We have just bought a 1994 TR Magna wagon with the 2.6L 4 cylinder EFI engine.

Since purchase it has had a very low rough idle which we improved by adjusting the throttle stop screw to increase idle speed. I now realise this was not the right thing to do and this should not have been adjusted. We also found the real cause of the problem which was a disconnected sensor.

My question is how should I reset this throttle stop screw to the correct position. Is there a procedure for doing this. We have the Haynes manual but it makes no mention of it, perhaps someone has a factory manual that has a procedure?

The car still idles a little rough, particularly when cold. It also uses a lot of fuel and hesitates a bit when taking off from idle.

Any suggestions appreciated.

John in Sydney.

Should also mention that the CHECK ENGINE light comes on for a few seconds after the engine starts.

Thanks.

We have just bought a 1994 TR Magna wagon with the 2.6L 4 cylinder EFI engine.

Since purchase it has had a very low rough idle which we improved by adjusting the throttle stop screw to increase idle speed. I now realise this was not the right thing to do and this should not have been adjusted. We also found the real cause of the problem which was a disconnected sensor.

My question is how should I reset this throttle stop screw to the correct position. Is there a procedure for doing this. We have the Haynes manual but it makes no mention of it, perhaps someone has a factory manual that has a procedure?

The car still idles a little rough, particularly when cold. It also uses a lot of fuel and hesitates a bit when taking off from idle.

Any suggestions appreciated.

John in Sydney.

we had to alter the idle for my old TP 2.6 through the carbi, but obviously you have the fuel injected model which doesnt have a carbie so i dont really know. But its a common problem for 1st and 2nd gen magnas to have idle problems, specially as it heats up they will get worse, can be a bugger to even start on a hot day

well now you've connected the thingi again is it idling way to high? becuase you fixed that and turned the idle up? just start it keep it in park then adjust the idle till its aroud 1000-1100rpms.

We have just bought a 1994 TR Magna wagon with the 2.6L 4 cylinder EFI engine.

Since purchase it has had a very low rough idle which we improved by adjusting the throttle stop screw to increase idle speed. I now realise this was not the right thing to do and this should not have been adjusted. We also found the real cause of the problem which was a disconnected sensor.

My question is how should I reset this throttle stop screw to the correct position. Is there a procedure for doing this. We have the Haynes manual but it makes no mention of it, perhaps someone has a factory manual that has a procedure?

The car still idles a little rough, particularly when cold. It also uses a lot of fuel and hesitates a bit when taking off from idle.

Any suggestions appreciated.

John in Sydney.


what to say bout this... welcome to the 2nd gen club :D

well now you've connected the thingi again is it idling way to high? becuase you fixed that and turned the idle up? just start it keep it in park then adjust the idle till its aroud 1000-1100rpms.

should idle at 800rpm when its warmed up, 1200rpm when its cold

to set the base idle correctly the spark timing needs to be checked and correct and the idle speed control motor needs to be parked, The workshop manual should tell you which ecu check terminals to bridge to do this.

just find a member called "jellico" on here and PM wanting some info on 2nd gens.

he'll give you everything you need.

Do the 2nd gens have a Positive Crank Ventilation (PCV) valve? I assume they do. Your car has something like 12years of sh!t choking this up. I cleaned mine on my TF and the idle nonsense has stopped!! The Mrs thinks I'm a genius :D

This should work for your 2.6l Astron II as well.

ADJUSTMENT OF IDLE POSITION SWITCH AND
THROTTLE POSITION SENSOR (TPS)
(1) Disconnect the throttle position sensor connector.

(2) Using jumper wires, connect an ohmmeter across terminal
3 (idle position switch) and terminal 4 (sensor ground) of
the throttle position sensor.

(3) Insert a 0.65-mm-thick feeler gauge between the fixed SAS
and throttle lever.

(4) Loosen the throttle position sensor mounting bolts and turn
the TPS body fully counterclockwise.

(5) In this condition, check that there is continuity across
terminals 3 and 4.

(6) Slowly turn the throttle position sensor clockwise until you
find a point at which there is no continuity across terminals
3 and 4. Then, tighten the throttle position sensor
mounting bolt securely.

(7) Connect the throttle position sensor connector.

(8) When using the multi-use tester, connect it to the diagnosis connector.

(9) When not using the multi-use tester, proceed as follows:
*Disconnect the throttle position sensor connectors and
connect the special tool, Test Harness Set, between
the disconnected connectors.
*Connect a digital voltmeter between the throttle position
sensor terminal 2 (sensor output) and teminal 4 (sensor ground).

(lO)Turn the ignition switch ON (but do not start the engine).

(11) Check the throttle position sensor output voltage.
When using the multi-use tester, select item No. 14 and
read the throttle position sensor output voltage.
Standard value: 400 - 1,000 mV

(12)lf the voltage is out of specification, check the throttle
position sensor and associated harnesses.

(13)Remove the feeler gauge.

(14)Turn the ignition switch OFF.


ADJUSTMENT OF FIXED SAS

(A) The fixed SAS has been factory-adjusted. Never attempt to
move it.

(B) Should it be out of proper adjustment, adjust by following
the procedure given below.

(1) Sufficiently slacken the accelerator cable.

(2) Loosen the lock nut on the fixed SAS.

(3) Sufficiently loosen the fixed SAS by turning it counterclockwise
to fully close the throttle valve.

(4) Tighten the fixed SAS slowly to find a point at which it
contacts the throttle lever (where the throttle valve starts
opening). From that point, tighten the fixed SAS further 1 l/4
turns.

(5) Holding the fixed SAS to prevent it from turning, tighten the
lock nut securely.

(6) Adjust the accelerator cable tension.

(7) Adjust the basic idle speed.

(8) Adjust the idle position switch and throttle position sensor
(TPS).


BASIC IDLE SPEED ADJUSTMENT
NOTE
(A) The basic idle speed has been factory-adjusted with the
speed adjusting screw (SAS) and does not normally require
adjustment.

(B) If the adjustment is required, first check that the ignition
plug, injector, ISC servo, and compression pressure are
normal.

(1) Before starting the inspection and adjustment procedures,
set the vehicle in the following conditions:
*Engine coolant temperature: 80 to 95°C (176 to 205°F)
*Lights, electric cooling fan, accessories: OFF
*Transaxle: Neutral (P range on vehicles with automatic
transaxle)
*Steering wheel: Straightforward position

(2) When using the multi-use tester, connect it to the diagnosis
connector.
NOTE
The connection of the multi-use tester grounds the selfdiagnosis/
data transmission selector terminal.
(3) When not using the multi-use tester, proceed as follows:
*Insert a paper clip into the l-pin blue connector
*Connect a primary-voltage-detecting tachometer to the
paper clip.
NOTE
The tacho/neter should read l/3 of the actual engine
speed. This means that the actual engine speed is the
tachometer reading multiplied by 3.
*Using a jumper wire, ground the self-diagnosis/data
transmission selector terminal (terminal 10) of the
diagnosis connector (white).

(4) Remove the waterproof female connector from the ignition
timing adjusting connector (brown).

(5) Using a jumper wire, ground the ignition timing adjusting
terminal.

(6) Start the engine and run at idle.

(7) Check the basic idle speed.
When using the multi-use tester, select item No. 38 and
read the idle speed.
Basic idle speeci: 700 + 50 rpm

NOTE
(A) The engine speed may be low by 20 to 100 rpm while
the vehicle is new [distance driven approx. 500 km (300
miles) or less], but no adjustment is necessary.
(B) If the engine stalls or speed is low despite a sufficient
distance driven [approx. 500 km (300 miles) or more], it
is probably due to deposits on the throttle valve. In this
case, clean the throttle valve.

(8) If the basic idle speed is out of specification, adjust by
turning the speed adjusting screw (SAS).

NOTE
If the idle speed is higher than the standard value even with
SAS fully tightened, check to see if there is evidence of the
idle switch (fixed SAS) being moved. If the idle switch
seems to have been moved, adjust it. If it does not seem to
have been moved, there may be a leak caused by
deteriorated fast idle air valve (FIAV). In such a case, replace
the throttle body.

(9) Turn the ignition switch OFF.

(lO)When the multi-use tester has not been used, remove the
jumper wire from the self-diagnosis/data transmission
s e l e c t o r t e r m i n a l .

(11)Remove the jumper wire from. the ignition timing adjusting
terminal and replace the connector back again.

(12)Start the engine again and run at idle for 10 minutes to
make sure that the engine runs at proper idle speed.

that is for the TPS

This should work for your 2.6l Astron II as well.

ADJUSTMENT OF IDLE POSITION SWITCH AND
THROTTLE POSITION SENSOR (TPS)
(1) Disconnect the throttle position sensor connector.

(2) Using jumper wires, connect an ohmmeter across terminal
3 (idle position switch) and terminal 4 (sensor ground) of
the throttle position sensor.

(3) Insert a 0.65-mm-thick feeler gauge between the fixed SAS
and throttle lever.

(4) Loosen the throttle position sensor mounting bolts and turn
the TPS body fully counterclockwise.

(5) In this condition, check that there is continuity across
terminals 3 and 4.

(6) Slowly turn the throttle position sensor clockwise until you
find a point at which there is no continuity across terminals
3 and 4. Then, tighten the throttle position sensor
mounting bolt securely.

(7) Connect the throttle position sensor connector.

(8) When using the multi-use tester, connect it to the diagnosis connector.

(9) When not using the multi-use tester, proceed as follows:
*Disconnect the throttle position sensor connectors and
connect the special tool, Test Harness Set, between
the disconnected connectors.
*Connect a digital voltmeter between the throttle position
sensor terminal 2 (sensor output) and teminal 4 (sensor ground).

(lO)Turn the ignition switch ON (but do not start the engine).

(11) Check the throttle position sensor output voltage.
When using the multi-use tester, select item No. 14 and
read the throttle position sensor output voltage.
Standard value: 400 - 1,000 mV

(12)lf the voltage is out of specification, check the throttle
position sensor and associated harnesses.

(13)Remove the feeler gauge.

(14)Turn the ignition switch OFF.


ADJUSTMENT OF FIXED SAS

(A) The fixed SAS has been factory-adjusted. Never attempt to
move it.

(B) Should it be out of proper adjustment, adjust by following
the procedure given below.

(1) Sufficiently slacken the accelerator cable.

(2) Loosen the lock nut on the fixed SAS.

(3) Sufficiently loosen the fixed SAS by turning it counterclockwise
to fully close the throttle valve.

(4) Tighten the fixed SAS slowly to find a point at which it
contacts the throttle lever (where the throttle valve starts
opening). From that point, tighten the fixed SAS further 1 l/4
turns.

(5) Holding the fixed SAS to prevent it from turning, tighten the
lock nut securely.

(6) Adjust the accelerator cable tension.

(7) Adjust the basic idle speed.

(8) Adjust the idle position switch and throttle position sensor
(TPS).


BASIC IDLE SPEED ADJUSTMENT
NOTE
(A) The basic idle speed has been factory-adjusted with the
speed adjusting screw (SAS) and does not normally require
adjustment.

(B) If the adjustment is required, first check that the ignition
plug, injector, ISC servo, and compression pressure are
normal.

(1) Before starting the inspection and adjustment procedures,
set the vehicle in the following conditions:
*Engine coolant temperature: 80 to 95°C (176 to 205°F)
*Lights, electric cooling fan, accessories: OFF
*Transaxle: Neutral (P range on vehicles with automatic
transaxle)
*Steering wheel: Straightforward position

(2) When using the multi-use tester, connect it to the diagnosis
connector.
NOTE
The connection of the multi-use tester grounds the selfdiagnosis/
data transmission selector terminal.
(3) When not using the multi-use tester, proceed as follows:
*Insert a paper clip into the l-pin blue connector
*Connect a primary-voltage-detecting tachometer to the
paper clip.
NOTE
The tacho/neter should read l/3 of the actual engine
speed. This means that the actual engine speed is the
tachometer reading multiplied by 3.
*Using a jumper wire, ground the self-diagnosis/data
transmission selector terminal (terminal 10) of the
diagnosis connector (white).

(4) Remove the waterproof female connector from the ignition
timing adjusting connector (brown).

(5) Using a jumper wire, ground the ignition timing adjusting
terminal.

(6) Start the engine and run at idle.

(7) Check the basic idle speed.
When using the multi-use tester, select item No. 38 and
read the idle speed.
Basic idle speeci: 700 + 50 rpm

NOTE
(A) The engine speed may be low by 20 to 100 rpm while
the vehicle is new [distance driven approx. 500 km (300
miles) or less], but no adjustment is necessary.
(B) If the engine stalls or speed is low despite a sufficient
distance driven [approx. 500 km (300 miles) or more], it
is probably due to deposits on the throttle valve. In this
case, clean the throttle valve.

(8) If the basic idle speed is out of specification, adjust by
turning the speed adjusting screw (SAS).

NOTE
If the idle speed is higher than the standard value even with
SAS fully tightened, check to see if there is evidence of the
idle switch (fixed SAS) being moved. If the idle switch
seems to have been moved, adjust it. If it does not seem to
have been moved, there may be a leak caused by
deteriorated fast idle air valve (FIAV). In such a case, replace
the throttle body.

(9) Turn the ignition switch OFF.

(lO)When the multi-use tester has not been used, remove the
jumper wire from the self-diagnosis/data transmission
s e l e c t o r t e r m i n a l .

(11)Remove the jumper wire from. the ignition timing adjusting
terminal and replace the connector back again.

(12)Start the engine again and run at idle for 10 minutes to
make sure that the engine runs at proper idle speed.

that is for the TPS

oooooor just get a screwdriver and turn the idle up :P

oooooor just get a screwdriver and turn the idle up :P

lol no, you didnt read his post properly.

He moved the stop throttle screw which is a baaaaad thing.

Thanks very much to all those responded, particularly to Killbilly for the detailed adjustment instructions.

Since you probably don't have the diagnostic harness in your top draw, back-probing the wires with the multimeter will get your output voltages. Can't begin to go into the number of TPS' I've reset.... :doubt: