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I pulled the codes from the ECU last night and well I need some help where to start on the problems. The codes where 11,12,21,23,41 anyone can poiint me where to start to fix those. Thanks alot....
 

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♣300zx♣ said:
I pulled the codes from the ECU last night and well I need some help where to start on the problems. The codes where 11,12,21,23,41 anyone can poiint me where to start to fix those. Thanks alot....
Did you read the sticky on ECU fault codes? You may also wish to D/L the FSM or get a Haynes to determine where the problems lie.
 

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11: crank angle sensor or circuit That would be the distributor, or the wiring

12: Air flow meter or circuit That would be the MAF, or the wiring

21: Ignition signal I beleive thats also part of the distributor, or possibly the ECU itself.

23: idle switch circuit That's part of the throttle position sensor assembly. Replacement is the only way to fix the problem.

41: Air temp sensor or circuit That's part of the MAF, as I recall. replacement is the only way to fix that problem.

EDIT: ^^^^^ On #41, I don't know if your car is an 84 or an 85 and later, the code placement changes for the later cars: The fuel temp sensor/circuit is located on the fuel pressure regulator, which is right on the front of the upper intake plenum.

Sounds to me, since all these problems are on the same side (driver side) of the car, that there may be some bad/broken wiring. Check connections and continuity before you start replacing any parts.....
 

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23: idle switch circuit That's part of the throttle position sensor assembly. Replacement is the only way to fix the problem.
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Why would replacement be the only option? It should be troubleshot with a multimeter for continuity. There is an adjustment at idle.

The TPS is just a switch that sends a signal that the car is at idle. As soon as you touch the throttle, the switch changes state.

On auto tranny cars, there is also a switch at full throttle as well as this idle throttle position. Some stick cars guys install a auto TPS so they can use this full throttle position switch for things like NO2, etc.
 

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Crowbar60 said:
Why would replacement be the only option? It should be troubleshot with a multimeter for continuity. There is an adjustment at idle.

The TPS is just a switch that sends a signal that the car is at idle. As soon as you touch the throttle, the switch changes state.

On auto tranny cars, there is also a switch at full throttle as well as this idle throttle position. Some stick cars guys install a auto TPS so they can use this full throttle position switch for things like NO2, etc.
There's more than one type of TPS, depending on the year of the car. One is the older switch type, one is the sweeping resistance change type. TPS units are solid state, as such any malfunction requires replacement.
 

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Crowbar60 said:
Thats really really funny. TPS are solid state? Oh my God!!!! You made my day. I am an Electrical Engineer. I have troubleshot dozens of these items from all types of Nissans. I have the 1988 FSM for 300zx and it makes no mention of a rotary pot on any VG30e or VG30et engines.

Some Nissan engines DO use a rotary pot in addition to a throttle position SWITCH (take one apart and find me the solid state device?). In fact, I adapted one to use on my vg30e (see the throttle body thread here). Its from a non-vg30e engine. A KA24e to be precise.

While I am 100% certain they are not solid state (do you know what that means?), I am nearly certain that potentiometer type throttle position devices are not used on 1984-1989 300zx cars.
Solid state to me means a unit that cannot be disassembled and the components inside repaired or adjusted. If it means something different to you, that's fine.
 
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