TPS Gauge for better economy?

[whiskey_juliet]

I own a '95 Honda Civic VX, 193,XXX mi. Right now stock I am averaging 40+ city. Ive been doing a good amount of research on how to bump the mpg's up and after some recent driving I have decided to build a TPS gauge to give real time readouts on throttle positioning.

Why do I want to do this?
I find myself checking my throttle position often. What I mean is letting off the throttle and then back on to find out where I stand. I don't like doing this. I have read a post or two of other people suggesting this but I never found anything completed. And gauges that are offered that can read this off the TPS are too costly in my opinion.

What do I think I will gain?
IDK? But I feel like it would challenge me to always be at my lowest possible open throttle.

How am I going to do it?
My friend and I who share a passion for R&D have come up with this as a rough starting point. 25 LED's arranged in a straight line. A measuring device on the TB (Ive heard that you can get a readout from the TPS by splicing into one of the wires. With some circuitry it can be routed to the LEDS and be read in a progressive manner based on voltage). Luckily we also have a Nerdy friend who loves messing with that type of circuitry.

Anyway, the idea is to be able to read the throttle position accurately under 25%, moderately from 25% - 50%, and then Roughly from 50% - 100%. The reason for the different readout zones is because I feel that a digital gauge would be too expensive yet the most accurate. An LED strip could be just as accurate if you wanted to use 100 LED's but we dont want that because we are trying to keep costs down, not to mention a strip of LED's that big could be an eye sore on the dash.

We havent yet decided on those readout zones nor the actual number of LED's to be used. Mostly we havent decided on anything yet since we are still brewing the idea and whether or not it will be effective and cost effective.

So that is why I am here. I am looking for input from you, the ecomodder.
Please be gentle, this is my first eco car and I really want to help add to our success.

[nemo]

Interesting idea and would be of great assistance maintaining throttle position going up hill. You may be better off building a instantaneous MPG meter, see MPGuino. Then trying to keep the reading above the MPG you are trying to obtain. This type of device can help you find speeds at which your car gets higher mpg than a couple of miles per hour on either side of it.

But do let us know what you do and the results you achieve.

[whiskey_juliet]

So I checked out that MPGuino Kit. I like it and I really like the price of it. And that is what I am trying to do with the TPG (Throttle Position Gauge) as I will call it. In the event that it does in some way help with keeping track of low throttle positioning as well as any better MPG's I wouldn't mind offering the idea if not a kit to the general public. I will definitely be purchasing one of the MPGuino's in the near future. Such a great price for what it does. And it looks good too.

[IsaacMTSU]

I messed with the TPS on my SR20DET engine...not good, even reading the value of it through the multimeter cause enough interference that the engine was erratic. Making a separate sensor (maybe a potentiometer) on the throttle body would be the most accurate way and you could tweak the circuitry easier.

[whiskey_juliet]

Originally Posted by IsaacMTSU

I messed with the TPS on my SR20DET engine...not good, even reading the value of it through the multimeter cause enough interference that the engine was erratic. Making a separate sensor (maybe a potentiometer) on the throttle body would be the most accurate way and you could tweak the circuitry easier.

That is what I was worried about happening. My Tech guy first suggested a potentiometer. But since the goal was to keep this as cheap as possible we were looking into all possibilities.

Thanks for the info. Just the kind of stuff I am looking for.

[AndrzejM]

Hi,

I think you can do that with analog voltimeter and a very simple set-up

Diagram above is just to give you an idea.

[JasonG]

What type of meeter were you using ? Analog meters will pull the circuit down too much.
The TPS is a 0-5V signal. I use only digital meters and have not seen an issue.
The draw from the LEDs should be small enough not to pull.the circuit out of range.
Cheap digital meters can be found for under $30.
Hack out the display and mount it to the dash. A 12V to mater battery voltage converter willl keep you from having to turn it off and change batteries often.
A voltage regulator such as a 75XX from Radio Shack will run <$5

Have fun :-)

[whiskey_juliet]

More and more good responses. Thanks fellas. Although Im not the wiring guy but Ill definitely be passing this info along to him.

[msc]

What would be the advantage over simply installing a manifold vacuum gauge? I would expect a vacuum gauge to be more useful and easier to install. It's my understanding that on Honda's of the era the TPS is used by the ECU more for advance warning of where the manifold pressure is going then for direct control. Take away the TPS and the engine still runs OK but the throttle response is not as good.

Mike

[mja1]

most sensors and electronic devices on the engine run off of a range of specified voltages, some simpler sensors don't care as much if the wires are extended and resistance is increased within reason (the intake air temp sensor - a thermometer comes to mind). The TPS I wouldn't be splicing and adding wires to test where it is. Remember every sensor on the engine is registered in tables in the ECU, this means that somewhere out there is a product that will allow you to read those sensors off the OBDII port without changing any sensor wiring. Some are very expensive (tuning software), some like the scan gauge may read your TPS around 100-150$. There may even be cheaper alternatives.

x2 on the vacuum gauge.