Throttle position sensor

Ratman · Oct 21, 2005

A little help please, Im looking for a link to help me get and read the error codes. It appears I may have a problem with the throttle position sensor. The dealer said he checked them and there was no errors but am still having problems with it surging. It's worse when its hot out, although we are done with that in Minnesota.

Thanks all.

Glen

Purveyor of correct opinions and advice since 1954.

C&C · Oct 21, 2005

I don't want to assume anything but before you go looking for a problem with the TPS have you done your throttle body synchronization?

ionbeam · Oct 21, 2005

The dealer said he checked them and there was no errors but am still having problems with it surging.

The dealer will have tested the TPS per the manual which simply says read the TPS and idle and full throttle. This only checks for a catastrophic failure. You need to check the area of the sensor inbetween these two positions.

[SIZE=14pt]Checking the TPS Sensor[/SIZE]

This test is done using the Diagnostic screen. How to:

With the key off, press and hold the "Select" and "Reset" buttons simultaneously and turn the key on (do not start, just ON), continue to hold the buttons until the display next to the fuel gauge says diAG (5-10 seconds).

Release the two buttons. Now, press the "Select" and "Reset" buttons simultaneously again. After ~ 2 seconds the display should show d1:01 on top and a two digit number at the bottom. You are now looking at the throttle position sensor (TPS) output. The TPS value is the two digits at the bottom of the display.

Turning the throttle will change the digits. Normal is 15-17 with the throttle closed and 97 to 100 with the throttle wide open. When the TPS goes bad it can be catastrophic, where the two digit value is just plain wrong and doesn't follow the throttle at all. This could be the TPS, it could be in the harness that connects to the TPS or it could be the ECU.

The other failure mode of the TPS is to have 'dead spots' as the throttle is opened. This is the most common failure and it usually occurs at roughly 20-40% of throttle opening because that is range where the throttle is positioned for most riding. To check this -- very, very slowly open the throttle from full closed to full open and observe that the numbers climb with no skipped numbers and no drop-out readings (e.g. 45, 46, 47, 01, 01, 48, 49) The 01 reading is a 'drop-out'. This failure is almost certainly the TPS.

To leave the diAG mode simply turn the key off. Done.

Alan

sparky3008 · Oct 21, 2005

I don't want to assume anything but before you go looking for a problem with the TPS have you done your throttle body synchronization?

Surging is a common issue on the fjr and probably many fuel injected inline 4's.

As C&C mentioned I would definitely start with syching the TB before looking at the TPS. Next many have used the Power Commander and custom maps to help eliminate normal stock lean issue's and surging.

ionbeam · Oct 21, 2005

Ratman didn't give a full description of his problem. Basically, when cruising around 3k rpm his engine feels like it quits running for a fraction of a second then abruptly starts again with rude consequences for the rider.

Abrupt changes are usually electrical in nature. Typically this kind of symptom would have you looking at the ignition and main power sources. In this case it is strongly associated with a narrow RPM range. This makes it more likely to be sensor based than a loose connection. The TPS is the most likely culprit as it has a proven record as being unreliable and often fails with this kind of symptom. I think Ratman's FJR has ~27k miles so this is likely. If a careful test of the TPS shows no problem then it is time to look at the FP regulator. If the ECU sees a sensor such as air temp or intake pressure go out of range it should set a code and use a default value. The rider probably wouldn't even notice. Ratman's service shop found no codes.

Before we go off the deep end we need to find out the results of Ratman's TPS testing.

Alan

sparky3008 · Oct 21, 2005

Oh that sounds dangerous.

Ratman · Oct 25, 2005

Thanks all, I’ve been riding must of the week end so I haven’t been on line, Thanks again Alan, we hooked up earlier. I now have just under 30K on her. I’ve had some problems all summer but wouldn’t off it long enough to really check it out. The worst one was I dug about three foot trench on some new pavement right in front of the roller operator. I will be going through the tests. Where did you find this info out?? Is it in the shop manual??

ionbeam · Oct 25, 2005

Most of the TPS test procedure is from the shop manual, the balance is from life 101. The specifications are straight from the manual. I've been there, done that and I hope to have clarified the procedure from the Factory Service Manual procedure a bit. The FSM doesn't say to watch the diAG screen for irregular readings while slowly opening the throttle. I have enough experience with pot 'n wiper fed Analog to Digital converters to know to check the full range.

The TPS test should take you way less than 30 minutes including a cigarette and coffee break :lol:

Alan

*Pot 'n wiper: The ECU feeds a potentiometer a fixed reference voltage, the wiper moves along the length of the resistor as the throttle moves, this causes the wiper voltage to change with throttle position. The analog (varying) voltage gets converted to digital (on/off; 0/1) to be digestible by the ECU.

ahamlin01 · Oct 25, 2005

I posted a while back on the surging issue, and have had a lot of good results (i.e. improvement) by following the steps suggested by the members of this forum.

If you want a description of what my FJR surging was like, click here

my experience with surging

So I was very interested in this post - I have not taken the bike to the dealer - but I followed these directions exactly and saw NO skips, or errors, when very very slowly turning the throttle from 15 to 100 on the gauge. The bike was stone cold. This week-end when I am out, I can make the bike surge at will (by running at ~4000-4500 rpm in 3rd gear for a while, comfortable back-road speeds, and then shifting up to 5th and continuing at about 2300 rpm - it will definitely surge) - so, when the bike is nice and hot, and I make it surge, I will pull over and do the test again. I am wondering if I will then see the drop-outs in the numbers you are talking about.

I will re-post and let you know what I find - I will also be looking for your experiences for comparison. All I know so far is that 87 octane helped a lot - and if I stay in the 4000 rpm range it does not seem to get into the surging - I can also make the surging go away by bringing the bike back to a lower gear and "clearing it" out by getting up into the 6000 rpm range briefly.

Dumb question - how much does it cost to get the TPS replaced? I am going to assume that I cannot do that myself without a lot of special equipment? Any ideas?

Allen

ahamlin01 · Oct 31, 2005

I was out for a couple hundred mile ride yesterday and the bike started surging really badly. I stopped, turned it off, and went into the diag mode listed to check the TPS - what I found:

min was 15 - max was 98

first time rolling the throttle up slowly -

15,16,17,18,19,20,21,21,22

17,18,19,20,21,22 <-- jumped down to 17/18 then rolled up to about 22/23

17,18,19,20,21,22 <-- jumped down to 17/18 again then rolled all the way to 98 smoothly with no drop-outs

So, I guess I have seen what the drop-outs look like? Seemed in-correct anyway.

Any thoughts from anyone more technical than me?

Thanks

Allen

ionbeam · Nov 2, 2005

17,18,19,20,21,22 <-- jumped down to 17/18 again then rolled all the way to 98 smoothly with no drop-outs

[SIZE=14pt]Now that's just not right![/SIZE]

Sounds like it's time for a TPS transplant.

Alan

ahamlin01 · Nov 4, 2005

Thanks - I didn't think so.

Any idea at all what is involved? Cost? Time?

Thanks

Allen

ionbeam · Nov 4, 2005

The TPS is item #20, held on by two screws, located at the cyl. #4 end of the TB rack. I can't remember if it is Phillips like the Fuel Pressure Regulator. If it is Phillips it will be a bit of a bother to get them out without buggering the screw head. You may want to order a couple of screws.

Item 20 is p/n 5PS-85885-00-00 depending on your shopping determination the part is typically $125 to $130. The screws are p/n 8CC-14216-10-00

The bare bones: Raise tank. Remove screws. Unplug and remove TPS. Replace with new TPS, screw in loosely, plug-in. Verify diAG sees 16-99 or so. Tighten the two screws. Lower and attach tank. Ride. Enjoy.

Alan

Bounce · Nov 4, 2005

This week-end when I am out, I can make the bike surge at will (by running at ~4000-4500 rpm in 3rd gear for a while, comfortable back-road speeds, and then shifting up to 5th and continuing at about 2300 rpm - it will definitely surge) - so, when the bike is nice and hot, and I make it surge, I will pull over and do the test again. I am wondering if I will then see the drop-outs in the numbers you are talking about.

One thing to consider (one possibility - in cases when the TPS test doesn't show anything wrong):

The "no load" 2500-3000 rpm surge is pretty common and has been attributed to the quirks of the EFI mapping. Some have suggested that the bike is right at the cusp between 2 parts of the map so that it's jumping back and forth between them at that range (when under no/low load).

If down shifting or accellerating out of that range resolves the problem, then look at the TBS and either the dash-enabled CO setting changes often called the Barbarian Jumper Mod.

A more eleborate mod is to install a Power Commander 3 and remap the EFI with any of the various maps available for the FJR.

ionbeam · Nov 4, 2005

There are two co-mingled surgers here. ahamlin01 sounds like the standard factory installed surge but Ratman, who is mixed in this thread has a definite problem.

Ratman's problems started on the EZB :haha: and migrated to this Forum. This is Ratman's symptom

Geeze, linking to EZB, watch my warning rating skyrocket now :lol:

Alan

radman · Nov 4, 2005

Best warning I could come up with on such short notice.........

ahamlin01 · Nov 4, 2005

Thanks for the directions - and the approx pricing - it looks like something I would be very comfortable doing myself. I appreciate the insight and the assistance.

Allen

Fabone · Nov 5, 2005

The TPS is item #20, held on by two screws, located at the cyl. #4 end of the TB rack. I can't remember if it is Phillips like the Fuel Pressure Regulator. If it is Phillips it will be a bit of a bother to get them out without buggering the screw head. You may want to order a couple of screws.

On mine, the screws were tamperproof Torx and a PITA to get out, because of the clearance. You're in for a treat. :butcher:

RTSR1/FJR · Mar 12, 2006

I think mine developed a TPS problem Friday. On our way to Daytona, we were cruising at approx. 3500-4000rpm and the thing does a hiccup of sorts and repeats it a few times. I drop a couple of gears and roll through it. Almost like a misfire. It clears up after that though. Again yesterday, we're going back up to Daytona and it does it again, only now we're on I-95. This time it's at 4500rpm. I just accellerate through it and it disappears again, so I'm thinking TPS now. It never returned after each event after rolling through it. I'll be doing a test on it today.

Throttle position sensor

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