OK this does not happen all the time,but mainly when the car has been sitting for a wee while.

1.When i turn her over revs shoot up to about 1700 and bounce up and down between this and 700.

2.When i put her in gear revs drop below 400 and she cuts out,but if i leave her running for a few mins 8/10 times does not cut out,but revs still bounceing.

3.But i have notice that when i turn her over,i hear crackerling behind my dash,and this crackerling is in time with the revs bounceing,and if there is no niose 9/10 the revs are normal. :confused: :(

The car is a 92 import N/A

check sensor connections first for dirt and corrosion,

Check water temp sensor its just behind the rad( a yellow connector) take it out and clean it.

Also check tps the same or maybe it needs adjusting.

 

You sure that noise isnt an air leak? but it would be more or a hiss than a crackle. crackle could be a spark arking or something?

The "crackle" is the noise the stepper motor makes trying to control the engine RPM. Clean the idle air thingy at the back of the motor. Do a search on idle air.

The "crackle" is the noise the stepper motor makes trying to control the engine RPM. Clean the idle air thingy at the back of the motor. Do a search on idle air.

 

Where is the stepper motor on the vg30dett?

http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&slide=4&cycle=off&scale=0&design=default&total=190

and look for the IAA

??? Didnt think the zed had a stepper motor, it uses twin throttle cables.

 

Stepper motors are usually on wired pedal and throttle assemblies not cabled ones.

 

The black box on the throttle body is the tps not a stepper.

No not the throttle assembly, the idle air adjuster at the back of the intake manifold. It's used to bypass the butterflies to get the car to idle.

http://300zx-twinturbo.com/cgi-bin/manual.cgi?list=efec&dir=&config=&refresh=&direction=forward&scale=0&cycle=off&slide=17&design=default&total=190

See the IAA

Sorry, it's not a stepper motor, it's a solenoid which is PWM'd by the ECU

ahhh hibady hopady hip hop valve i know what ya talking bout now :) see its all so clear now :D

ahhh hibady hopady hip hop valve

That's the one - couldn't remember it's name :)

OK this does not happen all the time,but mainly when the car has been sitting for a wee while.

1.When i turn her over revs shoot up to about 1700 and bounce up and down between this and 700.

2.When i put her in gear revs drop below 400 and she cuts out,but if i leave her running for a few mins 8/10 times does not cut out,but revs still bounceing.

3.But i have notice that when i turn her over,i hear crackerling behind my dash,and this crackerling is in time with the revs bounceing,and if there is no niose 9/10 the revs are normal. :confused: :(

The car is a 92 import N/A

 

hi here, thanks guys for the response il will let you no how i get on.:D