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Discussion Starter #1
Hey Everyone!

New here! Quick backstory, I bought a 1986 300zx (VG30E) as a daily driver/project car. I'm not the most mechanically inclined but am willing to try things to make this work. Your guys' input would be definitely appreciated!

The problem(s):

1. Car has trouble actually starting, while cranking it ?spudders? and has a difficult time actually starting when cold starting.

2. Every time I start the car my windshield wipers go on then stop after about 3 wipes.

3. Lastly (that I can think of at the moment) and more importantly, No matter if the car is in "Park" or "Drive" it can rev to 2500RPM and then it drops back down and starts over again. The car doesn't turn off it just drops and tries again.

Located in SoCal if anyone is interested in wrenching or could hang out!
 

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It is very likely your car has multiple problems.
First get the Factory Service Manual (FSM) for you car year, FSMs at XenonZcar.com Spend a little time and get familiar with the FSM.
Next, section EFEC of the FSM is where you will be spending some time. The engine control system will need some TLC, and it is covered in this section. Perhaps start with the self diagnosis. Come back when you have questions.
 

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Number 1 seems like the cylinder temperature sensor:
The Easy Way to Change Your Cylinder Head Temperature Sensor(chts)​
The manual says to remove the timing belt and the backing plate to do this, but here is the easy way:
  1. First, locate the sensor, it is on the front face of the driver side head. Hard to see sometimes, look around.
  2. Remove spark plug wires from distributor cap and disconnect temp. sensor(this takes some time and frustration the first time) Also remove the engine driven fan. You need to loosen the tension on the alternator/water pump belt before you do this. Remove the 4 small bolts that hold the fan clutch onto the water pump and it slides right off with a little wiggling to free it.
  3. Take a really long straight edge screw driver, and stick it down into the engine from up top beside the distributor cap. You should be able to see the temperature sensor from this spot. Rest the screw driver on the temp sensor.
  4. Now the fun part: Get a big hammer and break off the plastic connector on the temp sensor. Carefull, it is fairly fragile, a small hammer will probably do also, but is not as much fun.
  5. A shallow socket will now fit over the temp sensor, with the back edge of the socket actually behind the timing belt cover. use the socket only to break the sensor loose, because if you screw the sensor all the way out, it will jam and the sensor and socket will be stuck behind the timing belt back plate, if this happens, simply screw the sensor back in until the socket can be removed. You can screw it the rest of the way out with your fingers, if it is dirty and difficult, use a pair of pliers, remember, you're throwing this part away. Once out, blow the hole out with air.
  6. The new sensor can be screwed firmly down with your finger tips, I usually put a layer or two of teflon tape around the threads to seal them, and it will be much easier to remove if you have to do it again. Do not put tape over the tip, which is where the sensor contacts the head.
  7. Now the tricky part: A deep well, 12 pt socket larger than the actual fitting on the sensor will fit cocked over the whole sensor, and will grip just tight enough to tighten the sensor down.
  8. Before you plug the sensor back in, remove the "sub harness" and inspect it. This is the short two conductor wire that goes from the temperature sensor and plugs into the engine harness by the front passenger side spark plug. Look just inside the connectors at the wires, they have a habit of breaking right here. If they are cracked/broken/whatever, make or buy a new "sub harness". You can cut the appropriate connectors for one off a wrecked car, the temperature sensor uses a standard injector connector and the other end, well, you can look around and find another one under the hood of a wreck. Wire them together and off you go. The sensor is a thermisistor, so the polarity of the wires doesn't matter.
 

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Discussion Starter #5
Thank you all for input.

@flyingt #1 solution may be out of my league but ill try and let you know if thats what it is. #3 sounds about right im I don't think it's a fuel related problem more of an electrical/air problem. I did however change the fuel filter and it seems like it has gained more power but still not going past 2500rpms (If that makes any sense?).

@thansen thank you for pointing out the FSM, I just wasn't sure where to really start but at least I narrowed it down to an electrical/air issue (hopefully).
 

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If the air flow meter goes bad, the car goes into limp home mode and won't rev past 2500, so this appears to be the problem here. One way to test this is to unplug the AFM and I bet the car runs the same whether plugged or unplugged.
 
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