups or chugging happening there.

Even though you had the TPS replaced it is still possible that the new one is causing the problem. However, that would not be gear dependent. It should (could, would) happen at the same spot in each gear. Best bet would be to do the diagnostic checks for the TPS recall to see if the voltage is changing in a nice linear fashion.

Hope it's something simple like a loose spark plug cap or somesuch.

Does it do it at 3.5k rpm in all gears or just 3rd gear?

If it is just 3rd gear you could be looking at a transmission problem.

If it happens at 3.5k rpm in every gear, even if the roughness is just minor in some gears you are most likely looking at a sensor or a control system. The much maligned TPS comes to mind first because it is so tightly linked to engine speed. I see you had the sensor changed, hopefully it was replaced with the new design sensor and not another old one.

If your '03 experiences roughness at different rpm points in all the gears, we will need to have another round of 50 questions to narrow down common events.

Fred W said:

3500 rpm is in that sweet area that the FJR seems to run the best at. There should be no hick-ups or chugging happening there.
Even though you had the TPS replaced it is still possible that the new one is causing the problem. However, that would not be gear dependent. It should (could, would) happen at the same spot in each gear. Best bet would be to do the diagnostic checks for the TPS recall to see if the voltage is changing in a nice linear fashion.

Hope it's something simple like a loose spark plug cap or somesuch.

Click to expand...

I placed the order yesterday for 4 new Iridium NGK's. Just want to rule it out. Is there a fuel filter on this bike? If so I'd like to change that too. The bikes in a garage the whole time except for this past winter when we were in the midst of a home remodel and did'nt have a garage. Now it's back in. The hesistation does not seem to be specific to one gear. I did reseat all the spark plug boots a week ago, and filled them up with dielectric grease. I also did the diagnostic on the TPS and the number moves linearly from 17 to 100 without any jearkiness. If there is a fuel filter, I'd like to change it. Can you please tell me where it is.

What about TBS also?

Between TPS, plugs, and TBS they could all possibly contribute. Although seems strange at 3500RPM.

FJRBluesman said:

What about TBS also?
Between TPS, plugs, and TBS they could all possibly contribute. Although seems strange at 3500RPM.

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Also did a TBS using my homemade monometer. I've got 1,2 & 4 at the same level of 3. However, I've never checked the actual vacuum on #3. I just use it as my reference to sync with 1,2 & 4.

check all the electrical plugs/connections under the tank

problems have been found in the past and the older the bike, the more suseptable (sic) it's gonna be

candymon said:

I placed the order yesterday for 4 new Iridium NGK's. Just want to rule it out. Is there a fuel filter on this bike? If so I'd like to change that too. The bikes in a garage the whole time except for this past winter when we were in the midst of a home remodel and did'nt have a garage. Now it's back in. The hesistation does not seem to be specific to one gear. I did reseat all the spark plug boots a week ago, and filled them up with dielectric grease. I also did the diagnostic on the TPS and the number moves linearly from 17 to 100 without any jearkiness. If there is a fuel filter, I'd like to change it. Can you please tell me where it is.

Click to expand...

No filter per se. Just a pickup screen in the tank. Not likely that, unless you have a butt load of rusty crap in there like Howie.

Since you already covered the easy stuff, let's hope for the plugs...

By the way, you coulda just jammed in some non iridiums from the parts store. I never use iridiums.

Fred W said:

candymon said:

I placed the order yesterday for 4 new Iridium NGK's. Just want to rule it out. Is there a fuel filter on this bike? If so I'd like to change that too. The bikes in a garage the whole time except for this past winter when we were in the midst of a home remodel and did'nt have a garage. Now it's back in. The hesistation does not seem to be specific to one gear. I did reseat all the spark plug boots a week ago, and filled them up with dielectric grease. I also did the diagnostic on the TPS and the number moves linearly from 17 to 100 without any jearkiness. If there is a fuel filter, I'd like to change it. Can you please tell me where it is.

Click to expand...

No filter per se. Just a pickup screen in the tank. Not likely that, unless you have a butt load of rusty crap in there like Howie.

Since you already covered the easy stuff, let's hope for the plugs...

By the way, you coulda just jammed in some non iridiums from the parts store. I never use iridiums.

Click to expand...

I don't mind spending a little extra for the bike to run at its best. When I switched from standard to iridium, I did notice an improvement in performance. I did check only one of the electrical connections under the tank and found a little oxidation which I cleaned and then filled the connnector with dielectric grease. When I do the spark plug change, I'll check all of them and seal with the dielectric grease. I'm looking at all available options when I go under the tank for hopefully the last time this season.

I did check only one of the electrical connections under the tank and found a little oxidation which I cleaned and then filled the connnector with dielectric grease. When I do the spark plug change, I'll check all of them and seal with the dielectric grease.

Here's the link to the connector you really need to check. I didn't get any RPM-specific issues like you have (that screams TPS to me, BTW), but it sure smoothed out my motor at all RPMs when I finally dislodged the corrosion in here - Took several attempts:

https://www.fjrforum.com/forum//index.php?s...p;hl=hiyosilver

Good luck.

candymon said:

I don't mind spending a little extra for the bike to run at its best. When I switched from standard to iridium, I did notice an improvement in performance.

Click to expand...

Any performance improvement youi noticed had to be due to your having just replaced your old plugs (or placebo effect). There is nothing about iridium plugs that would "improve engine performance" compared to a new set of properly gapped standards plugs. They are only supposed to last longer. They are supposed to last twice as long (at twice the price). That's still a good deal if you don't want to be changing plugs.

Personally, I don't mind changing the plugs more often since I do my own work and will be under the tank anyways for other maintenance. Y plug MMV

Fred W said:

candymon said:

I don't mind spending a little extra for the bike to run at its best. When I switched from standard to iridium, I did notice an improvement in performance.

Click to expand...

Any performance improvement youi noticed had to be due to your having just replaced your old plugs (or placebo effect). There is nothing about iridium plugs that would "improve engine performance" compared to a new set of properly gapped standards plugs. They are only supposed to last longer. They are supposed to last twice as long (at twice the price). That's still a good deal if you don't want to be changing plugs.

Personally, I don't mind changing the plugs more often since I do my own work and will be under the tank anyways for other maintenance. Y plug MMV

Click to expand...

I noticed with the Iridiums that they are pre-gaped to .032" and you can't change the gap without harming the Iridium Electrode. The specs call for a gap of .028 to .030. Is it a problem putting in the Iridiums which have a gap of .032".

candymon said:

Fred W said:

candymon said:

I don't mind spending a little extra for the bike to run at its best. When I switched from standard to iridium, I did notice an improvement in performance.

Click to expand...

Any performance improvement youi noticed had to be due to your having just replaced your old plugs (or placebo effect). There is nothing about iridium plugs that would "improve engine performance" compared to a new set of properly gapped standards plugs. They are only supposed to last longer. They are supposed to last twice as long (at twice the price). That's still a good deal if you don't want to be changing plugs.

Personally, I don't mind changing the plugs more often since I do my own work and will be under the tank anyways for other maintenance. Y plug MMV

Click to expand...

I noticed with the Iridiums that they are pre-gaped to .032" and you can't change the gap without harming the Iridium Electrode. The specs call for a gap of .028 to .030. Is it a problem putting in the Iridiums which have a gap of .032".

Click to expand...

I just put them in, but many others (without touching the center electrode) do check the gap and carefully adjust

Patriot said:

candymon said:

Fred W said:

candymon said:

I don't mind spending a little extra for the bike to run at its best. When I switched from standard to iridium, I did notice an improvement in performance.

Click to expand...

Any performance improvement youi noticed had to be due to your having just replaced your old plugs (or placebo effect). There is nothing about iridium plugs that would "improve engine performance" compared to a new set of properly gapped standards plugs. They are only supposed to last longer. They are supposed to last twice as long (at twice the price). That's still a good deal if you don't want to be changing plugs.

Personally, I don't mind changing the plugs more often since I do my own work and will be under the tank anyways for other maintenance. Y plug MMV

Click to expand...

I noticed with the Iridiums that they are pre-gaped to .032" and you can't change the gap without harming the Iridium Electrode. The specs call for a gap of .028 to .030. Is it a problem putting in the Iridiums which have a gap of .032".

Click to expand...

I just put them in, but many others (without touching the center electrode) do check the gap and carefully adjust

Click to expand...

I'll do the same and just put them in. Thanks for your input!