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Low Idle (Near Stall)

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Low Idle (Near Stall)

Old 08-13-2018, 01:26 PM
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Exclamation Low Idle (Near Stall)

Hey everyone, when starting (cold) the 300zx (1987 Turbo) the idle is around 600 - 700, then it start dropping and sometimes even jumping at the 500 - 450 line like it's about to stall.

I'm curious why this is happening. Should I try and adjust the RPM? When in drive it sits at around 500.

Another thing, when starting the car it sometimes doesn't even start. I really gotta crank it for a good 2 seconds. I think it could be related. Thanks!
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Old 08-14-2018, 07:39 PM
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Yeah mine too ,as I remember. The idle motor froze likely you can clean the throttle plate, may help
the SAS screw is very hard to change that little that idle mtr was 180 in the 80s
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Old 08-14-2018, 08:28 PM
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Originally Posted by 86tcoupe View Post
Yeah mine too ,as I remember. The idle motor froze likely you can clean the throttle plate, may help
the SAS screw is very hard to change that little that idle mtr was 180 in the 80s
Should I try increasing the rpm's manually to start if I can't clean the throttle plate for now?

I'm thinking this may also have something to do with the vac lines since the car does have trouble starting up.
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Old 08-14-2018, 08:50 PM
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The IAC valve , next to the EGR valve may be stuck close. When it’s cold you should be able to blow through it. When it warms it closes. That was one of the issues with mine, 89T. I put a used one on but thinking about getting a new one.

I’d like to also clean my MAF as well. Mine starts right up idles good and about 30secs in does what yours does. I have to keep anout 1100rpm until it warms up or just get in and go.



Last edited by JSM; 08-14-2018 at 09:18 PM.
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Old 08-14-2018, 09:05 PM
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Originally Posted by JSM View Post
The IAC valve , next to the EGR valve may be stuck close. When its cold you should be able to blow through it. When it warms it closes. That was one of the issues with mine, 89T. I put a used one on but thinking about getting a new one.

Id like to also clean my MAF as well. Mine starts right up idles good and about 30secs in does what yours does. Butit takes 2min or so. I have to keep anout 1100rpm until it warms up or just get in and go.

Definitely will look into this further, do you suggest I simply increase the rpm idle manually for now?
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Old 08-15-2018, 01:25 PM
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No I would not increase the idle . I’m assuming once it warms your idle is fine? If you increase it, when it warms it will likely be even higher.

If it idles low low once warm too I would investigate your vacuum lines. Also check timing and general tune up first. Plugs, cap, wires, rotor etc.
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Old 08-18-2018, 07:15 PM
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Very easy to clean the throttle remove the intake tube open the throttle fully ( off)
spray carb spray on a blue p towel ,tooth brush and clean where the plate hits the housing
you can try jumping the idle air controller

my 86t has a idle swt. That needs to connect
​​​​​​​87 likely a tps , that needs to be set right too

Last edited by 86tcoupe; 08-18-2018 at 07:20 PM.
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