Last updated: February 8, 2003

TPS Adjustment

Date: Thu, 16 Oct 1997 10:23:00 -0500
From: "Westbrook, Chuck"

Special Tools Needed:

a high impedance volt meter (preferably with digital read out) and one alligator tip if possible
7mm 1/4" drive socket, 1/4" L bar(short breaker bar), 3/8" to 1/4" adapter, 3/8" rachet (or some similar 7mm tools)
safety pin opened up to form a 90 degree angle

TPS Connector Points (4 lined up vertically) and required voltages:

2nd from the top (green wire with red strip), this goes to the 3F ECU connector. Closed throttle +V range is 0.75 to 1.25. Fully open throttle +V range is 4.8 to 5.0.
Bottom (black wire with green strip), this goes to the 3G ECU connector. Closed throttle +V range is 0.1 to 0.7. Fully open throttle +v range is 4.2 to 4.6.

Procedure:

Start and run engine until at normal operating temperature and the fast idle cam is at idle position.
Turn off engine.
Remove the AWS hose that connects to the long curved inlet pipe and to the AWS solenoid behind the throttle body.
Remove the hose from the pressure sensor on the firewall and tuck it down out of the way. Procedures 3 & 4 are to make room to reach the 2 TPS bolts.
Using the 7mm socket, 3/8" to 1/4" adapter, and 3/8" rachet, 1oosen the lower TPS bolt.
Using the 7mm socket and 1/4" L handle, barely loosen the top TPS bolt.
Connect the negative volt meter lead to a good ground point. I used one of the ground points in the diagnostic connector.
Insert the safety pin point into the 3F or 3G TPS connector between the wire and rubber weather seal. Using the alligator tip, connect the volt meter positive lead to the latch end of the safety pin.
Turn on the ignition without starting the engine. If there isn't a voltage reading, then readjust your ground and TPS connections until you do.
Note the voltages at closed and fully opened throttle.
Do the same for the other TPS connector point.
If all four voltages are not within the specified ranges, loosen the top TPS bolt and rotate the TPS until all four voltages are correct.
Tighten the 2 TPS bolts and reassemble everything. Do not over tighten the two TPS bolts. Their listed torque is 14 to 21 inch pounds!
Drive the car then readjust the idle air bleed if necessary.

Date: Thu, 16 Oct 97 11:50:31 -0500
From: "Linthicum, Sandy" (linthias@sandy-ntws.usps.gov)

Note: When I recently had the TPS on my 93 R1 replaced, the "bolts" for the TPS were actually phillips head screws and were extremely hard to get loose. The new TPS now has allen head bolts instead of screws.

Date: Mon, 15 Dec 1997 06:55:03 -0600
From: Louis Herndon (herndonl@gar.esys.com)

Here a quick, inexpensive solution to making a throttle position sensor (TPS) adjustment tool that doesn't require soldering wires to bulbs.

Go to your local automotive outlet and buy two license sidemarker sockets, bulbs to fit the sockets (I used "194" bulbs), and a package of 1/4" insulated spade lugs if you don't already have those laying around. The sockets need to be the type that have both a hot lead and a ground wire. The style I bought (Conduct Tite part number 85814) had a brown and black wire coming out of the plastic socket.

To fabricate the tool, twist the two brown leads together and crimp into one of the spade lugs. Crimp a lug on both of the black wires and install the bulbs. Plug the lug for the brown wires into the slot on the green adjustment connector (next to the passenger side shock mount) that's on a level by itself. Plug the black wire lugs into the two side by side slots and go get your screwdriver.

Warm the engine to operating temperature and, if both lights are not on, turn the TPS adjustment screw clockwise to the point where both bulbs light and then turn the screw counterclockwise to the point where one of the lights goes out and then turn the screw another 1/8 turn. Try to put as little downward pressure on the screw as possible while making the adjustments. Wahlah! (sic) Perfect adjustment of the TPS.

___________________

The following was posted for a TII (2nd gen), and from what little I know on this (haven't tried it yet), it seems similar to the above for 3rd gens. --Steve

Date: Wed, 07 Jan 1998 22:21:00 -0700
From: Chuck Sterling (csterlin@nmsu.edu)

I went to Radio Shack, bought a package of little 12v lamps with leads attached and a package of 1/4" flat male crimp-on plugs. Twist together a lead from each lamp and crimp them together into one plug. Each of the other two leads gets its own plug. Crude schematic:

+-------->
|
(Lamp)
|
+-------->
|
(Lamp)
|
+-------->

The test socket has three 1/4" female receptacles. The one that is at a right angle to the other two (which are side-by-side) is the one that gets the plug with two wires. Each of the other receptacles gets a plug with only one wire.

The results were satisfactory. It looks like the cold start problem is fixed, though one day's observation is hardly enough on which to base a thesis.

I think that the less current the lamps draw, the better. Heisenberg was right... I didn't try to compare wattage ratings; I just chose the smallest, cheapest ones that had insulated leads attached.

Date: Tue, 28 Apr 1998 12:39:05 -0600
From: "Sterling, Chuck" (csterlin@smtp3.wstf.nasa.gov)

Get a couple of *small* 12v lamps with insulated leads, and a pack of crimp-on 1/4" male spade connectors from Radio Shack or such. Put one 1/4" connector on *one* of the leads on each lamp. Take the other two leads, one from each lamp, twist them together and put one 1/4" connector on them.

Now it looks something like this (use your imagination):

+-----+
| 1/4 +----------------+
+-----+              (LAMP)
               +-------+
+-----+        |
| 1/4 +--------+  <--- 2 wires to this connector
+-----+        |
               +-------+ 
+-----+              (LAMP)
| 1/4 +----------------+
+-----+

Viola.

The connector on the engine has three sockets, one for each spade connector, arranged sorta like this:

+---------+
|    ---- |
| |       |
| |       |
| |       |
|    ---- |
+---------+

The two sockets to the right of this sketch, the ones shown horizontal and parallel to each other, each get a 1/4" connector with one wire.

The one socket to the left of this sketch, shown vertical, gets the 1/4" connector with two wires.

Get the engine hot, stop it, turn the key back on. With the test wires connected and the throttle closed, only one lamp should be lit. ...make it so. :-]>

__________________

Date: Tue, 28 Apr 1998 15:06:30 -0400
From: lmizerka@nvl.army.mil (Larry Mizerka)

Visit your local Radio Shack and buy 2 of Cat. No. 276-084A ( Red LED Assembly with Holder and Built-in Resistor). I think green is also available, if that's you preference. Buy 1 of Cat. No. 64-4040 (Quick Disconnects). Using 3 of the 1/4" male spade connectors, connect the LED black wires each to one spade connector and the LED red wires common to another spade connector. That's your TSP tester for about $5. The 2 black connectors plug into the parallel terminals on the green test connector and the red plugs into the other terminal which is positive. If the polarity is not observed, then the LEDs will not illuminate.

Date: Mon, 8 Mar 1999 13:08:36 +0000
From: gpc@amlibs.co.uk

Throttle Sensor

The throttle sensor detects two kinds of throttle opening angles: narrow range and full range. The learning control performed in the ECU makes adjustment unnecessary except when replacing the sensor.
The narrow-range indication is used to judge when the throttle is fully closed and detects the engine idle range, the full-range indication detects the degree of acceleration and is used to control operation of the turbochargers.

Characteristics

The throttle sensor has linear characteristics in both the narrow and full-ranges.
The narrow range portion indicates full throttle opening when the throttle opening exceeds 40 degrees.

Throttle-idle-position auto-adjusting system

Throttle-idle-position automatic adjusting system is incorporated within the ECU.
This system automatically compensates for certain variations in the output signal of the throttle sensors. At idle, this narrow range is set to output a signal of 20% of full-open. With the throttle idle position automatic adjusting system, the ECU will compensate for actual output values of 15-25%.
If the output is less than 15% or more than 25% at idle, the ECU fixes the value at 15% and 25% respectively for fail-safe operation. Operation for the full range is the same. The sensor is set to register a 15% signal at idle, and the ECU compensates within the range from 5-25%. If over or under the signal is fixed at 5% and 25% respectively for fail-safe operation.

Hope that all made sense to you!

_________________

Date: Tue, 7 May 2002 18:32:24 -0700
From: "D Vanditmars" (dvanditmar@deltastar.ca)
Subject: (rx7) [3] Symptom = lurching at low throttle, TPS Adjustment?

The 1993 Workshop Manual says the following:

                    Fully Closed        Closed to Open        Fully Open
Narrow Range        0.75 - 1.25 V       1.0 - 5.0 V           4.8 - 5.0 V
Full Range          0.1 - 0.7 V         0.4 - 4.3 V           4.2 - 4.6V

So after warm-up I have the TPS adjusted for:

Narrow Range      1.0 V
Full Range        0.4 V

I here from other sources that you are to balance the Narrow and Full Ranges so they are about the same when closed, (fully warmed-up idle). But that does not make sense from the voltages I have seen while adjusting.

So is there an optimum initial setting? Or do I just tweek the TPS one way or the other and see how it drives, tweek again, go for a test drive.....?

_____________

Date: Mon, 24 Feb 2003 20:12:56 +0100
From: "Bernd Kluesener" (bklues@swipnet.se)
Subject: RE: (rx7)(3) TPS pin out

Viewed from left to right from the harness side, connector lock spring facing upwards:

    1: 0V (GND)
    2: signal (narrow range)
    3: +5V
    4: signal (full range)