# 89 d21 4x4 z24 rough idle



## pittmanjustin (Apr 11, 2011)

i have a 89 nissan ext cab z24 tbi has 140k it idles real rough and sometimes flods has new wires plugs coils cap and rotor wat else could cause this it runs fine drivin just wont idle when i turn ac on idleing it almost dies


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## zanegrey (Dec 5, 2005)

READ THE CODES...


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## pittmanjustin (Apr 11, 2011)

i cant read the codes because he check engine light doesnt come on when turn the key on


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## zanegrey (Dec 5, 2005)

THE 89 TRUCK DOES NOT HAVE A CE LIGHT...

READ THE STCKY AND READ THE CODES...


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## pittmanjustin (Apr 11, 2011)

do you have a link to where i can find out how to read the codes


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## zanegrey (Dec 5, 2005)

it is at the top of the hb thread page...


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## SPEEDO (Jun 9, 2003)

thanks! I needed that this morning!


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## pittmanjustin (Apr 11, 2011)

i checked the codes no codes in mode 3 just 55


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## smj999smj (Jan 1, 2006)

Possible issues: bad O2 sensor, excessive fuel pressure (bad regulator), low compression, vacuum leaks (leaking intake manifold gaslets and throttle body gaskets are not uncommon), dirty "hot wire" on the hot wire modulator (aka mass air sensor)...to name a few.


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## pittmanjustin (Apr 11, 2011)

wouldn a o2 sensor throw a code the truck has a header on it i dont know if its factory or not and i did find a few vacuum lines capped off the motor has been replaced before i got itdoes any one have a vacuum diagram for it thanks for the replies


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## smj999smj (Jan 1, 2006)

If the O2 sensor circuit was open or shorted, it would likely throw a code, but if the sensor had a rich or lean shift, it might not throw a code. Keep in mind the ol' 5 mode ECM's were not nearly as sensitive or sophisticated as modern OBDII ECM's.


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## smj999smj (Jan 1, 2006)

If you PM me with your e-mail address, I can send you a wiring diagram. Make sure you include "89 d21 4x4 z24 vacuum diagram" along with the trans type and if it's Federal or California emissions certification (should be on a sticker on the underside of the hood).


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## pittmanjustin (Apr 11, 2011)

i think i might have found the problem truck has a header on no cats just a glass pack i cant find a 02 sensor on it and the aiv is gone


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## pittmanjustin (Apr 11, 2011)

it started flooding real bad in town today i went home read codes and replaced the temp sensor runs good now still little miss at idle


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