2096920

My Car Won't Run

June 17th, 2005 04:05 PM

I need some help guys. I own a 96 Mercury Cougar with a 4.6L V8. The car is running very rough, i have changed the spark plugs and the wires and it's running even worse now. I noticed when I cahnged the plugs on the right side of the engine they were black. What could this mean? Any suggestions are welcomed.

2096925

Re: My Car Won't Run

June 17th, 2005 04:07 PM

Black and dry or black and wet?

Check engine light on?
Any cracks in vacuum tubing?
This engine have a dist or dist-less ignition?

2096933

Re: My Car Won't Run

June 17th, 2005 04:10 PM

It has coils and the plugs were black and dry.

2096970

Re: My Car Won't Run

June 17th, 2005 04:24 PM

My first guess would be carbon fouling (usually caused by an over-rich air-fuel mixture).

Tell us a little more about the engine. Does the intake manifold use a common plenum, or does each bank get it's own? One fuel rail per bank? TBI?
I'm taking stabs here, but you never know when you might stumble into the right answer...

2096982

Re: My Car Won't Run

June 17th, 2005 04:28 PM

I'm not quite sure what your asking. I work on the outside of cars not under the hood.

2096987

Re: My Car Won't Run

June 17th, 2005 04:32 PM

Fair 'nuff. TBH, I'm not all that well-versed with the finer points of modern engines

Where'd I lose you?

2096997

Re: My Car Won't Run

Shintsu

June 17th, 2005 04:36 PM

I know what the problem is...its a Ford

To be honest I'm not that much of a car person so I'll just sit here with a notepad and take notes from the wisers.

EDIT: If you love cars that don't run right then I see why you love Fords :lol:.

2097002

Re: My Car Won't Run

June 17th, 2005 04:38 PM

You lost me at the fuel plenum and rails. BTW I love my Ford

2097045

Re: My Car Won't Run

June 17th, 2005 04:55 PM

Old Ford Syndrome is a very real affliction Trust me; I've got a '77 Ranger with a 460.

Ok then: how does air enter the engine? On most vehicles, there's a single air intake somewhere that feeds into a chamber (the plenum) atop the engine. Typically, this part of the intake is more or less a common area to all cylinders, but not necessarily always. Since I don't know offhand how 4.6L Ford was designed, I thought I should make sure.
Fuel rails exist on port-injected engines. They're basically hollow pieces of metal that the injectors tap into, and all they do is feed fuel to the injectors. They look just like a metal tube running the length of each cylinder bank. Every port-injected system I know of is considered to be "dry", where fuel is added to the intake charge only as it enters the cylinder.
Throttle body injection (TBI) moves the injector(s) to the throttle body itself. This is considered a "wet" system, as the fuel is added to the engine as soon as air enters the engine (carbureted engines are also wet).

If you've got four clean plugs on one bank and four dirty plugs due to carbon deposits on the other (which sounds like that you describe), then the side with fouled plugs is receiving too much fuel. That's why I'm wondering how air and fuel induction is being handled with your engine.

2097091

Re: My Car Won't Run

June 17th, 2005 05:19 PM

Ok i think I understand now. There is only one intake and i don't believe there is any fuel rails.