What now? (bad idle and poor running)

Journeyman

"And this one is just right" ~ Goldilocks
Joined
Aug 13, 2017
Messages
2,101
Location
Old Fort, NC 28762 USA
Ride
2020 3R
The bike was running great then yesterday it started stalling, has trouble idling, and runs like crapp. All coil wires are tight, vacuum hoses and caps good, primary TPS replaced 14,000 miles ago, fuel filter 14,000 miles ago. Runs better at higher RPMs, but not right. It's my main ride- I'd sure appreciate advice.

Seems like it's fighting for fuel (but 90% of fuel problems are electrical, right?) or doesn't know where the throttle is (TPS?). Hoping one of you gurus might pick up a clue from the short-poorly produced ride-around-the block video below....

 
Acts like the TPS is out again. Check with scan tool or TuneEcu.
 
im assuming you have a stepper motor, the only time i had this issue of stalling i took my stepper motor off and ive never had this problem again, im not a guru but still wanted to share just in a million in a 1 chance thats the problem because i love you ;) Neville, i read keeps them in a bin of some sort, something about toss it in there. i dunno know, good luck bud, find it quick and be safe in them hills
 
The only way to truly "see" a bad tps is with a oscilloscope. And even then it can be hard to catch it acting up. Did you shim the new one when you installed it.
 
im assuming you have a stepper motor, the only time i had this issue of stalling i took my stepper motor off and ive never had this problem again, im not a guru but still wanted to share just in a million in a 1 chance thats the problem because i love you ;) Neville, i read keeps them in a bin of some sort, something about toss it in there. i dunno know, good luck bud, find it quick and be safe in them hills
The only way to truly "see" a bad tps is with a oscilloscope. And even then it can be hard to catch it acting up. Did you shim the new one when you installed it.

I'll add the stepper to the list. At least that would be a free fix.

I don't recall shimming the TPS, but may have. I've done a lot of work on this bike since then. I'll check to see. I vaguely remember something about that to keep it from sticking- is that right? Update- yeah, I'm pretty sure I did that. I just reread the posts on it.
 
Last edited:
Ok it gave you problems recently and while diagnosing it you found a vacuum leak on at least 1 port on number 3 tb. . That being said I'm going to assume you changed all the port caps so you know they're good. Plus you verified the large vacuum hose to the map sensor it fine. As for the stepper motor it doesn't make much sense in the recording it looks like your twisting it alot further just to get it to run then the stepper motor would be. Have you done a ISCV check it like doing a reset only you just checking the voltage points. And then clicking to the next. As long as soon as you verify the second voltage point TAB the page to the page with the map and it will stop the reset. I'd check them and while yoir down there plugging things is check each plug on each fuel injector to make sure all three are plagged in and latched. Would want any of them to rattle and send weird signals to the injectors. Oh and yes you can assume that I proved that can happen. Mucking around all them vacuum ports :) just thinking out loud :D
 
Ok it gave you problems recently and while diagnosing it you found a vacuum leak on at least 1 port on number 3 tb. . That being said I'm going to assume you changed all the port caps so you know they're good. Plus you verified the large vacuum hose to the map sensor it fine. As for the stepper motor it doesn't make much sense in the recording it looks like your twisting it alot further just to get it to run then the stepper motor would be. Have you done a ISCV check it like doing a reset only you just checking the voltage points. And then clicking to the next. As long as soon as you verify the second voltage point TAB the page to the page with the map and it will stop the reset. I'd check them and while yoir down there plugging things is check each plug on each fuel injector to make sure all three are plagged in and latched. Would want any of them to rattle and send weird signals to the injectors. Oh and yes you can assume that I proved that can happen. Mucking around all them vacuum ports :) just thinking out loud :D

I did the ISCV check and it's within tolerance. I replaced the Map sensor hose yesterday (only one I didn't replace before), but no difference.

I'll check those injector connections!

I just fixed my left heater grip and installed Flip's saddlebag inserts. I'm nice to her- don't know why she want to treat me this way...
 
I guess if it is missing at idle u might take a thermal gun and find the cylender that is not firing good then u could consintrate on that cyl for hoses coils injectors ect
 
Normally, I'd do one thing at a time and check results, but I had to get to work, so I just "went medieval" (pliers, no blow torch) this morning. WD-40ed the heck out of the throttle body and step motor linkages, unplugged and re-plugged numerous wires under the tank, crimped all the coil wires (again), pulled and inspected the vacuum hoses, and disconnected the battery for about 30 minutes. Held my breath and fired her up. Idled well! Blipped the throttle- kept running! Suited up, headed for work and hoped for the best.

Well, I wish I knew what it was, but it is now running better than ever- no, like better than ever! I've had a miss in third or fourth around 4800 at WOT, that I thought I needed to tune out- gone now! I need to double check, but I think the thump I've been feeling cruising at 3K is also gone.

Almost to work and had to see (for science!).... yep, a very light quick throttle in first brought the front right up- and tall!!! She's baaack.....

Been temperamental lately, so we'll see, but for now the world is right again!

 
Back
Top