How do I tune a fairly stock 5.0?

1987Rock

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May 2, 2007

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Dec 26, 2007

#1

• Dec 26, 2007

• #1

Ok, I just bought my first mustang. It's a 1994 5.0 5-speed. It's stock other than long tube headers, cold air kit, smog pump delete and the E-cam. I don't have any professional tuning equipment, so is there any way to tune it in my garage? I heard somewhere that you have to have a pro scanner to tune it through the computer. I don't want to do that if I can help it. It runs good, but it's way too rich and I need it to pass emissions.

 

Black95GTS

Active Member

Jan 8, 2004

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Marlborough, MA

Dec 27, 2007

#2

• Dec 27, 2007

• #2

All it has is an e-cam? Someone tore the entire engine down just to swap in an e-cam and put the rest of the stock crap back on?

The e-cam should be emissions friendly as it carries a CARB number. Something is not right if the car is running extremely rich with just the 4 mods you listed.

You will fail visual inspection based on the smog pump delete and the long tube headers. Long tube headers are "race only" parts.

Adam

 

1987Rock

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May 2, 2007

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Dec 27, 2007

#3

• Dec 27, 2007

• #3

Yeah, I know it should run fine, but something's wrong. The 3rd owner of the car took it apart to put the cam and some GT40 heads on it, but later put the stock heads back on.
It may just be that I need to back the timing off. The guy before me advanced it enough to need to run midgrade fuel, so it might be way to advanced.
In georgia, they don't inspect the cars, they just test them for emissions, so longtubes and no smog is no big deal.
Could the MAF be bad? I've heard that those go out a lot on Fords.

 

final5-0

Mustang Master

Apr 6, 2003

6,817

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79

DFW Texas

Dec 27, 2007

#4

• Dec 27, 2007

• #4

The timing should not make it run too fat

What evidence do you have it is too fat

If someone put an afpr on there, it may be cranked up too much

I guessing ... if you got no air pump ... you got no cats

I'd think you'd have a hard time passing with no cats

Grady

 

1987Rock

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May 2, 2007

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Dec 27, 2007

#5

• Dec 27, 2007

• #5

Well, I know it's too fat because of the smell and the tailpipes have a thick crust all in them.

I do have cats, so even with theout the air pump, it should pass.

My dad brought a scan tool home from work today and it turns out the O2 sensors are shot, so the engine senses a lean condition and compensates, so it ends up being entirely too rich. So 2 O2 sensors should fix it. I hope

Also, my car's an October 93 production and I've only been able to find 2 O2 sensors, but the parts store says there should be 4. Anyone know what the deal is?

 

urban96

bubb rubb says:"woo woooooo"

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Sep 24, 2002

3,464

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Syracuse, NY

Dec 31, 2007

#6

• Dec 31, 2007

• #6

http://www.automedicsupply.com/

our cars only have 2 sensors, you want the "pre cat" ones

 

1987Rock

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May 2, 2007

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Jan 6, 2008

#7

• Jan 6, 2008

• #7

Ok, more drama. I've got all the leaks fixed and I've run the car through a few diagnostic tests. I'm gonna put new O2 sensors on it, but when I tested it for emissions, it shot a 2000 on a 220 scale for hydrocarbons

That was on idle. It passed everything else at idle and was great off idle. It doesn't have a smog pump on it, but shouldn't it be better than that?

Could it need a custom chip for it?

The only thing me and my dad can figure is that the cats aren't staying warm enough to cook the HCs or that the cats are too far downstream. They are about 6 inches downstream of the longtubes.

Any ideas?

 

1987Rock

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May 2, 2007

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Jan 6, 2008

#8

• Jan 6, 2008

• #8

Would one of those Tweecer things do the job?
This is very frustrating. I know those bolt ons wouldn't cause this much trouble, but I'm wondering about the smog pump?

 

Zero_chance

Founding Member

May 29, 2001

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Maricopa, AZ

Jan 10, 2008

#9

• Jan 10, 2008

• #9

If the o2s are indeed bad until you fix them, the PCM will see the lean condition and compensate. Dont forget too the smog pump puts fresh air into the cats which helps catalyze the hydrocarbons, etc. So Im sure thats not helping. You should diagnose the 02 codes, fix the problem then reset the KAM. Because the PCM has adapted the fuel strategies to run witht the lean condition.

 

1987Rock

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May 2, 2007

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Jan 13, 2008

#10

• Jan 13, 2008

• #10

Well, it barely passed emissions, but I think I'm gonna build a 331 stroker this summer, so I'm not gonna mess with it anymore till then cuz it runs great. Thanks for all the help.