Mechanics

NISSAN TRUCK RPM PROBLEM

1985 Nissan Truck • 180,000 miles

When I got this truck (Nissan 720) it would not run. It has a z24 engine and Automatic transmission. I put in all new spark plugs, wires, distributor cap, rotor, new ignition coils and and a new carburetor. I have the truck running but it idles at around 1800 to 1900 rpm in park and around 1000 in drive. It is supposed to be set at 3 btc at 700 rpm, but if I set it that low it dies. It runs fine as long as you are driving it except you have to keep your foot one the accelerator when you come to a stop. When you put it park to turn it off it returns to that high idle and when you turn the key off it dies very rough. I am not sure what causes this or what to check next. Please advise. Thanks.
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Mmorris5m
November 14, 2012.



SOUNDS LIKE VACUUM LEAKS

MORE AIR SNEAKING IN--REQUIRES MORE GAS TO MIX WITH IT TO RUN. WHERE YOUR ADJUSTMENTS ARE NOW. ATTEMPTING TO GET 14.7: 1 AIR/FUEL MIX, WHEN WAY TOO MUCH AIR IS COMING IN

YOU PROBABLY CAN'T CUT DOWN ON THE GAS (IDLE SPEED AND MIXTURE SCREWS) TILL YOU GET THE EXTRA AIR TO STOP CREEPING IN

CHECK THEM HOSES AND CHECK THE INTAKE MANIFOLD SEAL TO THE BLOCK. AS WELL AS CARB ATTACHMENT. EVEN A LEAKY BRAKE BOOSTER. DON'T FORGET THE OLE PCV GOTTA BE IN THE SYSTEM----USE YOUR IMAGINATION

NO NEED IN EVEN ATTEMPTING TO TIME IT "RIGHT", 'TILL YOU GET THE IDLE SPEED DOWN TO 700 RPM. YOUR MECHANICAL OR CENTRIFUGAL ADVANCE WILL STILL BE "SLUNG OUT" ABOVE THAT RPM. YOUR READINGS WILL BE INCORRECT

LET ME KNOW WHEN YOU ARE READY TO TUNE---NEED TO BE CLOSE TO THE 700 RPM

YOU WILL NEED A DWELL/ TACH METER AND A TIMING LIGHT

THE MEDIC

Tiny
CJ MEDEVAC
Nov 14, 2012.