In the past few days (since I joined this board actually) my Z has started to idle really strange, and at rpms high enough to absolutely kill my gas mileage. When you first start the car it idles normal for when it's cold, around 100rpm when it's warm, but when you put the car into gear it wants to idle about 1200-1500 adn in park it's anywhere from 1500-2500rpm. Most of the time when you put the car back into neutral the revs will pick up for a second, and then die back down to around 1000. I noticed this summer that it idled a lot higher in park than neutral, could this be a continuation of that? Not only is it driving me crazy it is using loads of gas, and at nearly $2 a gallon, I can't really afford that. Does anyone have a clue what's going on with this thing?

 

its to do with your transmission electronics....
when you shift a car, usualy it revs up a lil and then drops down when you put it in Drive...because there is a load on the enginine as soon as you shift to drive the car will increase idle, to compensate for the load...yours just increases it too much...i

 

Hey it's a long-shot but when I had the problem of idle. I adjusted the fuel-air micture screw. It should be the one that is vertical with a slotted end. Turn it clockwise, and or counter-clockwise. And see if the idle goes down. It seemed to work on both of my z's. And what year is yours? You might possible have a idle screw that you can adjust. It should be somewhere near the throttle cable. Because I think after '80 they were factory adjusted. And you can't change it. Hope this helps.

 

you can change it mines 81 and it has the idle adjust

but it seems it kicks up the revvs when he goes into gear,....

 

Thanks for the advice guys; I guess I'm gonna try the screw first. Where might said screw be located?

 

yellow circle...

 

Also, you might want to check the throttle return spring to make sure it's returning the throttle bar back all the way...

 

Thanks guys, I'll check it out once I can afford to put gas in it agian. I'm in between jobs lately because I'm going back to school in a moth or so and my hours are going to be weird; the Z ate up like $30 in gas last week, plus the few hundred I spent for my '83 Z..... they're going to have to be happy sitting for a few weeks, atleast until the first warm day.

 

Glad we could help a fellow ZX lover, and owner. Good luck

 

I checked but could not find that (what was pictued) on my car. There was like a stop screw around where the throttle return spring connects and I think it would fix the problem, but it screws in from the bottom and I can't really turn it. Am I crazy or does this exist on a '79? I really need to fix it soon because I totaled my other car in the snow today, so the Z is currently my only ride.

 

i dont know, i think bleach does...did in early zx's the idle screw was mounted IN the AFM????

 

It can't really be to much different from my cars. It has like a hole and on the bottom is a standard or slotted screw. Turn it one way and then the next. It should be the same. It is the same engine, and most of the parts. Do you have a repair or service manual? I have my workshop manual out right now. And the idle adjustment screw should be on top of the throttle chamber. Clockwise for slower, and counterclockwise for faster. According to my book. Hope this helps!

 

Yeah, it've got a repair manual, I'll look at it tomorrow, dosen't matter much now since the Z is under a ton of snow.

Oh, here's a pic of my '83 parts car. It really dosen't have as much damage as it looks, the radiator didn't even touch the engine.