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

Gas pig!!

  • Thread starter Thread starter MisterCMK
  • Start date Start date Apr 13, 2005

MisterCMK

20+ Year Stangneter
Oct 2, 2004
201
0
17
Fargo, ND
Apr 13, 2005
#1
  • Apr 13, 2005
  • #1
Hey guys, I've got a question for ya. I have been getting an average of 11mpg in the city ever since I bought the car back in october. Since then, I have added a CAI, MAC o/r H pipe, and new plugs, wires, and dizzy cap, and replaced the 02 sensors. She should be running like a top here. However, the mileage it is getting sucks. I have 2.73 and a 5spd. I get bad mileage no matter how I drive the car. It does run rich, as I can smell it when I come to a stop, or start the car in the morning. I am thinkin its the fuel pressure regulator. Whattdya think? Any ideas on anything else?
 

illwood

Member
Apr 3, 2004
636
1
19
Worcester, MA
Apr 13, 2005
#2
  • Apr 13, 2005
  • #2
How many miles are on the car? My '94 gets me about 18mpg city with a little "spirited driving". Are you sure that you have a 2.73 rear? I was pretty sure that '94 GTs got 3.08 rears.

I'd start checking for leaks on my injectors and fuel rails if I were you (and maybe the rest of the fuel system). That would help explain both the smell and bad milage.
 
4

4montecarlo

New Member
Feb 26, 2004
16
0
0
Apr 13, 2005
#3
  • Apr 13, 2005
  • #3
i would also replace the coolant temp sensor, i think its only about 20 bucks,
matt
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Apr 13, 2005
#4
  • Apr 13, 2005
  • #4
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $33.
 

MisterCMK

20+ Year Stangneter
Oct 2, 2004
201
0
17
Fargo, ND
Apr 13, 2005
#5
  • Apr 13, 2005
  • #5
She has 131k on it, and the 94 did come with 2.73. As for the smell, it smells like a car running rich, not like raw gasoline.

jr - will it still pull any codes if there is no CEL?
 

jackchan

New Member
Oct 17, 2004
507
0
0
Mobile Alabama
Apr 13, 2005
#6
  • Apr 13, 2005
  • #6
I'd check the themostat to make sure its getting hot enough! If someone replaceded it with a 170 degree or below it could be going in to choke loop and flooding! ............may not be your problem, but if I had to guess that would be my first guess! my car only gets 18-19 mpg on the hwy and I plan on changing mine out tonight for the same reason! I'll keep ya posted as to how it does...........
good luck
Jack
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Apr 13, 2005
#7
  • Apr 13, 2005
  • #7
codes can be stored w/o triggering the CEL.

the SN guys bend over backwards, forwards and jump through rings of fire to run rich (the factory tune is lean - ping city) so i doubt you are truly running rich. remember, the 94+ puters will adapt to stoich at all times (WOT included). it is hard to run rich, even if you want to. often when sensors get out of calibration, they tend to run lean. cleaning the MAF, ECT, ACT, et al sensors can help. not your case though.

the lack of cats is probably making a little bit of a stink that you are not used to.

SN's have the same 8.8 that foxes do - same ratios were offered (2.72, 3.08 and 3.27 as an option for autos).
 

MisterCMK

20+ Year Stangneter
Oct 2, 2004
201
0
17
Fargo, ND
Apr 13, 2005
#8
  • Apr 13, 2005
  • #8
I just put on a fuel pressure gauge, and she has about 28psi at idle, and when you give it a good strong rev, it will shoot to 34 or 35psi. I don't know what they are supposed to be, or if that is my problem. Thanks again guys
 

MisterCMK

20+ Year Stangneter
Oct 2, 2004
201
0
17
Fargo, ND
Apr 13, 2005
#9
  • Apr 13, 2005
  • #9
scratch that, it idles at about 24, and with a good rev, it will spike up to 30 or 31.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Apr 13, 2005
#10
  • Apr 13, 2005
  • #10
pull and cap the vac line to the reg - see what it reads. foxes are ~32 at idle with the line attached (i think down to 30 is acceptable) and around 38-40 with the line capped (which simulates WOT).

sounds like your pressure is low, but i would investigate further (as well as checking if it is the reg or pump). good luck.
 

MisterCMK

20+ Year Stangneter
Oct 2, 2004
201
0
17
Fargo, ND
Apr 14, 2005
#11
  • Apr 14, 2005
  • #11
When I have low fuel pressure, would that cause a rich condition, or would it cause the car to run lean? Thanks
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Apr 14, 2005
#12
  • Apr 14, 2005
  • #12
lean
 

MisterCMK

20+ Year Stangneter
Oct 2, 2004
201
0
17
Fargo, ND
Apr 14, 2005
#13
  • Apr 14, 2005
  • #13
Well, I checked the fuel pressure after she was warmed up with the vacuum line off the FPR. I got 19 psi. Do you think my fuel pressure regulator is going out on me?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Apr 14, 2005
#14
  • Apr 14, 2005
  • #14
one can carefully crimp the return line to see if it is the pump going bad or the reg returning too much fuel to the tank. i think it is more likely that the pump is on the outs, but checking will tell the story.

good luck.
 
You must log in or register to reply here.

Similar threads

Engine Fuel not pumping
  • Creomod
  • Apr 13, 2026
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
43
Views
704
Fox 5.0 Mustang Tech May 3, 2026
Shakerhood
S
Fuel ‘88 GT Runs Rich Cold — Fixes Itself When I Unplug Sensors (ECT, MAF, O2, etc.)
  • Sufarry
  • Nov 6, 2025
  • Fox 5.0 Mustang Tech
Replies
12
Views
733
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
2
Running very very rich
  • 2esoteric
  • Oct 31, 2025
  • Fox 5.0 Mustang Tech
Replies
4
Views
310
Fox 5.0 Mustang Tech Oct 31, 2025
Noobz347
8
Electrical Crank-no start ... no spark ... no injector pulse, was it something I did? (redux)
  • 85gtCOBRA
  • Oct 28, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
497
Fox 5.0 Mustang Tech Oct 29, 2025
85gtCOBRA
8
D
Engine 85 GT Backfires through Carb
  • DienstXIV
  • Oct 3, 2025
  • Fox 5.0 Mustang Tech
Replies
19
Views
585
Fox 5.0 Mustang Tech Oct 7, 2025
85GTStangGuy
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?