Accelerating issues and black smoke

Hi and thanks for using 2CarPros.

Black smoke usually indicates a rich fuel mixture (too much gas to the engine). With that in mind, I first suggest testing the fuel pressure to make sure the regulator is working and not allowing too much pressure to build.

Here are the pressure specs:

FUEL PRESSURE:

At Idle .................... 33 - 37 PSI (226 - 265 kPa)

At WOT .................... 38 - 44 PSI (265 - 304 kPa)

Here is a link that shows how that is done:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If the pressure is good and everything is working properly, my next suspect is the coolant temperature sensor. I am assuming that this vehicle is the same as the 4runner in the US. I am basing this information on that vehicle with the 4 cyl 2.4L.

Now, the coolant temperature sensor is used by the ECU to determine air fuel ratios. The computer adds or removes fuel based on coolant temperature. If the sensor is telling the computer the coolant is -40 degrees F but in reality it is 90 degrees F, the fuel mixture will be too rich (too much gas) and cause driveability issues and often times, black smoke.

Take a look through this link

https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor

With that in mind, here is a link that shows how to retrieve diagnostic trouble codes from your vehicle's computer.

https://www.2carpros.com/articles/toyota-trouble-code-definitions-and-code-gathering-method-1990-1995

If you follow the link, you may or may not end up with information related to this problem. I say that because most times, the computer doesn't realize it is receiving bad information from the sensor so it doesn't identify it as a problem. Regardless, check it to make sure nothing else is indicated.

If you find that is the problem, here are the directions for testing the sensor.

COMPONENT INSPECTION
1. Disconnect the connector from the Water Temperature Sensor.
2. Using an Ohmmeter, measure the resistance between the terminals.
Testing Water Temperature Sensor

See picture 1

3. Refer to the specification chart and compare readings with appropriate temperature parameters.
Water Temperature Sensor (THW)

See picture 2

4. If readings are not as specified, replace the Water Temperature Sensor.

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Here are a couple links that may help you.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

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Next, if the sensor is bad, here is a link that shows in general how one is replaced.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

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Let me know if this helps or if you have other questions.

Take care,
Joe

Hi and welcome back:
If the sensor is broken, replace it. And yes, it could start when warmed up because the mixture is too rich. When cold, it requires a richer mixture to run. When it gets warm, the mixture should lean. If it doesn't, it will run too rich.

Hi and welcome back:

Yes, it does have one. It is mounted on the fuel rail. There will be a vacuum hose going to it. Remove the vacuum hose and confirm there is no fuel smell or evidence of fuel in the vacuum hose. If there is, it is drawing raw fuel into the engine via the vacuum hose and will cause a rich mixture. If you find the regulator is bad, here are the directions for replacement. Note: Picture one shows the regulator.

1. Disconnect the vacuum sensing hose.
Fuel Pressure Regulator And Hoses

See picture 1

2. Put a suitable container under the FPR to catch any fuel that escapes.
3. Remove the No.1 EGR pipe.
4. Loosen the hose clamp and remove the fuel return hose from the FPR.
5. Loosen the lock nut between the FPR and the fuel rail.
Removing The Fuel Pressure Regulator (FPR)

See picture 2

6. Unscrew the FPR from the fuel rail.

INSTALLATION:

1. Fully loosen the lock nut on the FPR and install a new O-ring.
2. Insert the FPR into the fuel rail, giving attention to the proper positioning of the pressure regulator.
3. Torque the lock nut to 22 ft. Lbs. (29 N-m).
4. Reconnect the fuel return line.
5. Using a new gasket, reinstall the No.1 EGR pipe.
6. Reconnect the vacuum sensing hose to the FPR.
7. Ensure that any gasoline that escaped is thoroughly cleaned from the engine.
8. Start the engine and check for fuel leaks.

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Let me know if this helps.

Joe

Hi and welcome back:
The throttle position sensor (TPS) could be an issue. The TPS sends a varying voltage signal to the ECU based on throttle valve position. The ECU can then adjust fuel delivery based on acceleration, deceleration, full throttle, or idle.

The TPS is adjustable. Here are the directions for adjusting and making sure it is where it should be. The attached pictures correlate with these directions.

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1. Loosen the two set screws that secure the TPS to the throttle housing. (DO NOT REMOVE THE SCREWS)
TPS Adjustment Screws

See Picture 1

2. Connect an Ohmmeter to terminals IDL and E2 of the TPS after removing the connector.
3. Insert a 0.70mm (0.028in.) Feeler gauge between the throttle stop screw and stop lever.
Checking TPS Adjustment

See Picture 2

4. Rotate the TPS counter-clockwise and slowly back clockwise until the Ohmmeter just looses continuity, (infinite ohms).
Adjusting TPS

See Picture 3

5. Secure the TPS with the two set screws.
6. Remove the feeler gauge and recheck TPS setting.
7. There should be continuity with a 0.57mm (0.022in.) Feeler gauge inserted in the stop. There should be NO continuity with a 0.85mm (0.034in.) Feeler gauge inserted in the stop.
8. Remove the Ohmmeter and reconnect the TPS connector.
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Let me know if this helps.

Joe

Welcome back:
Anything is possible. However, make sure there are no engine vacuum leaks that can act the same.

Hi:
Here are the directions for testing the coil as well as the specifications.

1. Connect one end of an ohmmeter to the (-) side of the ignition coil. Connect the other end to the (+) side of the ignition coil.

Primary Coil Test
See pic 1

Primary Resistance (Cold): 0.5 - 0.7 ohms

1. Connect one end of an ohmmeter to the high tension terminal of the ignition coil. Connect the other end of the ohmmeter to the (+) side of the ignition coil.

Secondary Coil Test
see pic 2

Secondary Resistance (Cold):11.4k - 15.6k ohms

2. If Primary or Secondary coil resistance value is not within specifications, replace ignition coil. For further information, refer to SPARK TEST.

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Pic 3 is the resistance specs.

Let me know what you find. I have to be honest, I really feel this has something to do with fuel pressure because of the black smoke you indicated. Have you confirmed fuel pressure and checked the regulator?

Let me know,
Joe