94 gs300 i bought a used engine from a 93 sc300 and installed it in a 94 gs300.i only had to swap 1 sensor on the throttle body to fit my harness.engine starts up fine but it idles below 500 rpm.when i throttle to 100%,it still idles below 1000.i have strong spark but i also have an engine light that i have not checked

Test the map and tps. If the throttle is controlled electronically, also test the accelerator position sensor. Make sure the tps signal changes smoothly as the throttle is opened.

Manifold Absolute Pressure (MAP) Sensor
OPERATION The Manifold Absolute Pressure (MAP) sensor is a device which monitors manifold vacuum. It is either mounted on the firewall or throttle body and is linked electrically to the on-board computer. The MAP transmits information on manifold vacuum conditions to the computer. This data determines engine load and is used with data from other sensors to adjust the air/fuel mixture.
On the 2.5L engine, the MAP sensor is mounted in the right rear side of the engine compartment. It is connected to the throttle body by vacuum line. The MAP sensor on V6 and V8 engines is mounted to the throttle body. It is connected by an L-shaped rubber fitting. The V10 MAP sensor is found on the right side of the intake manifold and senses vacuum in the manifold.
TESTING See Figure 1
To completely test this sensor and its circuitry, you will need a DRBII scan tool, or equivalent. This is a test of the MAP sensor only. This test is for all engines except the 4-cylinder.
On the V6 and V8 engines: inspect the rubber fitting from the MAP sensor to the throttle body. Repair if necessary.On the V6 and V8 engines: test the MAP sensor output voltage at the connector between terminals A and B (see drawing). With the ignition ONand the engine OFF , the output voltage should be 4-5 volts.Test the engine controller terminal No. 1 for the same voltage to confirm that the wiring is in good shape. Repair if necessary.Test the MAP sensor voltage at the sensor connector between terminals A and C with the ignition ON . The voltage should be 4.5-5.5 volts. Also check terminal No. 6 of the engine controller wiring harness for the same voltage. Repair or replace the wiring as necessary.Test the engine controller pin-1 for the same voltage to verify the wire harness condition.
Fig. 1: Terminal connections for testing the MAP sensor


Throttle Position Sensor (TPS)
The Throttle Position Sensor (TPS) is located on the throttle body and tells the computer when the engine is at idle, off-idle, or at Wide-Open Throttle (WOT). At idle, the computer cancels the spark advance. Idle speed is computer-controlled through the automatic idle speed motor.
TESTING To completely test this sensor and circuitry, you need the DRBII scan tool, or equivalent. This is a test of the sensor only. This test applies only to V6, V8 and V10 engines.
This test requires a digital voltmeter. The sensor must be checked on the vehicle with its 3-wire connector engaged to the sensor. The center terminal wire of the sensor connector is the output terminal.
Remove the air cleaner housing.Attach the positive lead of the voltmeter to the center terminal of the sensor harness.Attach the negative lead of the voltmeter to a good ground.With the ignition key in the ON position and engine not running, check the sensor output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at Wide Open Throttle (WOT). At idle, the sensor output voltage should be greater than 200 millivolts. At WOT, the sensor output voltage should be less than 4.8 volts. The output voltage should increase gradually as the throttle plate is slowly opened from idle to WOT.If the sensor does not meet specifications, replace it.

Fig. 1: Common TPS mounting-V6 and V8 engines




Fig. Fig. 2: Common TPS mounting-V10 engine

images for Where is crankshaft sensor location on 95 ...

eplaced engine on '97 SC300 now new engine does not have Crank ...

www.clublexus.com/.../633233-replaced-engine-on-97-sc300-now-new-...

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Lexus Crank Position Sensor ' LS400 SC300 ES300 GS300 ...

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Products 1 - 10 of 68 - 95 1995 Lexus LS400 Crank Position Sensor Denso NLA 7/13 ... 96 1996 Lexus SC300 Crank Position Sensor Denso Includes Pigtail.

Clearing the codes is simple that is done by removing the fuse of the EFI from junction box 2 for 10 seconds. Make sure to remove the jumper wire and switch the key off before clearing the codes.

Here are some common Lexus vehicles 1990-1995 codes:

Code 12 and Code 13 Rpm signal circuit fault
Code 14 Igniter signal circuit fault
Code 16 ECT control signal fault
Code 21 and Code 28 Main oxygen sensor fault (for ES300; SC300 & GS300 models)
Code 22 Coolant temperature circuit fault
Code 24 Intake temperature sensor circuit fault
Code 25 and Code 26 Air fuel ratio fault (for ES300 & SC300 models)
Code 27 Sub-oxygen sensor circuit fault (for ES300 CA & GS300 models)
Code 31 Low airflow meter voltage (for ES300 and GS300 models)
Code 32 High airflow meter voltage (for ES300 model)
Code 35 Barometric pressure sensor circuit fault (for GS300 & SC300 models)
Code 41 and Code 47 Throttle position sensor circuit fault
Code 42 Vehicle speed sensor circuit fault
Code 43 Starter signal
Code 51 Switch condition signal fault (for ES300; GS300 & SC300 models)
Code 52 Code 52 and Code 55 Knock sensor circuit fault
Code 71 EGR system circuit fault (for ES300; GS300 & SC300 models)
Code 78 Fuel pump control circuit fault (for GS300 & SC300 models)

It could be a few things. 1. Clogged fuel filter, or maybe a throttle position sensor with a bad spot. Or a fuel pressure problem

If you need further help, I’m available over the phone at https://www.6ya.com/expert/edward_020b3320326d263d

Your 94 engine has separate coolant temp sensor and gauge sender. The 96 engine incorporates both in the engine coolant temp sensor. The coolant temp sensor is near the t-stat, below the throttle body. Check to see how many wires are in this plug. If it only has two, you may be able to use the plug from the 96 motor and wire it into the wire where the original sensor was. You should be able to just color match. Not sure if you can get away with this but the 96 plug should have a third wire, and it's woth a try.

Hi, I recommend you test the MAP sensor. Procedure is listed below. If the Jeep cuts out when accelerating, this is the usual problem.

2.5 liter engine MAP sensor:

4.0 liter engine MAP sensor:

TESTING
See Figures 3 and 4






Fig. Fig. 3: Wiring harness connector terminal identifications for the MAP sensor harness side. Terminal 1 (left), terminal 3 (right)



Fig. Fig. 4: Performing a voltage test with a digital voltmeter on the harness side of the MAP sensor


1. Backprobe with a high impedance voltmeter at MAP sensor terminal Nos. 1 and 3.
2. With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
3. If the voltage is not as specified, either the wiring to the MAP sensor or the PCM may be faulty. Correct any wiring or PCM faults before continuing test.
4. Backprobe with the high impotence voltmeter at MAP sensor terminal Nos. 1 and 2.
5. Start the vehicle and verify that the sensor voltage is 0.5-1.8 volts with the engine at a normal idling speed.
6. Verify that the sensor voltage reaches 3.9-4.8. volts at Wide Open Throttle (WOT).
7. If the sensor voltage is not as specified, check the sensor and the sensor vacuum source for a leak or a restriction. If no leaks or restrictions are found, the sensor may be faulty.




Removal & Installation




1. If the MAP sensor is mounted on the front of the throttle body, the throttle body must first be removed from the engine.
2. If the sensor is mounted on the side of the throttle body, the intake air tube must first be removed.
3. Remove the two sensor mounting screws and carefully pull the sensor away from the throttle body. Be careful not to lose the rubber L-shaped fitting that attaches the sensor to the throttle body.

To install:

1. Install rubber L-shaped fitting to the sensor.
2. Place the sensor into position being careful to guide the fitting onto the throttle body nipple.
3. Install the sensor mounting screws. Tighten the screws to 25 inch. lbs. (3 Nm).
4. Install the intake air tube or the throttle body as necessary.

you may have to get the new engine harners wires and pcm form the 94 model, that will sove your problem

Knock sensors are small, metal objects that detect prignition be fore it happens and cut fuel to the motor for a split second the keep it from destroying itself. (very important on turbocharged cars=melted pistons can result)
The leads are attached to the engine harness. Unscrew your bad sensor, put some teflon tape or paste on your new sensor and install by hand, then tighten with the correct wrench. Plug in the harness plug.

I wanted to start a thread specifically about failures within the throttle body concerning the GS300 (1998 in my case)

My symptons were:
VSC, VSC OFF, and ENGINE Lights would come on, followed by my car going into Limp Mode, where only that last 25% (if that) of the throttle would respond (basically have to floor the pedal to even move at all).

During the mornings, or when the engine was COLD, the throttle operated normal...then once the car warmed up, usually at about 10 mins, the problem would start...it happened intermitantly at first...1 or 2 days over the course of a week, then it became more consitent, until last week it became a daily problem.

The first part I tried was the Throttle Position sensor, which is on the front side of the throttle body, and the easiest thing to replace...this didnt help at all. $300 part from Lexus, $80 part from RockAuto.com (exacly same part toyota OEM)

THE PART THAT FIXED THE PROBLEM:
===========================================
"Idle Valve Motor", which is the larger electrical object next to the TPS on my 98 GS300. Problem is solved.

The Codes I got were P1120 and P1121 - Accelerator Sensor problem. However it wasnt really the Accelerator Sensor, it was indeed to actual electrical Motor that controls the opening of the Butterfly valve inside the Throttle body.

I found the problem by good old trouble shooting, and using an ohm meter to see if the throttle electric motor was getting elev, I found that the elec motor just to the left of the TPS was basically freaking out and shutting down. The Accelerator Pedal Sensor is on the Back-side of the throttle body where the throttle cable connects to, and has a spring on it. It was fine.

GS300's are indeed "drive by wire" concerning the throttle...the cable triggers the Accel Pedal Sensor, which sends a signal to the ECU, the ECU then sends power to the Idel Valve Elec Motor (next to the TPS), which opens and closes the mechanical butterfly valve, then the TPS sensor detects how far the elec motor is actually opening the butterfly valve...its a closed-loop feed-back system, meaning any failure in any sensor will cause the entire systm to fail.

The throttle cable apparently is ONLY there to allow the fail-safe of having that last 10-25% throttle when the electronic system fails...there is a gearbox inside the throtle body which allows the tail end of the throttle to manually engage the butterfly valve...the rest of the time, the butterfly valve is 100% opened and closed via the idle control motor.

As long as they are the same type of engine ( I believe they should both be 1.0L 3 cyl engines). Most parts for the Geo Metro from 1992 to 1994 interchange with out a problem.