QuikSilver
Member
If you have an EFI surging problem or experience occasional stalling coming off idle, this information may be of interest to you.
Back in March, I reported a very intermittent problem to this forum. It occurred every few thousand miles over the first 37,000 miles on my '03 FJR. It would occasionally stall and run rough when coming off of idle. I also had occasional EFI surging and lurching when tooling around parking lots at ~ 2000 RPM and when at low throttle settings under light load (like going 60 - 70 MPH down a modest grade). Things were definitely worse when the engine and outside temperature were hot. Finally, the stalling problem started to occur more frequently. With very concerted attempts to find the dead spot coming off idle, I could demonstrate the symptom to my dealer after 10 - 15 minutes of trying.
I suspected a bad throttle position sensor for the stalling coming off of idle problem and attributed the occasional surging and lurching as being a quirk of the Yamaha EFI system (certainly something I thought that could be fixed by a Power Commander, but I am too cheap for that). My dealer thought it was due to improperly balanced throttlebodies (butterfly openings and throttle body synch). They balanced the throttle bodies but there was no change. (I wasn't surprised as I had just done a throttle body synch and replaced the air filter and plugs).
I found the shop manual diagnostics for testing the throttle position sensor (TPS) rather confusing (as did my dealer). Luckily, Ionbeam came to my rescue with the information in this link
https://www.fjrforum.com/forum//index.php?showtopic=3283&hl.
Following his expert instructions, within 30 seconds I had clear evidence that I had a bad throttle position sensor. Coming off of a closed throttle, the diagnostic readout was 15. While giving the throttle a very slow twist, the diagnostic readout increased to 17 then became very erratic and would jump around, like 14, 2, 9, 15, 8, 0,..., then it returned to a very linearly increasing response from 17 up to 100 at full throttle. It was very repeatable.
The dealership thanked me for showing them how to test the TPS and replaced it under the Y.E.S. program (my only claim, $125 parts, 1 hour labor).
Bottom line is the FJR once again runs like a champ! I would say better than I ever remember. I did 1200 miles in the mountains of Eastern AZ and Western NM last weekend. Not a hint of stalling, and to my amazement, the occasional surging and lurching under light load were absolutely gone! Mileage was 46+ MPG when averaging 80 - 90 MPH on one 325 mile section of tight and interestng sweepers.
So ... if you have some suspicious EFI issues, check your throttle position sensor!
Thanks Ionbeam! I owe you one.
QuilSilver
Ride Hard. You can rest when you die!
Back in March, I reported a very intermittent problem to this forum. It occurred every few thousand miles over the first 37,000 miles on my '03 FJR. It would occasionally stall and run rough when coming off of idle. I also had occasional EFI surging and lurching when tooling around parking lots at ~ 2000 RPM and when at low throttle settings under light load (like going 60 - 70 MPH down a modest grade). Things were definitely worse when the engine and outside temperature were hot. Finally, the stalling problem started to occur more frequently. With very concerted attempts to find the dead spot coming off idle, I could demonstrate the symptom to my dealer after 10 - 15 minutes of trying.
I suspected a bad throttle position sensor for the stalling coming off of idle problem and attributed the occasional surging and lurching as being a quirk of the Yamaha EFI system (certainly something I thought that could be fixed by a Power Commander, but I am too cheap for that). My dealer thought it was due to improperly balanced throttlebodies (butterfly openings and throttle body synch). They balanced the throttle bodies but there was no change. (I wasn't surprised as I had just done a throttle body synch and replaced the air filter and plugs).
I found the shop manual diagnostics for testing the throttle position sensor (TPS) rather confusing (as did my dealer). Luckily, Ionbeam came to my rescue with the information in this link
https://www.fjrforum.com/forum//index.php?showtopic=3283&hl.
Following his expert instructions, within 30 seconds I had clear evidence that I had a bad throttle position sensor. Coming off of a closed throttle, the diagnostic readout was 15. While giving the throttle a very slow twist, the diagnostic readout increased to 17 then became very erratic and would jump around, like 14, 2, 9, 15, 8, 0,..., then it returned to a very linearly increasing response from 17 up to 100 at full throttle. It was very repeatable.
The dealership thanked me for showing them how to test the TPS and replaced it under the Y.E.S. program (my only claim, $125 parts, 1 hour labor).
Bottom line is the FJR once again runs like a champ! I would say better than I ever remember. I did 1200 miles in the mountains of Eastern AZ and Western NM last weekend. Not a hint of stalling, and to my amazement, the occasional surging and lurching under light load were absolutely gone! Mileage was 46+ MPG when averaging 80 - 90 MPH on one 325 mile section of tight and interestng sweepers.
So ... if you have some suspicious EFI issues, check your throttle position sensor!
Thanks Ionbeam! I owe you one.
QuilSilver
Ride Hard. You can rest when you die!
