how to change the tps on a honda

the throttle position sensor [tps] on a honda throttle body is usually
very reliable. but on high mileage vehicles, they can fail, and the
honda recommended repair is replacing the whole throttle body - very
expensive. the reason for this is presumably calibration, which is very
important - it's installed with shear-head screws to prevent that being
messed up. however, if calibration can be preserved, there's no reason
not to change the tps if you can get one.

here is how to do it:

1. go to a junk yard. you'll need to get a tps sensor connector and
some spade terminals so you can make a tool like this:

http://www.flickr.com/photos/38636024@N00/4352880344/

2. you'll also need to harvest a sensor. automatics have less wear on
them than stick shifts, so choose the former if possible. [also, the
88-91 dual point civic/crx injector sensors are different from those on
the 4-point injector sensors, even though they appear the same at first
sight, they are set to rotate in opposite directions.]

you can also buy sensors new from places like this:
http://www.jhpusa.com/store/pc/viewPrd.asp?idproduct=2439&idcategory=375
i believe they are for 4-point injection only since they are commonest.

3. remove the sensor by removing the shear-head screws. i recommend
using [carefully] a sharp chisel on one edge of the screws to start them
rotating. after a few taps, these screws can be rotated and removed by
hand. like this:

http://www.flickr.com/photos/38636024@N00/4450135927/
http://www.flickr.com/photos/38636024@N00/4450135929/

this is on a 90 crx, but the principle is the same for others.

3. before you start work on your own vehicle, this is MOST IMPORTANT!!!
get calibration readings from the old sensor first! you do not need
to remove the throttle body from the vehicle!

3.1 on a cold engine, using the calibration tool you made from #1,
connect in line with the plug and the old sensor still in position.

3.2 turn the ignition on, but do not start the engine.

3.3 for both idle position and wide open throttle [wot] position, note
the voltage reading between the middle wire on the sensor and one of the
other leads. read precisely and repeat for idle and wot three times to
be sure.

3.4 turn off ignition and remove tool from sensor.

4 remove old sensor the way you did at the junkyard. place the new
sensor in position and lightly position new screws so that the sensor
can be rotated for calibration.

new screws are M5x16x0.8. like osh screw part # 9214446.

5. reconnect sensor calibration tool, and turn on ignition [no engine
start].

6. rotate sensor until the readings for idle and wot are identical to 3.3.

7. snug up the screws.

8. check one last time, turn off ignition, disconnect all tools, plug
the sensor back in, close the lid and enjoy.

it is possible to disassemble your old sensor and "repair" it by
spreading the wiper fingers so they contact different parts of the
potentiometer track than those that have worn out, but i wouldn't bother
unless you're stuck in the outback and can't find any other parts.

 

| 6. rotate sensor until the readings for idle and wot are identical to 3.3.
0.5 & 4.4 v from my F20A 's tps : I used a pc's 5v to feed tps to
see these 2 voltages. www.aa1car.com/library/tps_sensors.htm

Do you know whether ECU produces this 5v via a buck convertor
? My fuel*injectors depend on resistors ( wasteful of amps ) to
get their lower voltages, I wish my * have a buck convertor
originally.

 

| 6. rotate sensor until the readings for idle and wot are identical to 3.3.
0.5 & 4.4 v from my F20A 's tps : I used a pc's 5v to feed tps to
see these 2 voltages. www.aa1car.com/library/tps_sensors.htm

Do you know whether ECU produces this 5v via a buck convertor
? My fuel*injectors depend on resistors ( wasteful of amps ) to
get their lower voltages, I wish my * have a buck convertor
originally.