How to properly adjust your idle

[Ghut300zx]

This is a very simple and quick adjustment. Minimal skill required.Takes 5 minutes.

Tools required:

First warm car up to operating temperature

Next turn engine off and remove keyDisconnect the AAC connector from the IACV (Idle Air Control Valve)seen here (yellow)

Start the engine and use the IACV adjustment screw to lower idle to 650rpm



Turn clockwise to lower RPM and counter-clockwise to raise RPM

Final step is to plug the AAC connector back in and your idle should rise and then settle to 750-800 rpm

Special thanks to Zwicked

[Zwicked]

Nice write-up and good photos

....and thanks for the mention!

[zxFarside]

NICE! Thanks for that.

[jona300zx]

so that is the recommended idle for a z??? mine usually idles at around 1000rpm.....is that bad??

[robomatic12]

Waste of gas and I'm sure it isnt good for your transmission

[jona300zx]

oh alright i guess I can add that to the 'to do' list

Thanks!

[lanceuppercut06]

kudos bro kudos

[es.biggs]

Thanks man, great write up

Your odometer is about to turn over!

[BWU300zx]

have to do this later. mines idles at like 1k. sometimes jumps up. guess i'll do it later. 5spd so it would be like revving it up anyways. but waste less gas i guess.

[93 Z32]

Nice right up. I'm idling at 900-1000 rpm. It drops to 800 when I put it in gear

Have 93 300zx NA automatic.
Have replaced injectors, ngk plugs, TPS, PTU sub harness, all new vacuum lines with the plenum coolant and vacuum bypass, and new Megan racing type2 catback & downpipes. Looks like the only thing I have left to do is adjust the iacv adjustment screw a lil bit

[kelseh]

I did this right after reading this post. I was idling low at like 600 rpm's. It would dim the lights and crap because the alternator didn't like running that slow. I did it exactly like the post says to and now I'm idling at around 850. Now it idles smooth.

[300ZXttZMAN]

I did this right after reading this post. I was idling low at like 600 rpm's. It would dim the lights and crap because the alternator didn't like running that slow. I did it exactly like the post says to and now I'm idling at around 850. Now it idles smooth.

Very nice glad you were able to search for the answer you needed.

Welcome to Nico!

[RealCarsHaveTorque]

This forum seems appropriate for my idle issue.

I have a 1994 300zx 2+2 w/ TT swap auto.

When it's in park the idle jumps from 500-1700 RPM
When I put it in reverse, if it doesn't die, it drops to 300rpm
When I'm at a stop light (so I'm just sitting there, chillin in drive) the idle jumps from about 500-1700, but it's so rough the car physically moves.

I had a bad ground wire so I paid Stan's Electric in Indy to replace all my wiring so i don't think it's electrical.
Could it be the MAF? (my buddy has a contour, autozone told him he needs a new MAF and coilpack)

At first, I was told that all my ignition coils were bad, well mechanic called me yesterday (same one who told my coils were bad) said that my coils were fine. But the one is cyl 5 I had replaced bc it was blown.

I think it's fuel bc I'm eating gas like crazy (8-11 mpg) but if I put injector cleaner in there I get about 16mpg.

so could it be injectors?
since it's misfiring, could it be as simple as spark plugs?
also, is there a difference between ignition coils & a coil pack?

I don't know, I'm at a loss at this point. I'm 16 and this is my dream car and I just wanna get it fixed, but it's kicking my a**.

any help is appreciated guys!

[samson123]

hello all, 1994 300zx manual, is it normal for the idle to rise in between shifts even if im not, giving it gas or taking it out of gear putting it in neutral,it rises above 1000 then immediatly comes back to normal?

[nexus08]

thought I'd bump this and ask a question.

So my Z idles around 1200 rpm in park, but in gear it is at around 800.

Should I adjust the idle down so that it is at 800ish when in park, or is it ok as is?

Thanks!

[emiliog2276]

thought I'd bump this and ask a question.

So my Z idles around 1200 rpm in park, but in gear it is at around 800.

Should I adjust the idle down so that it is at 800ish when in park, or is it ok as is?

Thanks!

You want the lower idle when it is in park you dont want it over 1000. I do think the idle is different when its a manual , i have an automatic but it should be printed on the label right under your hood.

[bones72751]

I just replaced my IAC with a used one from z1. Same as my old one, I set the idle to 650 but when I plug the connector back in, it does not raise? I have 12v at the connector. Any ideas?

[c_wood52]

This forum seems appropriate for my idle issue.

I have a 1994 300zx 2+2 w/ TT swap auto.

When it's in park the idle jumps from 500-1700 RPM
When I put it in reverse, if it doesn't die, it drops to 300rpm
When I'm at a stop light (so I'm just sitting there, chillin in drive) the idle jumps from about 500-1700, but it's so rough the car physically moves.

I had a bad ground wire so I paid Stan's Electric in Indy to replace all my wiring so i don't think it's electrical.
Could it be the MAF? (my buddy has a contour, autozone told him he needs a new MAF and coilpack)

At first, I was told that all my ignition coils were bad, well mechanic called me yesterday (same one who told my coils were bad) said that my coils were fine. But the one is cyl 5 I had replaced bc it was blown.

I think it's fuel bc I'm eating gas like crazy (8-11 mpg) but if I put injector cleaner in there I get about 16mpg.

so could it be injectors?
since it's misfiring, could it be as simple as spark plugs?
also, is there a difference between ignition coils & a coil pack?

I don't know, I'm at a loss at this point. I'm 16 and this is my dream car and I just wanna get it fixed, but it's kicking my a**.

any help is appreciated guys!

Did you ever get this solved? having the same issue on my manual tt.