Throttle Position Sensor TPS Part Number

hk9151 said:
I should have written that more clearly. I got the map sensor a day after I received the spark plug caps. It was the caps that fixed it. Sent the sensor back yesterday. I'm sure the caps will fix his as well, but if not I will try the map sensor next. Thanks for all the help and advice. It still blows my mind that caps would fail at such low rpm but work under a load up to redline.
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I hope that it is fixed, BUT I am not that confident yet.
I don't believe that the plug caps fit the symptoms.
As I said, I went down the same road and still eventually had to replace the MAP Sensor.
It took me three months and about 3000 km to pin it down.

Macka
 
I installed the plug caps on my Dad's NT. We put 170 miles on it so far without issue. I now have 600 miles on mine since the install. Both are running as they should. We will probably put 100 more miles on today. Time will tell. I hope its a fix, the skin on the back of my hands need healing. Again, thanks to all for the input and advice.
 
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Good to hear we could help get your bikes back on the road, pity the local Honda dealer did not know about the service bulletin for the spark plug caps.

Seagrass
 
I have been encountering the amber light the past 3 days. Last night, it blinked 8 times. Today I had Honda diagnostics run and their service technician followed the Honda book for testing and says to replace TPS sensor, but need to buy throttle assembly. Says if that doesn't work, then replace ECM (computer). I explained the TPS can be purchased seperately. He didn't offer to source it, but the guy in the parts department is going to call his buddy at Honda to get his input on the part. As far as I can tell from all the posts here, we should start with replacing the TPS and then proceed to other options if that doesn't work. The irony is, I rode for an hour this morning before taking it in for diagnostics. The light didn't come on at all.
 
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Unfortunately Honda do not assembly the throttle body, it is bought pre-assembled so Honda to not have a part number for the TPS. I did fit one sold as a Yamaha spare (from the same company as Honda) it is Yamaha part 1SL-85885-00. you will, no doubt, find the same part used on other makes and models. As it look like they are #1 maker of throttle assemblies.
I also experienced the off/on failure. It will become more frequent. Get the part as soon as you can as it will eventually leave you stranded.

Cheers,
Mark
 
Last year, or maybe two years ago, I started having the TPS error issues and the bike would go into limp mode. The shop put on the replacement plug caps and it was better for a while but didn't go away.

I read all of the posts about the TPS but wasn't convinced. I put a meter and then an oscilloscope on the TPS output looking for signs of a dirty or worn pot but it was as smooth as it could possibly be from one end to the other.

I had performed those checks with the engine stopped so I then thought that the wiper could possibly bounce at certain RPM's so I put a small capacitor across the wiper to signal ground to filter out any bounce. The problem was very prevelant just before that and this did seem to help but did not resolve it.

Now I was suspecting the MAP sensor so I order one and one of the Yamaha TPS sensors (thank you for providing that part number). It was several months before I installed them, and what a pain that was. Anyway it worked great and then the same damn thing happened again a few days later.

I was livid and just parked it for a month. Later I remembered having a similar problem with a 325 BMW car with fuel injection. That car would only run properly if I used the cheapest regular gas I could find. I aways assummed that the additives in the premium gas (especially bad with AMOCO premium with fuel injector cleaners).

I decided I had nothing to lose so I drained the premium non-alcohol gas from the tank and filled it with cheapo regular it hasn't had any issues since. It has only been about 3 or 4 tank fulls so it may rear its ugly head again but I really think its ok now. I' keep you posted.

ToddTool
 
I don't understand how a different fuel can stop TPS error codes from appearing.
Did the TPS codes disappear after it was replaced and before you changed fuels?

I am a bit confused here! :confused:

Macka
 
The error codes were never continuous. They would randomly pop up sometimes immediately after starting the engines, or after riding for a while, so disappear is not really appropriate. Anyway, after replacing the TPS and the MAP, I ran it in the garage for a while and then took it for a short ride with no errors and I hoped I had it fixed but the next weekend I went for a ride and it crapped out twice within 10 minutes. It was after that when it I changed the fuel.

It was not the error code that made me suspect the fuel, it was the sudden 1/2 second engine shutdown that almost always occured around the time that the MIL would light up. And yes, it could very well be that the error occurred first and the engine shutdown was just the ECM fail-safe limp mode kicking in. As I stated before, that BMW car exhibited the same shutdown with gas that had additives in it that are typical of premium grades such as fuel injector cleaners.

I am not convinced that the problem won't reoccur but it is working for now. If it does come back, I intend on disconnecting the 5 volt sensor excitation from the ECM to the TPS and the MAP and powering them externally from a dc-dc supply. Since both of those sensors are the only ones that get the 5 volt power from the ECM, it could be that there is an issue with that regulator circuit.

I am not trying to convince anyone of anything but I'm just sharing my experience and will let you know if it returns.

ToddTool
 
For anyone who hasn't already noticed, there is also discussion on TPS here under a thread entitled: "EFI Sensor Trouble" which gives other possible reasons a MIL Code 8 could happen [how to fix]. Thanks to y'all for posting!!!!!!
 
I suppose that "plug caps" refers to plug wires being replaced ??? or what? Don't recall hearing that term "caps" until this thread.
 
"Plug Caps" are the physical hard plastic caps (about 4" long) that connect to the spark plug lead and the spark plug.

They are removable from the spark plug lead.

Seagrass
 
I've replaced spark wires on cars before and plug caps always came with them preinstalled on the wires, so I didn't know they could be sourced separately. I wonder if this is only something done with motorcycles.
 
On most modern cars, the spark plug cap is molded to the wires.
 
Latest news: My TPS problem has reappeared this spring. I posted earlier that putting bulb grease on the connector solved it but it came back again not long afterward. It's not consistently happening. I'm supposing that because I don't ride often the "wiper" inside the TPS is not moved often enough to keep those contacts clean. So my next test is to operate the throttle off/on many times in hopes the TPS will "wake up". This, of course, is just a hunch in that the sensor seems to start working after I exercise it and try the ignition off and on a few times. I've got some tour camping coming up, sure hope it hangs in there.
 
Well, it’s back!
So its not the TPS, MAP, or gas because I have replaced them with new. I disconnected the TPS and MAP excitation from the ECM and powered them from a separate 5v supply but it did not change a thing.

While checking voltages, I had the engine running and my hand touched the alternator wires and they were very hot after only 2 or 3 minutes. A digital thermometer showed 160 deg F and rising.

I checked the coil resistances and they all read about 0.1 ohms to each other and were open to ground.

The rectifiers check good in the regulator so I put a scope on the output (picture attached, I think) its not the nice smooth ripple I expected. The SCRs switching may cause the ugliness and may be normal but I think the heat seems out of hand.

I’ve ordered a new R/R from ebay and I’ll see what happens.



View attachment 13145View attachment 13145
 
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I could not open the attachment of scope pics.
Where were the alt wires hot? Near a connector? I believe there have been issues with high resistance connections going to reg/rectifier. That could certainly cause issues.

Brad
 
ARKNT said:
I could not open the attachment of scope pics.
Where were the alt wires hot? Near a connector? I believe there have been issues with high resistance connections going to reg/rectifier. That could certainly cause issues.

Brad
Click to expand...

The wires are heating along their entire length as they would with excessive current. Has anyone else checked the wires beween the alternator and the rectifier/regulator harness for high temps?

I have since found posts of similar waveforms that are supposedly normal but I will still be swapping out the r/r and battery.
 
ToddTool said:
The wires are heating along their entire length as they would with excessive current. Has anyone else checked the wires beween the alternator and the rectifier/regulator harness for high temps?
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I started and ran the NT for 3 minutes to check Reg/Rect & wiring temps.
-My R/R heated from 65F to 82F.
-Wiring from the Alt to R/R (3 yellow) felt about the same temp as R/R.
-DC wiring out of R/R stayed cool.
For your R/R to heat up that fast...... that's some abnormal loading. The only non-stock loads I had running are a FuseBlock Relay, 5Vdc UBS power supply, GPS, and LED topbox lights.

Just some added thoughts. The ECM makes 5VDC for the TPS and MAP sensor, and I would think (not sure) it uses the same 5vdc power supply for the IAT and ECT. I would suspect (not sure) that the 5VDC is filtered and smoothed more than what the 12VDC source is supplied to the ECM. The MAP, ECT, TPS, and IAT all have hi and lo voltage fault codes, but the TPS sensor operates closer to the low volt fault than the other sensors (fault at .3vdc with idle at only .5vdc (I think)). All the others operate at mid range and are most likely less susceptible to cause a lo volt fault. But since you installed an external 5vdc to the MAP and TPS and are still getting the faults it probably isn't your TPS causing the faults. Was your external 5vdc power supply external to the NT's battery and R/R?
-I'd sort out the high temp R/R wiring first.
-Lots of wiring & connectors between the ECM and TPS.....ECM Connector, 10 pin connector near rear throttle body, TPS connector & all wiring.
-The ECM could be failing and the circuit that gives a low (or Hi) TPS volt fault could be failing and causing an erroneous fault code and forcing engine into fail-safe mode.
-Since you are pretty deep into trying to fix this, it may be worthwhile to find out if your TPS faults are Hi or Lo Volt fault. Maybe a Honda dealer would be kind enough to read if for you for something reasonable.
 
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dnktng said:
I started and ran the NT for 3 minutes to check Reg/Rect & wiring temps.
-My R/R heated from 65F to 82F.
-Wiring from the Alt to R/R (3 yellow) felt about the same temp as R/R.
-DC wiring out of R/R stayed cool.
For your R/R to heat up that fast...... that's some abnormal loading. The only non-stock loads I had running are a FuseBlock Relay, 5Vdc UBS power supply, GPS, and LED topbox lights.

Just some added thoughts. The ECM makes 5VDC for the TPS and MAP sensor, and I would think (not sure) it uses the same 5vdc power supply for the IAT and ECT. I would suspect (not sure) that the 5VDC is filtered and smoothed more than what the 12VDC source is supplied to the ECM. The MAP, ECT, TPS, and IAT all have hi and lo voltage fault codes, but the TPS sensor operates closer to the low volt fault than the other sensors (fault at .3vdc with idle at only .5vdc (I think)). All the others operate at mid range and are most likely less susceptible to cause a lo volt fault. But since you installed an external 5vdc to the MAP and TPS and are still getting the faults it probably isn't your TPS causing the faults. Was your external 5vdc power supply external to the NT's battery and R/R?
-I'd sort out the high temp R/R wiring first.
-Lots of wiring & connectors between the ECM and TPS.....ECM Connector, 10 pin connector near rear throttle body, TPS connector & all wiring.
-The ECM could be failing and the circuit that gives a low (or Hi) TPS volt fault could be failing and causing an erroneous fault code and forcing engine into fail-safe mode.
-Since you are pretty deep into trying to fix this, it may be worthwhile to find out if your TPS faults are Hi or Lo Volt fault. Maybe a Honda dealer would be kind enough to read if for you for something reasonable.
Click to expand...

The external 5v excitation I fed to the MAP and TPS was from an external 12v battery thru a dc to dc power supply. It measured 4.97v and was capable of delivering 3amps but the sensors only drew about 50 milliamps nominal (on a clamp-on). I got the TPS error on power-up. I got it to clear and then rode it about 5 minutes before it reappeared.

As to the error being high or low, has anyone ever seen a high error on the TPS? I’m pretty sure the input has the pull-downs enabled to keep them from floating up with an open circuit but anything is possible.

I replaced the bike battery and the rectifier/regulator with new ones and still having the same issues (TPS errors and overheating alternator wires).

It has 24 amps coming out of the regulator. The battery seems to be eating 10 amps and doesn’t seem to roll-off after riding for 15 minutes. The headlights, fuel pump, ECM and other misc systems must be eating the remaining 14 amps. So far I haven’t found any other hot spots or shorting shunts anywhere.

Next I’m going to find the single point ground and clean it up. :(
 
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