I am trying to install a set of ITBs on my 1998 ITR.
I am getting a CEL (TPS sensor error). When I measure the voltage on pins D11 and D22 in a P28 ECU (OBD2A car with harness), I get around 11.6V.
When I measure at the cords themselves going into the TPS sensor, I get 5V no matter how the TPS sensor is adjusted.

Can anyone help me out? Why does it do that? I can't adjust it to 0.5V closed and 4.5V open, no matter what I do...
Thanks.


Modified by DanishR at 2:58 AM 5/5/2005


Modified by DanishR at 5:09 AM 5/5/2005

 

Are you positive that you're probing D11? If so then my guess is that there's something wrong with your jumper/wiring. As I'm sure you are well aware that should be a ~0.5-5V+ (depending on throttle position) input from the TPS, not ~12V as you indicated. The TPS input/outputs (TPS, VCC2, SG2) from the ECU to the sensor have nothing tied into them from the factory, that's just to say that what you see at the ECU (voltage wise) should be the same at the sensor. I'd check your jumper and/or wiring on the harness. You can also feed a 5V+ source to your TPS, along with a ground, just to ensure that it is working correctly. Sorry I can't help you more but it really seems like a wiring problem to me.

 

Actually it was me.. I measured at <U>pin</U> D11 and D22 not <U>plug</U>.
Thanks for helping. I know what to do now.

 

I can't get it to work. When I do as described here: https://honda-tech.com/zerothread?id=1232957
Measuring between the middle wire and - on the battery, I get 0.01V no matter what position the TPS sensor is in.
Does anyone know why?

 

Do you know that your TPS is in good working order? If not try swapping it. Also check to ensure that there is ~5V+ at the "top", yellow wire.

 

I have tried with 2 TPS sensors and I know one of them works, so it can't be a bad TPS sensor.
There is 5V at the yellow wire.
This is the set of ITBs that I am trying to install: https://honda-tech.com/zerothread?id=1219616

Could something be wrong with the bracket the TPS sensor is attached to? What else could be wrong? I am soooo tired of this, so any help is appreciated.

 

That 5 volts you are measuring is a reference voltage.

 

What could the problem be, when the TPS works, it has power, but always shows 0,01V no matter how I adjust it?

(Following the describtion in the link above)
Thanks.


Modified by DanishR at 5:10 AM 5/5/2005

 

The TPS shows the correct voltage when I put it back on the stock TB. It must be the TPS bracket on the ITBs that doesn't work.

Here is a picture of it.


How do I test if it works?


Modified by DanishR at 5:56 AM 5/5/2005

 

I'm not sure my info will be of any help to you, but I found it a lot easier to just use the stock Suzuki GSX-R TPS sensor on my ITB's. I had to file/drill out the slot to get enough adjustment to get the .500 volt reading at idle, and figure the out which of the 3 wires went where, but other than that it was cake. It bolted up nice and clean, and gave me no problems.

If you choose to stick with the Honda TPS sensor, you will have to make sure that the sensor is adjusted enough to get a reading. If I remember correctly, you have to rotate the Honda one about 15° - 30° to actually get it to "start" reading (so there is a "dead" spot in the beginning (make sense?)), and from there, the voltage will go from .5V - ~5 volt as it is rotated.

Personally, I measured my voltage right at the TPS sensor, not on the ECU. That made it a lot easier to make sure I was connected correctly, and could make the adjustments very quickly. I just poked a small hole with a needle, or the sharp tip of the multimeter, in the insulation of the wire from the variable (.5 - 5V wire) lead (yellow if I remember correctly), and stuck the black probe in the 8-gauge ground wire coming off the valve cover. Then I was able to make whatever adjustments I needed without having to f#ck with 2 probes, under the dash and all of that stuff...

Hope it helps,
Adrian

 

So I should be able to get a reading &gt; 0V from the Honda TPS?
I have tried adjusting it within the available range but it is always the same.
I don't have a Suzuki TPS to try

 

Yes, with the Honda TPS and ECU plugged in, AND the ignition on, you should be able to get a variable signal, from ~.5VDC all the way to 5VDC, when the TPS is rotated.

If I were you, I would mess around with the sensor off of the ITB's, (just in your hands), to see if you can get the readings you need. That would eliminate any issues due to mismounting and such...

Here are some pages out of the FSM that might help...

http://www.redpepperracing.com...a/acf
http://www.redpepperracing.com...a/acg

It looks like:
pin D22 is the Ground leg (Green/Blue on the TPS)
pin D20 is the constant +5VDC leg (Yellow/Blue on the TPS)
and
pin D11 is the variable +.5 to +5VDC leg (Red/Black on the TPS)

So with everything plugged in and the ignition on, you should be seeing a variable voltage from the Red/Black wire on the TPS to the Green/Blue (or chassis ground) wire.

This shouldn't be too big of a deal, unless you don't have everything plugged in when you are checking, or the ignition wasn't on, or you have a broken wire somewhere (which the 2 pages from the FSM will help you find...)

Let us know,
Adrian

 

The TPS sensor problem is solved thanks to you guys
I never realised how a TPS sensor works before now. I took it off to fasten a bolt keeping the bracket in place, and put the TPS sensor back in wrong. I don't think that little pin on the TPS was between the two "things" on the bracket. After I put it in correctly I could adjust to 0.5V closed.
Thanks

But now I have another problem... LOL.
When I start it, it goes to about 2200 rpm, then it seems like the gas is released (wideband shows, injectors shut-off), then it falls to around 1200rpm and starts over. Goes up and down like that.
What could be wrong? It doesn't give a CEL.

 

I had a similar problem with my stock ECU. If I gave it a little gas, it would rev up slightly, and then die, and the catch and drop again. I had to set my TPS voltage lower than .5V at idle, more like .42V, and the problem went away.

Also, at the lower idle voltage, the daily driving on the stock maps was a lot better.

I'm pretty sure that could have been "tuned out", but it got stolen before I got it on the dyno...

Mine also would fall on its face at about 3500 rpm, because I think the map was dumping way too much fuel and it would bog...

Adrian

 

Thanks Adrian. I'll try that next time I work on the car.

 

Yes, that helped. Thanks!

I have another TPS problem though I can adjust it to 0.5V or 0.6V or whatever, but when the Throttle bodies are open, it reads 4.97V or very close to 5V. It seems the range is wrong. I can't adjust it to around 0.5V closed and 4.5V open. Is that because of the bracket the TPS sensor is attached to is contructed incorrectly? As a understand how the TPS sensor works I can't adjust the open and closed voltage seperately. Is that correct? Should I try to modify the bracket?