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Discussion Starter #21
more driving, just local, but when the engine is warm, and with a light foot, it runs fine. CEL clears. any time i put the pedal down, it will lose power. Added a 20oz techron to it tonight since it still has 7/8 tank left.
 

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Mambeau / Admin
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more driving, just local, but when the engine is warm, and with a light foot, it runs fine. ...
Does this mean it misbehaves when the engine is warm and you use a 'heavier' foot on the gas?

I was starting to think engine temp might be a clue, but it can't be if the misbehavior occurs under all temps.

If a warm engine made everything OK all the time I might suspect there's an issue with the Engine Coolant Temp (ECT) sensor - the one that signals the ECM, not the one that signals the temp gauge in the cluster.
 

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Discussion Starter #23 (Edited)
Its still misfiring at all temps, but the only time i can get it to run normal is when the engine is up to temp and with a light foot. Could the previous thermostat failure cause damage to the ECT? Its a $17 part.
 

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Mambeau / Admin
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Thanks for that clarification ...

It tends to rule out ECM confusion over the engine temp, but it still doesn't narrow things down any further than 3 big items:

- fuel
- spark
- ECM control and coordination (which also involves all the sensors)
 

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Discussion Starter #26
4 new injectors on the way..
I think the only thing i missed in my previous post procedure-wise was to pull the fuel pump fuse then turn it over to relive the pressure. then disconnect battery and take things apart.
 

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Discussion Starter #27
Will removing the throttle body require any replacement gaskets? Seems to be the only hard part.


  1. Relieve the fuel system pressure.
  2. Remove the throttle body
  3. Tag the fuel injector electrical connectors for identification to their original locations. Detach the four fuel injector electrical connectors, the Crankshaft Position (CKP) sensor connector, and the Knock Sensor (KS) connector.
  4. Detach the DLC1 diagnostic connector and wire clamp from the brackets.
  5. Disconnect the vacuum line from the fuel pressure regulator. Detach the fuel return hose from the pressure regulator.
  6. Remove the union bolt and gaskets and disconnect the fuel inlet pipe from the fuel rail (delivery pipe). Expect fuel to run out. Place clean shop cloths under the fuel inlet and loosen the bolt slowly.
  7. Remove the two fuel rail hold-down bolts and remove the fuel rail with the injector still attached. The injectors are only retained by their O-rings and will tend to drop out of the fuel rail, so use care. Remove the four insulator from the four spacers.
  8. Pull out the injectors from the fuel rail. Discard the O-ring and grommet from each injector.

To install:

  1. Install new grommets on each injector, and then lubricate the new O-rings with a light coat of gasoline. Install the O-rings to the fuel injectors.
  2. While turning the injector left and right to ease it into place, install it to the delivery pipe. Install all four injectors.
  3. Position the injector connector upward. Place the new insulators and spacers in position on the intake manifold.
  4. Temporarily install the bolts holding the delivery pipe to the intake manifold.
  5. Check that the injectors rotate smoothly. If they do not, recheck the position of the O-rings, or replace them.
  6. Position the injector connector upward, then tighten the bolts holding the delivery pipe to the intake manifold to 15 ft. lbs. (21 Nm).
  7. Attach the injector connectors taking note of the identification tags made at removal.
  8. Install the fuel inlet pipe with new gaskets; tighten the union bolt to 22 ft. lbs. (29 Nm) and the bolt to 14 ft. lbs. (20 Nm).
  9. Install the fuel return pipe to the fuel pressure regulator. Connect the vacuum line to the pressure regulator.
  10. Attach all electrical connectors and vacuum lines, as required.
  11. Install the throttle body
 

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Mambeau / Admin
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Will removing the throttle body require any replacement gaskets? Seems to be the only hard part. ...
Buried in the 2RZ / 3RZ throttle body removal procedure is a note to use a new gasket at the time of installation.
 

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Fuel injectors can be replaced without taking apart the intake system. The rail can be unbolted and lifted away from each injector to get them replaced. Just don't drop the fuel rail spacers,aluminum banjo bolt washers, and lube the injector O rings with Vaseline so they slide in without getting pinched. Just be patient when doing it...beats having to replace all the gaskets though
 

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Discussion Starter #30
thanks, i'll try doing it without removing it but i bought the $2.36 gasket just in case. planning on a saturday work day assuming i get the injectors in time ($60 each - new denso).
I'll check the plugs too myself since i dont trust the dealer (says they were replaced Jan) but running it with a misfire anyway I should just replace them all anyway.
If I still get a 0303 code, i have to assume its a valve problem, right?
 

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If I still get a 0303 code, i have to assume its a valve problem, right?
Maybe invest in a compression gauge to verify? Since you did say the vehicle overheated...could be a bad head gasket


A P0303 just tells you the cylinder isn't firing properly.. and the blinking CEL means your converter is overheating from unburned fuel... meaning incomplete combustion or no spark
spark plug
ignition coil
ignition coil circuit
fuel injector
fuel injector circuit
ECU
low compression (valves, rings, head gasket)


Have you confirmed spark from the #3 coil? .. that would at least let you know that the circuits to the coil were good. You already swapped coils around with no change so we will assume the components are ok.
 

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Discussion Starter #32
The #3 coil wire disappears into a wiring harness so i can't follow it to check the other side. Is there a pin-to-pin multimeter test i can do on the wire clip?
 

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I can get access to a coil on plug tester friday..
Just remove the coil from the spark plug tube, reconnect the connector/harness insert a philipps screwdriver into the boot til it makes contact with the metal terminal inside, hold the insulated screwdriver handle and get the metal screwdriver shank about an 1/8th inch away from a good ground (pretty much anything metal on the engine). Have someone crank/start the motor and see if there is an arc from the screwdriver to ground.
Or..insert a known good spark plug into the coil and ground the metal spark plug body . Have someone start the motor and look for the spark across the spark plug electrode.
If you still are not confidant about the spark intensity, have someone hold the screwdriver shank with one hand and touch the intake manifold with the other. Crank the motor and see how high they jump. if they jump and curse at you, spark is okay.
Or you could just get the tester which is nothing more than a spark plug with a ground clip on it
 

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Honestly, instead of spending more money then it's worth, just buy another 2rz or do a motor swap.

I'm not saying this to cause a fuss (as I have an 03 2rz @ only 70k original miles) but sometimes it's easier to just replace the whole dang thing for less.

And in your spare time take it apart and learn what is what.
 

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Mambeau / Admin
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Factory spark plug spec's are:

Spark plug type: 2RZ–FE and 3RZ–FE engines

DENSO K16R–U11
NGK BKR5EYA–11

Spark plug gap, mm (in.):

1.1 (0.043)

If the NGK V-Power plugs need to be adapted by using a different gap for some reason I don't know what it is.
 

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Discussion Starter #38 (Edited)
I think I have a blown head gasket. I opened the oil cap and see some light colored (lighter than oil anyway) residue. Looks like coolant might be getting in. Engine is getting worse too. I guess i have to take it in to shop (dealer sucks here).
 

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Mambeau / Admin
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Sorry to hear it's something that major, but I have to agree the evidence is starting to point in that direction.
 

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Discussion Starter #40
I'm going to have it rebuilt, i dont think the block is cracked but i'll know more next week. I just got new tires, brakes, battery, so i'd like ot get 4-5 more years from it so i can save up more for a new one.
 
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