Accelerator Position Sensor (APS) Adjustment

[texscottyd]

23 hours ago, peteinpa said:

I'm still not quite happy after my ECU flash on my 15 after several rides.

Checked my current settings and have:  14:  17 and 102      15:   16 and 99

With them so high I should get it really smooth when done dropping to the 10 and 12 #'s..

Guess I'll rip it apart again for the umpteenth million time. 😡

I had the same experience with my 2015 FJ:  The ECU reflash alone was a huge improvement, but when I finally got around to adjusting the APS, that was the missing link.  It’s nice and smooth with on/off throttle transitions, and I ride it 100% in A-mode now.  

You mention 10 or 12 for the low numbers, but I didn’t go nearly that far.  Here are the adjustment notes from my files: 

[peteinpa]

👍I'll be ripping it apart in an hour. With some here doing it twice to get lower #s I'll go for as low as I can keeping it in the parameters.

[texscottyd]

57 minutes ago, peteinpa said:

👍I'll be ripping it apart in an hour. With some here doing it twice to get lower #s I'll go for as low as I can keeping it in the parameters.

Good luck!   While you’re wrenching, I’m riding...  far too nice of day to not be out enjoying it on the FJ. 

[peteinpa]

Done. now 14 reads  13 and 98                                    15 reads  12 and 96

Low as it can go keeping all #s in range.

Just lift rear of tank, prop it, and a regular 1/4 inch drive ratchet with 8mm socket works.

 

[peteinpa]

Just got back from a ride. WOW! This is the missing piece of the puzzle!

It now rides like the throttle is a rheostat.  Perfectly smooth, no jerking, even shifts better. Now acts like a carbed bike perfectly jetted. 2WDW flash is great, lots of power, but the APS adjustment makes it perfect.

Thanks  Piotrek!

[2and3cylinders]

On 4/25/2021 at 2:07 PM, peteinpa said:

Done. now 14 reads  13 and 98                                    15 reads  12 and 96

Low as it can go keeping all #s in range.

Just lift rear of tank, prop it, and a regular 1/4 inch drive ratchet with 8mm socket works.

 

I did it so long ago, I'll have to look in my notes and procedure cheat sheets.  What "ranges" are you adhering to?

I can check TB sync without touching the tank because I installed hoses to the ports that I pull out and connect to my meter, so I only need to remove the bodywork and tank to change the air filter and check the valves.  I even change the spark plugs by only tipping the radiator.

 But next time I have to lift the tank I'll recheck the APS and fine tune TB sync.

[peteinpa]

9 hours ago, 2and3cylinders said:

I did it so long ago, I'll have to look in my notes and procedure cheat sheets.  What "ranges" are you adhering to?

I can check TB sync without touching the tank because I installed hoses to the ports that I pull out and connect to my meter, so I only need to remove the bodywork and tank to change the air filter and check the valves.  I even change the spark plugs by only tipping the radiator.

 But next time I have to lift the tank I'll recheck the APS and fine tune TB sync.

There is a high and low range listed in the manual for diag. 14 and 15. For smoothness you want the numbers as low as possible.

I thought about going lower than what's in the manual but didn't.

[texscottyd]

1 hour ago, peteinpa said:

There is a high and low range listed in the manual for diag. 14 and 15.

The original post by @piotrek included a table with the reference ranges for both open and closed readings for Diag 14 and 15.   I've just copied it to here...   it's that 'Range' column for each of the four settings that you want to stay within.  

[fj09newbie]

so on my 2017, I don't think I can get into DIag mode to to get what my current settings are.  am I missing something?  I have tried the instructions listed about pushing the TCS and Reset buttons, turning on, and pushing 8-10 seconds.  no Diag comes up.  Anyone have any ideas I haven't found yet?

[texscottyd]

Hi @fj09newbie - Unfortunately that diagnostic menu is only available on the 2015 & 2016 FJ models… starting with 2017, those functions are locked down and only dealer accessible.    

There are patch cables available to clear and read the OBD codes with a standard code scanner, but I don’t think that would grant you access to update the APS settings.  

[bwringer]

Just another satisfied customer reporting in...

The original owner had the ECU flashed, but my 2015 was still pretty herky-jerky. By all accounts far better than the "death trap" tuning it apparently left the factory with, but still pretty annoying and un-ideal.

So despite all my pre and post purchase FJ-09 research, I had never even heard of the APS adjustment until a few days ago. I made the adjustment yesterday, and after a few test rides in between rain squalls, including a trip to roundabout-land just to my north...

I'd say... it's about 50% better.

Still not anywhere near as smooth as a well set up carbureted bike, but it's better. I would not describe it as "electric motor" or "seamless", but for the price of $0 plus a little time and effort, I'm very happy with the improvement.

It's very noticeable when plonking along a highway at a steady 55-70mph at very low throttle openings. MUUUUCH smoother and far less overshooting and undershooting as you make those teensy automatic throttle adjustments to maintain a steady speed.

For transitions from closed throttle (for example, when leaned over in a roundabout and picking up the throttle again in second gear), it certainly is a lot better but I was hoping for more improvement. The bike still requires more attention than others in low-speed and tight cornering where you want a buttery-smooth transition from engine braking and idle to applying power. 

Overall, I'm very pleased, and every 15-16 FJ-09 owner should run to the garage and check their Diag. 14 and 15 numbers today.

 

My numbers, FWIW:

Diag 14:
Stock: 17, 101
Adjusted: 13, 97
(Allowed range: 12-22, 97-107)

Diag 15:
Stock: 17, 101
Adjusted: 12, 96
(Allowed range: 10-24, 95-109)

I think I got this as low as I could.

As ever, the biggest pain in the ass when working on this bike is dealing with the Tupperware. It's not hard or all that time-consuming once you've been through it a time or twelve, but it's just tedious, ya know?  At least Yamaha had the wisdom to use 1/4 turn fasteners in many places.

Anyway, with the tank swiveled up and propped up with a random chunk of wood, it was easy to reach the sensor for twiddling.

I also REALLY appreciate the fact that this adjustment can be made with the engine cold and not running. On Suzuki V-Stroms, there's a very similar and extremely crucial Throttle Position Sensor adjustment that has to be made with the engine at full temp and running. Plus, they install it with security Torx screws, buried behind scalding hot coolant hoses, so you have to rip half the bike to even get to these. I replaced mine with allen head screws so I could juuuuuuuuuuust barely reach them from the side of the bike with a really long 4mm ball-end. Oh, and the adjustments are subatomic; I mean, Ant-Man would overshoot just by breathing, and if you accidentally move the sensor by 0.5mm the bike stalls...

Anyway, yeah, this was pretty dang easy by comparison.

As far as reaching that well-buried forward bolt, I used this miniature 1/4" ratchet and an extra-low-profile 8mm socket. Both the wee ratchet and the set of low-profile sockets were found at O'Reilly Auto Parts, which sells all sorts of interesting oddball tools like this. The sockets have an external 7/16" hex on them, so that's a 7/16" ratcheting wrench back there for an even lower-profile solution if needed. Anyway, the teensy ratchet and low-profile socket worked perfectly for both bolts, and my regular 8mm socket would not have fit.

 

Edited October 24, 2021 by bwringer

[peteinpa]

So I always run in STD mode and find it to be perfect.  I'm puzzled why you feel only 50% improvement. 

Are you sure it's flashed?  Did you  ride north of 114 MPH?

The only other thing affecting smoothness is a TB sync.

[bwringer]

I'd say it's pretty darn good now, but not in the absolutely creamy, buttery-smooth territory of a well set-up carbureted bike in the 0% to 0.5% to 2% throttle range; that super-thin "wedge" that lets you safely get back into the power sooner.

I've ridden several, and I don't think any fuel-injected bike can achieve that.

This is all subjective as hell, yes... perhaps my standards are too lofty. I'd say the Triumph Tiger 800, for example, is about the best in this regard among the FI bikes I've tried, and in bone-stock form it's still a fair bit better than my FJ with the flash, APS, etc. Neither comes close to my 1983 GS850G.

The PO told me it was flashed, and the accurate speedo leads me to believe that he wasn't lying about it. I have not cracked 114MPH; I don't think that's wise with hard luggage mounted. And of course someone monkeyed with the ECU retainer, even though the air filter was original.

And yes, I synced the TBs to be spot-on using my Carbtune Pro about 5,000 miles ago when I did the valve check. I've synced carbs a zillion times, so syncing TBs is easy-peasy. I don't think that's a problem.

Power and weight enter into the smoothness equation as well; my GS850G has about 40-45 horsepower less, and weighs around 125-150 pounds more, both of which serve to blunt any abruptness. My KLR weighs roughly the same as the FJ, but has about 1/3 the power. 

Is it now "good enough" so that this is no longer a concern or annoyance? Sure.

Is it in the same ballpark as old-skool CV carbs (especially on heavier and/or less powerful bikes)? Nope.

Edited October 25, 2021 by bwringer

[peteinpa]

one other detractor for me is use of 90 octane no ethanol unless on a ride when I need to fill up.

Bike weight does mask bad fueling and this is a light bike.

My only other FI bike was an ST1300.  Too much weight. Main reason I left it for my FJ-09.

[dazzler24]

17 hours ago, bwringer said:

I'd say it's pretty darn good now, but not in the absolutely creamy, buttery-smooth territory of a well set-up carbureted bike in the 0% to 0.5% to 2% throttle range; that super-thin "wedge" that lets you safely get back into the power sooner.

I've ridden several, and I don't think any fuel-injected bike can achieve that.

This is all subjective as hell, yes... perhaps my standards are too lofty. I'd say the Triumph Tiger 800, for example, is about the best in this regard among the FI bikes I've tried, and in bone-stock form it's still a fair bit better than my FJ with the flash, APS, etc. Neither comes close to my 1983 GS850G.

The PO told me it was flashed, and the accurate speedo leads me to believe that he wasn't lying about it. I have not cracked 114MPH; I don't think that's wise with hard luggage mounted. And of course someone monkeyed with the ECU retainer, even though the air filter was original.

And yes, I synced the TBs to be spot-on using my Carbtune Pro about 5,000 miles ago when I did the valve check. I've synced carbs a zillion times, so syncing TBs is easy-peasy. I don't think that's a problem.

Power and weight enter into the smoothness equation as well; my GS850G has about 40-45 horsepower less, and weighs around 125-150 pounds more, both of which serve to blunt any abruptness. My KLR weighs roughly the same as the FJ, but has about 1/3 the power. 

Is it now "good enough" so that this is no longer a concern or annoyance? Sure.

Is it in the same ballpark as old-skool CV carbs (especially on heavier and/or less powerful bikes)? Nope.

To get a few more % points of twitchiness out of the first ~1/3rd of throttle opening have you considered either replacing the OEM throttle with a 'cammed' throttle or doing a mod on your OEM throttle with a small drill bit/ file to achieve the same effect?

I did this to mine years ago and had almost forgotten about it until this discussion popped up.

If you haven't heard of it, the procedure is to groove the throttle cable guide from the end of the cable (where it attaches to the throttle) for about a third of the circumference of the guide.  Tapering the groove slowly up to re-join with the existing level of the guide.

The idea is to get a logarithmic throttle rather than a linear one. i.e., throttle has to turn further at the start for a given increase in revs then becomes linear - compared to the stock setup.  Hope that makes sense.

Here's some pictures that probably explain it better than my fumbling words did.  These are not of the Tracer/FJ but you get the idea.