# High idle issues with 87 z24 engine



## Ceyote220 (Mar 27, 2020)

Just bought 87 nissan XE w/ Z24 engine for a work truck. I cannot get idle to come down at start up. It revs and sustains about 4500rpm and won't come down. Done complete tune up. Any ideas?


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## jp2code (Jun 2, 2011)

Likely a vacuum leak. Do you know how to check for those?


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## Ceyote220 (Mar 27, 2020)

After further research it appears that parts are missing. Some sort of cam arm that connects throttle to fast idle cam too control idle at start up?


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## jp2code (Jun 2, 2011)

My 94 doesn't have a throttle body, so I can't help


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## Ceyote220 (Mar 27, 2020)

Thanks for your time


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## rogoman (Dec 16, 2004)

Ceyote220 said:


> After further research it appears that parts are missing. Some sort of cam arm that connects throttle to fast idle cam too control idle at start up?


Here's a picture from the 1988 FSM showing the fast idle adjustment. Maybe yours is the same.


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## smj999smj (Jan 1, 2006)

One thing to look at is the wax element (sometimes called the "hot wax"). If you look at the picture in post #3, in the upper right hand corner, you can see a plunger coming out of a round cylinder. It's essentially a cartridge with a plunger and filled with wax that slides into a chamber in the throttle body. The chamber in the throttle body has coolant running through it. When the wax element is cold, the plunger is extended, which pushes against a lever and causes the idle to be high. As the engine runs, the coolant gets hot, flows through the chamber in the throttle body, heats the wax element, causing the plunger to retract, which lowers the cold start fast idle. A couple of things can happen to these. One is that a clog could occur, restricting or blocking the flow of coolant through the throttle body, so the plunger stays extended. The other thing is that the wax element can go bad and the plunger will no longer retract. The wax element is usually a dealer item and probably still available. Start the engine and run it at 2000 RPM for 2-minutes and you should be able to see the plunger retract back into the hot wax. If not, make sure the coolant flow is not blocked going through the throttle body and if that's okay, replace the wax element. Now I'm not saying this is your specific problem, but something to keep in mind when trying to diagnose it as it often goes overlooked. 
Of course, another problem that occurs on these engines (and has nothing to do with the wax element) is when people mess with the idle set screws, which are set at the factory and should be left alone most of the time.


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## Ceyote220 (Mar 27, 2020)

Thank you for taking time to respond. In a final ditch effort I started it and stomped the gas pedal a couple times and everything seemed to reset it self. Made a few idle adjustments and now pures like a kitten.


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