1999 Mitsubishi Eclipse Idleing high

NAVYBOY

MEMBER
1999 MITSUBISHI ECLIPSE

Engine Performance problem
1999 Mitsubishi Eclipse 4 cyl Front Wheel Drive Manual

I just replced my head gasket. Now when I start it up it jump to 5000 rpm quickly then slowly rise higher. I got black smoke coming out the exhause which I think it getting to much air. I replaced all the gasket on my intake maniflold and mass airflow sensor and checked all my vacum lines. Could it be something else then getting to much air or anything else

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and throttle position sensor out of range