• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

my foxbody wont pass emisions any suggestions

  • Thread starter Thread starter wht92fox
  • Start date Start date Nov 29, 2005
W

wht92fox

New Member
Nov 21, 2005
2
0
0
Nov 29, 2005
#1
  • Nov 29, 2005
  • #1
I got a 92 5.0 and i took it for emissions and the hydrocarbons were twice the limit. It has cats but the egr is disconected and the air pump is no longer there. does anyone have any suggestions.
 

onefstsnake

New Member
Nov 25, 2005
792
1
0
Northern VA
Nov 29, 2005
#2
  • Nov 29, 2005
  • #2
I started a thread about this. Search!

Hydrocarbons...Make sure the car is hot before you get it tested.

My HC's were more than twice the limit, just warming the car up and they dissapeared...

Make sure your timing is set right as well. Stock is 10* I think.
 
P

PRO50SC

New Member
Dec 28, 2003
1,012
1
0
Olney, Maryland
Nov 29, 2005
#3
  • Nov 29, 2005
  • #3
Yeah, hook that stuff back up. I just went through, all my emissions stuff is on and passed by a long shot. Bigger injectors, blower, higher f/p, intake, t/b, mass air. All aftermarket. I couldn't believe it. I tried to go through once before with no cats and before the mods, wouldn't pass!!

Md is a tough state too.
 

vristang

15 Year Member
Mar 31, 2005
4,933
101
124
Seattle
Nov 29, 2005
#4
  • Nov 29, 2005
  • #4
wht92fox said:
I got a 92 5.0 and i took it for emissions and the hydrocarbons were twice the limit. It has cats but the egr is disconected and the air pump is no longer there. does anyone have any suggestions.
Click to expand...

Welcome to Stangnet!

Pull the codes from the computer. You may just have bad O2s. Possibly the cats are aging, and losing effectiveness.
What is your coolant temp? If you are running a 180F (or even worse 160F) T-stat that will make things alot worse. Use a stock stat for emissions testing, and make sure the motor is good and hot when you test. Leave the motor running while you wait for your turn.
I just read today that 50-80% of a vehicles emissions output during Federal testing can be from cold start alone.

The egr should not affect HC too much. I am suprised that you passed the NOx requirement without egr though. Does your state have NOx testing? I've heard some don't.
The air pump may help, but I can't say for sure.

Some fuel additives may help. "Gauranteed to Pass" has been mentioned here before, but I have never tried it.

:Word:
 

Maryland Stang

Active Member
Aug 21, 2002
1,656
30
39
Greenville, NC
Nov 30, 2005
#5
  • Nov 30, 2005
  • #5
As posted previously you need to check for codes and get that emissions equipment back in working order especially that air pump. My car passes MD emissions with a non functioning EGR but I'm also using a set of very low mileage factory cats and 10 degree base timing to do it. All of the rest of my emissions equipment is installed and functioning.
 
W

wht92fox

New Member
Nov 21, 2005
2
0
0
Nov 30, 2005
#6
  • Nov 30, 2005
  • #6
The car has new hi flow cats and new O2 sensors, but ill check the timeing and see what its set at. But as for the EGR and the air pump, I bought the car without them on. Do you think that new plugs and wires will help.
 

Look Its Aaron

Your car looks like it came straight from Mexico.
Founding Member
Nov 18, 2001
2,634
0
48
Fontana, Cali
Nov 30, 2005
#7
  • Nov 30, 2005
  • #7
put about 2 ounces of acetone per 10 gallons of gasoline, and that should reduce HC a lot.
 

RacEoHolic330

I like to dress like a pretty girl
15 Year Member
Mar 4, 2003
4,014
1,698
203
Allentown, PA
Nov 30, 2005
#8
  • Nov 30, 2005
  • #8
Look Its Aaron said:
put about 2 ounces of acetone per 10 gallons of gasoline, and that should reduce HC a lot.
Click to expand...

The optimum ratio is 3 oz/10 gal. BTW aaron, i'm consistantly getting 2 mpg better with my daily driver. I like this stuff.
 

DTT92LX

New Member
Oct 28, 2003
185
1
0
Downingtown, PA
Nov 30, 2005
#9
  • Nov 30, 2005
  • #9
The cats may not be functioning to their potential without the smog pump. The pump puts air to the cats (as well as the heads) to help reduce emissions. May have an issue there.
 

Look Its Aaron

Your car looks like it came straight from Mexico.
Founding Member
Nov 18, 2001
2,634
0
48
Fontana, Cali
Nov 30, 2005
#10
  • Nov 30, 2005
  • #10
RacEoHolic330 said:
The optimum ratio is 3 oz/10 gal. BTW aaron, i'm consistantly getting 2 mpg better with my daily driver. I like this stuff.
Click to expand...

Great! I am glad its working!!!


Try and see how much you have saved. Price of acetone vs mileage.
 

18mustangs

New Member
Jun 8, 2005
533
1
0
Virginia Beach, VA
Dec 2, 2005
#11
  • Dec 2, 2005
  • #11
DTT92LX said:
The cats may not be functioning to their potential without the smog pump. The pump puts air to the cats (as well as the heads) to help reduce emissions. May have an issue there.
Click to expand...

You got it. The catalytic converters need a catalyst to fully break down the unburned hydrocarbons, and this catalyst is the air from the smog pump. If he hooks the smog pump up to the cats he has a much better chance of passing.
Tim
 
You must log in or register to reply here.

Similar threads

2
Running very very rich
  • 2esoteric
  • Oct 31, 2025
  • Fox 5.0 Mustang Tech
Replies
4
Views
353
Fox 5.0 Mustang Tech Oct 31, 2025
Noobz347
J
Emission problems
  • jls.zmmr
  • Feb 5, 2026
  • 1994 - 1995 Specific Tech
Replies
2
Views
247
1994 - 1995 Specific Tech Feb 7, 2026
AeroCoupe
Resolved Three way cat converters..?
  • PonyGTrider
  • Nov 2, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
7
Views
270
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Nov 2, 2025
PonyGTrider
S
Preparation for Holley Terminator X install – Foxbody 306 (electrical fan, alternator, MSD Ignition, etc)
  • So_Flo
  • Mar 1, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
22
Views
2K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Mar 4, 2026
General karthief
S
Fox '87 GT can't get to stay running
  • spilly
  • Mar 29, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
27
Views
837
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 20, 2026
spilly
S
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?