TPS Sensor

[ercbf]

Gotta a question. The tps sensor that is on the 2000 carbed nomad. Is it a true tps? In other words, is it using the reading for timing advance? Also, will a inoperable tps on a carb cause reduced fuel economy? Thanks for any answers guys.

[ringadingh]

I didn't think a carbed bike would have a tps, the timing advance would be controlled by the ignition module in most cases that Ive come across.
Ive never seen a carbed Nomad so maybe they are a little different than what Id assume them to be designed.

[ercbf]

Thanks Ring. It is definitely a tps. I researched it on the CVK carb. The reason I was asking is because I noticed something today while working on my Nomad.

I was installing Chuckster's plates today, so I had the tank off. Anyway, noticed that this sensor at the carb was unplugged. The last time I was in there doing any work is about a month ago, when I re-jetted and re-tuned my carb for the aftermarket exhaust.

I have been wrestling with the fact, while having no performance loss with the bike, my mileage was suffering a little, as much as 5 to 8 miles per gallon. That's approximately 20 to 32 miles a tank! I knew I tuned the carb correctly....Even with out being dyno'd, but trust me, she's not too rich, not too lean. I chalked the loss of mileage due to weather, driving habits...human error, heavy traffic,etc. I left the tps unplugged accidentally when I did the carb work.

After reading a bit today, I find out that a tps on a carbed bike can cause fuel mileage to suffer. I plugged it back in today, installed the the plates and went for a little(10 mile) ride. Definitely noticed a difference in throttle response....nothing over the top mind you, but a difference, none the less.

Next time I gas her up, I am going to monitor the mileage closely, the end result answer is driving me crazy, I need to find out if this simple tps was causing me my woes, lol.

Btw, on a side note, after installing Chuckster's plates, I definitely noticed a difference in the sound of my exhaust. It is not as aggressive as it was before. I like it.. loud, but not annoying.

[macmac]

I couldn't answer for the same reason Ring can't. I will look into this when I get a chance.

[AlabamaNomadRider]

Sounds like you solved your problem Eric. I sure hope that was the culprit causing you lower miles per gallon.

[ercbf]

Originally Posted by macmac

I couldn't answer for the same reason Ring can't. I will look into this when I get a chance.

Thanks Mac, but don't worry about it at the moment. I will know the answer within the next tank of gas.

Alabama, thank you, hopefully it is the prob. I am pretty confident.

[blowndodge]

I don't mean to sound stupid but what is the function of a TPS on a carburated bike? I've adjusted my TPS numerous times on my FI 2006 Nomad and realized that it wasn't going to do what I wanted it to do, namely richen up the mixture at part throttle settings.

TPS on FI bikes signal the ECU to fire the injection longer or shorter depending on the Throttle postion as well as timing adjustments. A TPS on a carburated bike would need to send "this" info to a processor for a function to be performed. I didn't know Carbed bikes had ECU's? And if they do,,, why? You've stated you re-jetted your carb which is 90% of the function of a ECU on the FI bikes (altering fuel mixtures). There is no electronic firing pulse gadget hooked up to a carburator is there???

[macmac]

BD, That's why I wanna know too.. later when the garden and the trees are down, maybe a rainy day comes, or something else happens and keeps my in I can crack a book.

This is lunch time and I been in the woods feedin the black flies and sketters, and then in the garden wonderin what the heck these wanna be squash are, and if i should trans-plant em.

I got about a week to how rows and be on time. Frost 2 nights back see?

Just might be a part of his rev counter/ limiter for all I know... That is a total guess.

[ringadingh]

I was thinking the same thing Brad, it doesn't make sense to me, but some of those Japanese ideas are pretty creative.

[ercbf]

Copied this from an online service manual on a cv carb from a honda.

The carb pictured here
is from a Honda
Ruckus. Your carb may
be more like this one.
The Ruckus is very
similar to the CH150 carb. but it has a throttle position sensor or “TPS”. The
TPS tells the engine control module what is going on so it can adjust the
ignition to let the engine run even better. The sensor itself is mounted at
the end of the throttle shaft opposite of the throttle wheel (where the
throttle cable attaches to the carb)

[macmac]

yeah I can see this 'like' vac advance which is a minsnomer, since really most are vac retard set ups... mainly because there is no vac at WOT.

[ercbf]

Well, after taking an extended trip this weekend, I am now positive that the unplugged tps sensor affected my mileage. I am now back to approx 42 gals. per mile.

[macmac]

Better power too I bet..

[ercbf]

Originally Posted by macmac

Better power too I bet..

Yes, a noticeable increase Mac. The bike felt "right" finally after all this time. I am very pleased.