Running Rich Or ?

tx65coupe

Active Member

Nov 29, 1999

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Dec 21, 2009

#1

• Dec 21, 2009

• #1

My 65 has run a bit rich since we got it running again. I wasn't worried about that. Ever since the weather cooled down this fall, it seems that our Mustang has been running rich. I'm not sure if thats the case though. It doesn't smoke at all, but the exhaust smell is really strong behind the car when its running evan after it is warmed up and has been driven. Its strong enough that when driving for more that about 30 minutes causes our clothes smell like exhaust and fuel. After driving for a while and my eyes are irritated. I can not find any exhaust leaks. Also, it seems to be using quite a bit more fuel since the weather is cooler. Does anyone have any ideas what the issue is?

 

tx65coupe

Active Member

Nov 29, 1999

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Dec 21, 2009

#2

• Dec 21, 2009

• #2

Could this be my problem?

I read that the Edelbrock 650 AVS only needs 6 psi. Would I be better off with this fuel pump?

Edelbrock 1725 - Edelbrock Performer RPM Street Fuel Pumps - Overview - SummitRacing.com

I currently have this one that is rated for 8 psi.

Summit Racing SUM-250024-1 - Summit Racing® Mechanical Fuel Pumps - Overview - SummitRacing.com

 

gtss

Member

Apr 30, 2002

133

2

19

Airdrie,Alberta

Dec 21, 2009

#3

• Dec 21, 2009

• #3

I doubt its fuel pump related, if the pressure were too much it would be pushing the needle off its seat, which would result in flooding to a point of stalling, and possibly fuel coming out of the float bowl vents.

More than likely you have a choke issue, either incorrectly adjusted so its staying partially on even when warm,
or no power to the electric portion of the choke??
colder weather would definitely amplify the issue
gtss

 

tx65coupe

Active Member

Nov 29, 1999

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Dec 22, 2009

#4

• Dec 22, 2009

• #4

Good point. I'm going to take a look at the choke. I was thinking that might be the case also, but I thought it was working properly so didn't consider that before.

 

tx65coupe

Active Member

Nov 29, 1999

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Dec 24, 2009

#5

• Dec 24, 2009

• #5

I have checked the choke, and it is operating as it should. It is fully open after a few minutes. I checked it with the car off. It has an electric choke.

Everything is new, so I can only think of a couple things that could be causing it.

The first thing I thought of was the fuel pump, since Edelbrock recommends a 6 psi pump and it is an 8 psi Summit brand pump.

I was thinking it might be the 180 degree T stat. Should it be a 190 degree T stat?

The other thing I was thinking about was the plugs. I have Motorcraft copper spark plugs that are recommened for use with aluminum Edelbrock heads. AGSP32C I wonder if they are the wrong temperature. I doubt that is the problem.

The other thing I was thinking is that I have the vacuum advance connected to manifold vacuum and not the ported vacuum, because I have heard from many people including the guys that built my 302 that this setup will provide better throttle response and it will run better. I did see a note in the documentation that having it connected to ported vacuum will result in lower hydrocarbons though. Could this be the issue?

 

R

rebel65

Member

Feb 1, 2004

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SF Bay Area

Dec 24, 2009

#6

• Dec 24, 2009

• #6

do you have a cat? or is it more excessive than that?

 

tx65coupe

Active Member

Nov 29, 1999

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Dec 25, 2009

#7

• Dec 25, 2009

• #7

The car does not have cats. It never had them. I would say that the smell is excessive, because my clothes smell like exhaust. Also, You can't or don't want to stand behind the car with it running for very long or it will make your eyes water. It runs great though and there is not any smoke. So, I don't know if its rich or what.

 

woodsnake

15 Year Member

Jan 16, 2007

1,352

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Hicksville, NY

Dec 25, 2009

#8

• Dec 25, 2009

• #8

A performance cam will often cause a stinky exhaust too, with the bigger overlap at idle....

 

tx65coupe

Active Member

Nov 29, 1999

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Dec 25, 2009

#9

• Dec 25, 2009

• #9

I didn't think about that. I does have a performance cam. Would it cause it to be this bad? I think that maybe there is an exhaust leak somewhere.

 

woodsnake

15 Year Member

Jan 16, 2007

1,352

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69

Hicksville, NY

Dec 25, 2009

#10

• Dec 25, 2009

• #10

Unburned fuel at idle.....
Does it stink going down the road, or does it go like stink? I think it's more due to the cam, than an exhaust leak, but I can't smell it from here....

 

S-Car-Go

Member

Mar 25, 2003

332

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San Jose, CA

Dec 25, 2009

#11

• Dec 25, 2009

• #11

Some things to think about... Hows the fuel filter? Could crud have gotten into to the carb? How old is the carb? I'd pull the covers over the metering rods and make sure they move freely up/down into the jets. If one or both rods weren't pulling down, it would run rich. What is your vacuum at idle? You may need a lighter spring or a larger mettering rod. It wouldn't hurt to check the float level either. You've got the idle mixture screws set for highest vacuum/RPM, right?

 

tx65coupe

Active Member

Nov 29, 1999

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Dec 26, 2009

#12

• Dec 26, 2009

• #12

All the parts are new. Last winter/spring we replaced all the fuel lines and the gas tank. The fuel filter was new. The engine and carb were new then too. The car has close to 3k miles on it since the new drivetrain.

I don't think there is crud in the carb. I actually have 2 fuel filters. I have an Edelbrock filter by the carb and one of those transparent ones before the pump. It looks nearly like new.

I don't know what the vacuum is at idle, I will check that this weekend.

 

R

rebel65

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Feb 1, 2004

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SF Bay Area

Dec 26, 2009

#13

• Dec 26, 2009

• #13

i agree that smelling like gas after a drive is probably more extreme than not having cats. but i noticed a real difference in smell from having cats to no cats. my car always has a very slight smell of gas, but really can't stress the slight lol. but i hear from other people that i smell of gas when i get out of the car after a long drive, but i can't smell it unless i take the shirt off and smell it a few hours later and it smells like if you stepped in a little bit of gas at the station. but if you are smelling it as you drive.. that's way more than mine. just wanted to chime in on the whole cat thing.

 

CraigMBA

New Member

Mar 24, 2007

783

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Orange, CA

Dec 26, 2009

#14

• Dec 26, 2009

• #14

The smell you have is unburnt hydrocarbons, caused by the performance cam. New cars don't have that smell because catalytic converters get rid of the smell.

If you really think the car is too rich you can confirm it buy adding in one of those temporary Fuel Air ratio meters. The NKG piece is supposed to be the best one. If it isn't running too rich (I doubt it is) your options are to learn to live with it or to add cats.

I went through this about a decade ago before I figured it out. Good luck!

 

S-Car-Go

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Mar 25, 2003

332

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San Jose, CA

Dec 26, 2009

#15

• Dec 26, 2009

• #15

BTW, how big is this cam? What are the basic specs? What color are the plugs?