Throttle Position Sensor TPS Part Number

[ARKNT]

Hopefully you are on the good side of mil code issues. This is a pretty long thread, how long have you been having issues with it?
I had never heard of using shear bolts till you brought it up. I guess it may prevent misajustment from someone like me.

Brad

 

[Macka]

Well Mark, so far so good! That extra couple of "points" may be all that is needed to overcome the MIL issue on the NT.
A couple of good long rides free of codes will give us confirmation that my suspicion of a too high threshold figure in the ECU might be the cause of this common problem.
Keep us posted!

Macka

 

[ToddTool]

Hey Brad,

Yeah, this has been a tough one. I now have over a hundred miles with no mils and with the data system removed. Only time will tell.

I don’t remember exactly when it started but I ordered the replacement TPS and MAP sensors in July of 2016.


Hey Macka,

I wish I had more info about the actual failure but for now I just want to ride. I do plan to examine my old TPS in more detail. It didn’t appear to have any issues but that sudden drop on the new sensor while riding, of about 0.15v below the idle setting for a full 3 seconds is yet unexplained. A worn or dirty pot would explain it, and adjusting it beyond that spot would “fix” it for a while. I do agree with you that the lower failure threshold should have been maybe 0.25v or the TPS idle setting should have been 0.60v to 0.65v as a best first guess. I hope someone else tries the adjustment with good results soon.

I’ll keep y’all posted.

Mark

 

[ToddTool]

Well, this is difficult to write but mil 8 is back. At almost exactly 150 miles after removing the data system I noticed a very subtle surging while cruising. I looked at the dash but no mil. A couple of curves and shifts later, the mil 8 was back. I stopped, powered off and it reset but came right back. My wife was with me and we were about 10 miles from home so I reset it again and made sure to never let the throttle close all the way and that kept the mil light off. However, the bike did not like to be rev’d up with the clutch pulled in at low speeds. It would surge like my lawn mower as it is running out of gas and if I did close the throttle while it was doing that then the bike would die. I assume these are symptoms you described Macka, if the idle rpm is raised too high.

I still have plenty of ideas but I’m losing enthusiasm.

Mark

 

[dnktng]

Well, this is difficult to write but mil 8 is back. At almost exactly 150 miles after removing the data system I noticed a very subtle surging while cruising. I looked at the dash but no mil. A couple of curves and shifts later, the mil 8 was back. I stopped, powered off and it reset but came right back. My wife was with me and we were about 10 miles from home so I reset it again and made sure to never let the throttle close all the way and that kept the mil light off. However, the bike did not like to be rev’d up with the clutch pulled in at low speeds. It would surge like my lawn mower as it is running out of gas and if I did close the throttle while it was doing that then the bike would die. I assume these are symptoms you described Macka, if the idle rpm is raised too high.

I still have plenty of ideas but I’m losing enthusiasm.

Mark

ECM>ECM Connector>wiring>10 Pin Connector>wiring>TPS connector>TPS. What hasn't been checked/replaced/cleaned?

$90 for a used ECM. This would eliminate the ECM and 1/2 of the ECM connector. If it proves your ECM was good maybe Don would like to try it for a while.

 

[Macka]

Well, this is difficult to write but mil 8 is back. At almost exactly 150 miles after removing the data system I noticed a very subtle surging while cruising. I looked at the dash but no mil. A couple of curves and shifts later, the mil 8 was back. I stopped, powered off and it reset but came right back. My wife was with me and we were about 10 miles from home so I reset it again and made sure to never let the throttle close all the way and that kept the mil light off. However, the bike did not like to be rev’d up with the clutch pulled in at low speeds. It would surge like my lawn mower as it is running out of gas and if I did close the throttle while it was doing that then the bike would die. I assume these are symptoms you described Macka, if the idle rpm is raised too high.

I still have plenty of ideas but I’m losing enthusiasm.

Mark

That is very frustrating for you and me as well as others who are following this saga!
I understand your waning enthusiasm and at the moment I have few further ideas.
On the subject of "surging" at cruise, mine has always done that at light/coasting throttle at 80-110 kph. I believe that it is normal to a degree due to a lean mixture.
Is this surge new to you and do you feel it is not fuel related as mine is?
I wonder if just possibly this time you had a HIGH TPS voltage fault instead of LOW?
That would explain the low rev "hunting" and stalling.
Check in "workshop" mode for the actual TPS fault, HIGH or LOW and let us know.

Macka

 

[ToddTool]

Yes, I have noticed the surging before and it is quite annoying but I was hoping it was a symptom because I noticed nothing bad for that first 150 miles. It may be that I was just enjoying riding and ignored it.

Yesterday I rode the bike in limp mode to the Honda dealer in the neighboring town and they slipped me in just to read the error code. It only showed Voltage Low for the TPS and the guy said nothing else looked out of kilter. There was a lot of info on the laptop screen and I wish I had taken a picture.

Some evening this week I plan to strip off the Tupperware again and bypass the TPS wiring with a seperate cable.

And thanks Dan, I have been overlooking the 10 pin connector.

Mark

 

[Macka]

That is frustrating.
Where to from here
By "by-pass the wiring" do you mean substitute a harness between the TPS and ECU?

Macka

 

[ToddTool]

Yep. I will cut all three wires at the TPS leaving enough length to terminate them in a tiny male aerospace connector. The mating connector will be attached to a cable that will run toward the ECU. Since I have not seen any issues with the +5 or return and since they power other sensors, I will leave them connected to the ECU and Honda harness at the ECU connector but run a pigtail from them to connect them to a female connector that will mate to a male connector on the new ECU to TPS cable. I will cut the TPS wiper/ECU input wire near the ECU and connect the ECU input to the same female connector on the new TPS wiper pin.

If later I decide to excite the TPS with the seperate power supply, as I did before, I can do it at the ECU area and not have to get back to the TPS again.

Mark

 

[Macka]

That "sounds like a plan" as we say down here.
Good luck.

Macka

 

[ToddTool]

Well, so far so good again. I bought a mating connector to the tps and built a new cable and ran it to the ecu. I cut the tps wiper wire about an inch from from the back of the harness connector and terminated the connector end into a small female aerospace connector. I tapped into the 5v excitation and the return wires and connected them into the female connector also. I terminated the new tps cable into a male mate and mated them.

I rode the bike for about ten miles and it ran very rough, would not idle and did the lerching thing but it never errored out. I then inserted a 1.81kOhm resistor in-line with the excitation to force the idle voltage down (0.525v). That did the trick. It idled properly and ran ok at higher rpms and also didn’t error out.

The resistor was only to see if a lower idle voltage would help and since it did, I removed it, stripped off the tupperware and readjusted the tps to 0.50V at idle.

I’ve now ridden over 160 miles with no mil 8 lights so keep your fingers crossed.
Mark

 

[ARKNT]

Mark good luck. You should have kept track of your hours working on this issue and then paid yourself at the dealer rate. It would be a fine bonus.
Hopefully it will be time for you to get some long test rides in with no codes.
If this does not fix it is the ECU the next logical step? It seems about all that is left.

Brad

 

[Macka]

Mark.
I was just thinking yesterday that it was overtime since we last heard from you.
I wish you luck. It will be a stroke of genius on your part if this solves the problem.
In my mind though, I am not confident that it will, but I hope that I am wrong.
I am leaning towards an uncooperative ECU.

Macka

 

[ToddTool]

Hey Brad,
A bonus would be nice. I could buy those new tires I need.

I made a breakout cable to insert between the two aerospace connectors. I used it to temporarily put the resistor in series with the excitation. If the mil comes back I’ll use the breakout cable to insert a voltage follower (an amplifier with a gain of one) in series with the wiper/ecu input. I’ll connect my data system to both sides of the follower and try to capture the anomoly. If it is originating on the tps side I will see the voltage drop on both sides of the follower. If the ecu is pulling the signal down then it will only show on the ecu side.

If it shows only on the ecu side then I will replace the ecu. If it shows on both sides and the excitation is stable then I may replace the tps sensor with an encoder (I already have one picked out).

Hey Macka,
I’m not confident that this is resolved either but I am getting to ride some.
Mark

 

[ToddTool]

Over 200 miles and all is well.

Mark

 

[Macka]

Over 200 miles and all is well.

Mark

Thanks for the update.
I have been waiting for it but it is still early days yet.

Macka

 

[ARKNT]

I'll keep my fingers crossed but not while riding, too hard to shift that way.

Brad

 

[ToddTool]

Five hundred miles and no issues. I’ve decided that the only way to get it to raise it’s ugly head is to taunt it by declaring victory. So I’m declaring it “fixed”!

Now let’s see what happens.

Mark

 

[Phil Tarman]

NOW you've done it!!!!

Seriously, I hope not...it would be so nice to have it fixed.

 

[ToddTool]

Thanks Phil.

Does anybody know of anyone else presently having MIL 8 errors?

Mark