no fuel?

[HeWhoKillz]

I have an 85 nissan 300zx turbo 5 speed. This may not even be fuel related. When the car is first started and driven after the first couple of minutes it starts to get these moments where it seems like the gas is totally cut off from the vehicle. The car does not miss out or anything but pushing on the accelerator literally gets you no where. Ill be driving at 35mph and the engine will cut out like I just lifted off the accelerator. Is this a fuel problem? I have in fact changed the fuel filter. I have a video but I don't know how much it might help. I was suggested the voltage regulator.

http://www.youtube.com/watch?v=J_66e4RkVm4

[MagicRat]

I think you're on the right track here. My thoughts would be a weak fuel pump or a bad fuel pressure regulator. A check of the fuel pump pressure, especially when its lost power, would be handy.

[shorod]

So from what I could see, the symptoms do seem consistent with an ignition-related misfire. It sure appeared that as you get higher in the revs the power seemed to come back, but when under load at low engine speed it wants to misfire.

How recently have you changed the spark plugs and plug wires? Does this use a pickup coil in the distributor, or is it distributorless? Have you ever noticed the tachometer jump around erratically? The symptoms you show are pretty consistent with what Fords of that vintage would do when the ignition module was failing. One symptom of those is from time to time the tachometer would jump around.

-Rod

[HeWhoKillz]

It has a distributor. Next time it goes for a cold start drive Ill watch the tach while its doing that. The only time I remember it bouncing wildly is when you first take at whether its hot or cold. Until you hit 10 or 15 mph the tach bounces up and down quite a bit.

[vgames33]

The Z31 uses a distributor with a CAS under the rotor. The tach signal is pulled from the coil.

Do you still have a code for the TPS?

[curtis73]

I'm going with the ignition camp here. Usually if the fuel delivery is in adequate you would get popping out the intake and when you floored it you would hear kind of a "woooaaaah" sound. Usually (I repeat: usually) starving for fuel doesn't cause that violent bucking. That is more typically associated with ignition.

[HeWhoKillz]

Originally Posted by vgames33

The Z31 uses a distributor with a CAS under the rotor. The tach signal is pulled from the coil.

Do you still have a code for the TPS?

I have code 11:Crank angle sensor/circuit

I have attempted to change the TPS and that did not affect anything.

[shorod]

Yep, that code 11 for a crank angle sensor would point to an ignition misfire as what you're experiencing. Sounds like you need to figure out if that's a crankshaft position sensor or pickup coil in the distributor.

-Rod

[vgames33]

Its a crank-angle sensor, sort of like the opti-spark. Uses LEDs and a slotted wheel. Its inside the distributor, under the rotor. Should be replaceable without removing the distributor. Do some reading, I hear that lots of Nissans use the same part, so you shouldn't have much trouble finding one in a local yard.

Check out the wiring harness going to the CAS. A Z I bought years ago ran like crap because the harness was pinched under the intake manifold. It would idle OK, but wouldn't rev much past 3k and had no power whatsoever.

[HeWhoKillz]

Originally Posted by vgames33

Its a crank-angle sensor, sort of like the opti-spark. Uses LEDs and a slotted wheel. Its inside the distributor, under the rotor. Should be replaceable without removing the distributor. Do some reading, I hear that lots of Nissans use the same part, so you shouldn't have much trouble finding one in a local yard.

Check out the wiring harness going to the CAS. A Z I bought years ago ran like crap because the harness was pinched under the intake manifold. It would idle OK, but wouldn't rev much past 3k and had no power whatsoever.

Well according to my Haynes book, the very first step is to remove the distributor. The CAS must be underneath it.

[shorod]

I wonder if the Haynes book just means the "distributor cap". Or maybe removing the entire distributor makes it easier to access the CAS, but as Vgames mentions, it's still possible to replace without pulling the whole distributor. I have never seen Haynes provide a risk assessment table for things like pulling the distributor so you can work on it on a bench versus leaving the distributor in the car and having an alternator poke you in the ribs while you lay across the engine to access it.

-Rod

[HeWhoKillz]

Originally Posted by shorod

I wonder if the Haynes book just means the "distributor cap". Or maybe removing the entire distributor makes it easier to access the CAS, but as Vgames mentions, it's still possible to replace without pulling the whole distributor. I have never seen Haynes provide a risk assessment table for things like pulling the distributor so you can work on it on a bench versus leaving the distributor in the car and having an alternator poke you in the ribs while you lay across the engine to access it.

-Rod

Luckily its impossible to get poked by the alternator because its at the bottom XD And the distributor is at the front of the engine at the top with easy access.

[vgames33]

My 85 service manual doesn't tell you how to change it, but it appears to be a simple job with the cap and rotor off. Looks like the signal wheel and the actual sensor are separate parts. The manual says to check for dirt or damage in the pickup wheel before changing the sensor itself.