EFI sensor trouble

Tourguy

Guest
So I've got 8 blinks of the MIL, which indicates throttle position sensor problem. Sounds simple enough to replace the sensor and see if that solves the problem right? Well, not so fast there. Seems Honda wants about $900 to sell me a whole throttle body in order to get the sensor. Yes, I've got the official service manual and there are a number of tests which may indicate a less expensive solution, and I will follow those possibilities first. But it seems crazy to me that a ten dollar part cannot be bought in this situation. The word "ransom" comes to mind [and negativity toward Honda].

Anyone else want to chime in on this situation? Has this sort of thing happened to others on the NT? Any alternate solutions if it does turn out to be just the sensor?
 
If I remember correctly I think this error is for the TPI and/or a voltage problem. If this is the same problem I am thinking of then others have actually found the problem to the regulator rectifier.

Do a search of the forum and see what turns up.
 
There is some info on the UK's Deauville site. If your not a member google " tps site:deauvilleuk.org " for some ideas. Some claim to have had success using contact cleaner or WD40 cleaning contacts or the Throttle Position Sensor itself.

If you end up buying throttle bodies, hondabike.com (local in Oly or Tacoma) and Partzilla.com has it for $510- $550. At least you can negotiate the ransom.

I would have thought that some of our British pals would have come up with an alternative part number for the TPS by now. It may not be a Honda part number, just a part number....someone is making them. If you pay to have your throttle bodies replaced ask for the old throttle bodies and pull the old TPS out for closer examination. Sure would be nice to find an alternative to ordering the entire throttle body.
 
I have not had the ty pe of problem you describe. Occassionaly I will get the check engine light. I have found that raising and lowering the side stand with a sharp action will usurally straighten it out and problem solved.. It might also be like some of the other newer vehicles that sometimes need to have the battery disconnected and left unhooked fro a few minuts and then rehooked will sometimes cure problems.

Oh for the good old days of a simple system without all of the extra added systems!

Eldon

Is this a 2011 bike & if so it should still be under factory warranty??
 
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Tourguy, I had the same MIL indications the first year I had my NT. The bike would run OK even with the MIL blinking for a while. And after a while the MIL went off. But then it came back on just as I was entering rush hour traffic on I-25 in south Denver one afternoon and the bike would barely run. After chugging along a ways I managed to get off the interstate and shut the bike off and restarted it. It still didn't run right but it got me to my dealers. I turned the bike off when I got there and the light went out and the bike ran fine.

Naturally!

But they checked the codes and (IIRC) that code indicates a low or high voltage at the throttle position indicator. They changed the rectifier/regulator and I haven't had any more trouble. They also changed the plug caps, but they did that just because I mentioned the recall (which had just come out) not because they thought it was the cause of the MIL indication.
 
Honda integrated the TPS into the throttle body. Unfortunately that means when the TPS goes bad, you are forced to replace the entire assembly. I don't believe Honda is holding anyone "hostage". I suspect they felt that the reliability of the TPS was such that they could integrate it into the throttle body.

My wife's NT was show signs of power loss while riding. The MIL would flash a code of 8 indicating low or high voltage at the TPS. The service manual points to 3 possible issues.

  • Poor connector pin contact. Make sure that all of the pins in the connectors are properly adjusted and make good contact.
  • A malfunctioning ECM
  • A bad TPS

After "humoring" the local Honda dealership with their suggestion that the connectors were likely the culprit, my wife's NT shortly settled back into loosing power and throwing a MIL of 8. I captured the behavior on video to show them exactly what was happening (they were never able to reproduce the issue as sometimes it would take hundreds of miles to act up). They said that they tested the TPS and the voltages were correct throughout the sensor's movement. I don't think they thought about holding the sensor at various positions for long periods of time though.

[video=youtube;N_sqen6hSbQ]https://www.youtube.com/watch?v=N_sqen6hSbQ[/video]

Since they had already verified that the connectors were okay (and through some insistence from me) they obtained authorization to replace the throttle body (just to replace the faulty TPS). That was almost 4k miles ago and not a single instance of power loss or MIL illuminations. Problem solved!

I believe the bad TPS on my wife's bike would only act up if you maintained a specific throttle position for a few minutes. It was at that point that the fault would occur and the bike would go into "limp home" mode. Shutting the bike off and then back on would let it operate normally until you maintained that throttle position (seemed to be about 60-70mph on a flat surface, less if going up hill) and the MIL would illuminate and power loss would return.

Good luck with yours. I'm just glad I had the extended warranty. The $700 throttle body in parts alone was more than the extended warranty.

Tourguy said:
So I've got 8 blinks of the MIL, which indicates throttle position sensor problem. Sounds simple enough to replace the sensor and see if that solves the problem right? Well, not so fast there. Seems Honda wants about $900 to sell me a whole throttle body in order to get the sensor. Yes, I've got the official service manual and there are a number of tests which may indicate a less expensive solution, and I will follow those possibilities first. But it seems crazy to me that a ten dollar part cannot be bought in this situation. The word "ransom" comes to mind [and negativity toward Honda].

Anyone else want to chime in on this situation? Has this sort of thing happened to others on the NT? Any alternate solutions if it does turn out to be just the sensor?
Click to expand...
 
Just as a matter of routine, I always use dielectric grease on sensor connectors that have been unplugged during a service.
 
I put a teeny dab at the opening of the female socket for each pin. it's just too chancy to try and put grease on the male side and besides, you won't want to chance bending some of those tiny pins.
 
I also had the eight flashes on the MIL, started a thread on this, initially thought it was the battery which I changed, still had the occasional MIL, experienced a partial engine shutdown (possibly a limp home mode), and changed the spark plug caps. Since then, I still get an occasional MIL, always 8 flashes when I put the kickstand down to check. If I shut down the bike and restart, the MIL goes off correctly within a few seconds of first turning the key. I now basically ignore the MIL. I have purchased a new regulator/rectifier and keep thinking about installing it to see if if completely resolves the problem. But at this point, my assumption is that my MIL is reacting to a voltage level, but otherwise there does not appear to be an issue that needs to be fixed. I'm taking off on a camping trip tomorrow, and always wonder if I am overlooking something. But so far, since changing the spark plug caps, I have had no running problems.
 
The symptoms on my wife's NT were similar to what you described. Initially just the MIL would come on with no apparent driveability issues. After sometime, the bike would loose power as shown on the video I took.
video I took.
Eventually, this became more and more frequent. We could pretty much guarentee it's occurrence on any ride of 50 or more miles. The 2 mile test ride the dealer would take to recreate it....not so much. :frown: So the video came in handy.

Nearly 4k miles since the throttle body has been replaced and not a single MIL. I suspect your issue is in fact the TPS. Our problem only seemed to occur when the throttle was in a specific position for an extended amount of time. It was just a "dead" spot on the sensor. To bad it is integrated into the throttle body. Honda turned a $30 fix into a $700 repair. :mad:


NoVa Chris said:
I also had the eight flashes on the MIL, started a thread on this, initially thought it was the battery which I changed, still had the occasional MIL, experienced a partial engine shutdown (possibly a limp home mode), and changed the spark plug caps. Since then, I still get an occasional MIL, always 8 flashes when I put the kickstand down to check. If I shut down the bike and restart, the MIL goes off correctly within a few seconds of first turning the key. I now basically ignore the MIL. I have purchased a new regulator/rectifier and keep thinking about installing it to see if if completely resolves the problem. But at this point, my assumption is that my MIL is reacting to a voltage level, but otherwise there does not appear to be an issue that needs to be fixed. I'm taking off on a camping trip tomorrow, and always wonder if I am overlooking something. But so far, since changing the spark plug caps, I have had no running problems.
Click to expand...
 
Tourguy said:
Seems Honda wants about $900 to sell me a whole throttle body in order to get the sensor.
Click to expand...

There is always the used parts approach on ebay. Here is one for $150.

I know used parts offends some of the "not on my new Honda" crowd, but 10 years from now all NT700 owners will be doing it to their 15 year old NT's. Especially to save this kind of money.

As many MIL codes 8's seem to be happening it is only a matter of time before some curious individual will disassemble the throttle body to get to the Throttle Position Sensor and possibly come up with a less expensive solution to replacing the entire throttle body. I hope it happens before I get a MIL code 8.
 
Had the local dealer do analysis of the problem with their special tester. They gave me a nice printout [full diagnostic] saying an 8-1 code was logged = voltage low. Their bottom line resolution was to replace the throttle body. After they cleared the code, voltage was fine. I've been too busy to ride much but have seen the MIL come on at least twice, once with engine cutting out intermittently while under power. Last time it happened I just turned off the key hoping for a system reset and had no problem at restart.

Thank you to all who have shared their experiences and thoughts on this. I intend to provide updates as I work my way thru various possible solutions for benefit of others who face this issue. Too busy working this summer, but have some $$ to throw at it now. :)
 
Voltage low is the key to your problem. This sounds like the same problem others have had AND it was fixed by replacing the regulator rectifier.

Seagrass
 
That was my symptom and that was the solution. At least I haven't had an MIL indication since the regulator/rectifier was replaced.
 
I had similar issues starting in the fall of 2010 that were not resolved until the late fall of 2013 (after riding season was over) by replacing the throttle body. Fortunately for me, Honda covered the repairs under what they called an "emissions warranty", which is good for 30,000km (18 thousand and something miles). I'm disgusted by the length of time it took to resolve the problem and repeated trips to the multiple dealers but it did not cost me any money.

You might want to ask about the emissions warranty if you are still under 18,000 miles.

Kevin
 
Yes. I think you'll find that the TPS is bad. There are a number of sensors on the bike and most of them will throw a code for low/high voltage. Since you aren't receiving codes from those other sensors (which I would expect if the reg/rec was acting up), and if you have checked the connectors and they are making good contact, the TPS (and the replacement of the throttle body) is you likely fix. Unfortunately, that throttle body is quite pricey. :(

Replacing the throttle body is not difficult. No special tools are required. You could save yourself $200 and do it yourself.


Tourguy said:
Had the local dealer do analysis of the problem with their special tester. They gave me a nice printout [full diagnostic] saying an 8-1 code was logged = voltage low. Their bottom line resolution was to replace the throttle body. After they cleared the code, voltage was fine. I've been too busy to ride much but have seen the MIL come on at least twice, once with engine cutting out intermittently while under power. Last time it happened I just turned off the key hoping for a system reset and had no problem at restart.

Thank you to all who have shared their experiences and thoughts on this. I intend to provide updates as I work my way thru various possible solutions for benefit of others who face this issue. Too busy working this summer, but have some $$ to throw at it now. :)
Click to expand...
 
OK, here is another tentative vote for the voltage regulator. I have had 8 flash MILs over the past year, about once every 10 or 15 starts. MIL goes off if I shut down and restart, and with one recent hiccup aside, I have not had a running problem since I swapped the spark plug caps last year. But still, based on Phil's experience with a new voltage regular, I purchased and installed a new regulator a few weeks ago. Absolutely no MIL's since. So it seems that some folks have 8 flash MIL's that really do affect running, and end up swapping the throttle body. But perhaps for some folks the issue can be resolved with a new regulator.

This story has been going on so long for me that I am still not convinced, but I have my fingers crossed.
 
Rmcapozzi said:
Yes. I think you'll find that the TPS is bad. There are a number of sensors on the bike and most of them will throw a code for low/high voltage. Since you aren't receiving codes from those other sensors (which I would expect if the reg/rec was acting up), and if you have checked the connectors and they are making good contact, the TPS (and the replacement of the throttle body) is you likely fix. Unfortunately, that throttle body is quite pricey.

Replacing the throttle body is not difficult. No special tools are required. You could save yourself $200 and do it yourself.
Click to expand...

Agreed on thinking the TPS is the likely offender.
Pay attention to the codes/MIL prior to starting the engine. If you have an active MIL due to a TPS (or any other sensor) with the engine off, the alternator & regulator/rectifier can no longer be suspect for causing voltage problems at a sensor. The only component providing voltage to all sensors is created by the battery alone with the engine off. If you get the MIL while riding, read the code before turning the engine off. Once the code is read with the engine running, kill the engine and check if the same MIL code can be read with the ignition switch on prior to re-starting the engine.

I would check all possible connectors closely before spending the $500+ for a the throttle body because 1) connectors frequently get dirty & create a high resistance connection and 2) it is free to check them. The possible connectors would include the connector at the TPS, both connectors on the ECM, and (the often not discussed in the service manual) the 10 pin connector that is electrically between the ECM & TPS. The 10 pin connector is easy to find by following the wires from the TPS back toward the ECM. If after checking all connectors the TPS codes continues......then replace the $30 TPS by buying a $500 throttle body. It's maddening.
 
dnktng said:
Agreed on thinking the TPS is the likely offender.
Pay attention to the codes/MIL prior to starting the engine. If you have an active MIL due to a TPS (or any other sensor) with the engine off, the alternator & regulator/rectifier can no longer be suspect for causing voltage problems at a sensor. The only component providing voltage to all sensors is created by the battery alone with the engine off. If you get the MIL while riding, read the code before turning the engine off. Once the code is read with the engine running, kill the engine and check if the same MIL code can be read with the ignition switch on prior to re-starting the engine.

I would check all possible connectors closely before spending the $500+ for a the throttle body because 1) connectors frequently get dirty & create a high resistance connection and 2) it is free to check them. The possible connectors would include the connector at the TPS, both connectors on the ECM, and (the often not discussed in the service manual) the 10 pin connector that is electrically between the ECM & TPS. The 10 pin connector is easy to find by following the wires from the TPS back toward the ECM. If after checking all connectors the TPS codes continues......then replace the $30 TPS by buying a $500 throttle body. It's maddening.
Click to expand...

I am following your logic BUT I do not think it is correct. If the code is "low voltage" it could also be from a failing battery. Many of these bikes have had a battery replacement already and these AGM batteries are notorious for spectacular failures with or without any warning. If a diode is failing in the regulator/rectifier it could also be affecting the supplied battery voltage as some battery voltage could be leaking to earth. The regulator/rectifier is an integrated part of the electrical system and if it is not working correctly then there could be many and varied symptoms.

When I am trouble shooting a problem I start with the easy, quick and cheapest options (as you have suggested) and then work my way up to the dearest option. As the regulator/rectifier is known to be a cause of this problem and it is cheaper to replace than the TPS then my suggestion is to try the regulator/rectifier first. If this does not fix the problem the regulator rectifier can always be on sold to someone who needs it on this forum or elsewhere.
 
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Tourguy said:
Had the local dealer do analysis of the problem with their special tester. They gave me a nice printout [full diagnostic] saying an 8-1 code was logged = voltage low. Their bottom line resolution was to replace the throttle body. After they cleared the code, voltage was fine. I've been too busy to ride much but have seen the MIL come on at least twice, once with engine cutting out intermittently while under power. Last time it happened I just turned off the key hoping for a system reset and had no problem at restart.

Thank you to all who have shared their experiences and thoughts on this. I intend to provide updates as I work my way thru various possible solutions for benefit of others who face this issue.
Click to expand...

Don, here are a couple of idea you may consider.

There is a used throttle body on ebay in Oregon. Here is a link. $150 is cheaper than new, but a used throttle body is a little risky.

There are also used rectifier regulators on ebay for <$100 if you decide that may be a cause of your problems. A used regulator rectifier is a lot less risky than a used throttle body.

I have a good used rectifier regulator in my NT. Ride down to Yelm and we could swap regulator/rectifiers in about an hour. Whoever gets the next code 8 it would be 100% positive if your rectifier regulator is the cause. Disclaimer: I am only willing to swap rectifier/regulators if your only electrical issue is the code 8 popping up. If you are having other electrical faults that are the classic "bad regulator/rectifier" symptoms like:
1) replaced the battery 3 times in a year,
2) lights dim, then bright, then dim,
3) burning up a lot of light bulbs
4) acrid smoke rolling out from under your seat or
5) "why won't my grip heaters stay on?".....,
I'm not interested in installing a strongly suspected regulator/rectifier in my NT in that case.

PM me if interested in swapping. I pulled my regulator yesterday, it can be done by just removing the seat and side cover. Don't get greedy though, I'm not volunteering to swap throttle bodies.:smile:
 
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