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

Running Rich, HELPPPP!!!

  • Thread starter Thread starter MikeH686
  • Start date Start date Oct 31, 2011

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Oct 31, 2011
#1
  • Oct 31, 2011
  • #1
Im having problems with my car running rich, when i bought it the guy said it was basically ready for boost, but i cant afford any of that right now so my question is, can i simply dial back the fuel pressure going to the injectors they arent that great deal in size only 24lb, i heard that stockers are only 19lb but the car has a 255lph walbro fuel pump, at least i think its walbro but anyways is it simply me just adjusting the fuel pressure back or is it much more then that, sorry i am a noob with this kind of stuff
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Oct 31, 2011
#2
  • Oct 31, 2011
  • #2
There is so little technical detail in your post that it is very difficult to give you any advice. It sounds like you have very little mechanical backgound and bought someone's unfinished project car because he talked a good sales pitch.

What year make and model is the car? You didn't say: you could be driving a Chevvy for all we know.
What cubic inch size engine?
What kind of computer - Speed Density or Mass Air? Does the computer have any kind of aftermarket or custom chip?
What cylinder heads, intake manifold, cam, cold air kit?
What MAF if Mass Air? Is the MAF calibrated for use with the injectors?
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Oct 31, 2011
#3
  • Oct 31, 2011
  • #3
Ok sorry I did not know I needed all that in such a simple post ... its a 302 with a .030 overbore forged 10:1 pistons with eagle h beam rods stock turned crankshaft custom ground lunati cam shaft 75 mm maf sensor going to a 70 mm throttle body
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Oct 31, 2011
#4
  • Oct 31, 2011
  • #4
Holly systemax upper and lower intake manifold full custom exhaust ... what happens is it runs rich at idle but seems to lean out when I drive it and get on it pretty good and sorry if I sound like a noon with this **** but this is my first project car in which I did not start from the beginning
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Oct 31, 2011
#5
  • Oct 31, 2011
  • #5
Oh probably don't matter but it has fluidyne aluminum radiator with dual electric fans
Rebuilt t5 trans
Aluminum driveshaft
4.10 gears
Mosley 31 spline shafts
Oh and its a 1991 ford hatch 5.0
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Nov 1, 2011
#6
  • Nov 1, 2011
  • #6
1.) MAF calibration must match injector size. Check to see that MAF sensor and MAF body are compatible. Check sticker or manufacturer's part number on MAF against their website to make sure it does. If it is a C&L MAF, check sample tube size and color.

2.) Check fuel pressure at idle
Check fuel pressure:
The local auto parts store may rent or loan a fuel pressure test gauge if you don't have one.
Disconnect vacuum line and check it for evidence of fuel present on the line. If you find fuel, the fuel pressure regulator has failed. Cap the vacuum line and stow it out of the way.
Connect fuel pressure test gauge to Schrader port located just behind the alternator.
Turn the ignition switch on & start the engine. Observe the pressure : you should see 37-41 PSI at idle.
Turn the ignition off, reconnect the vacuum line and disconnect the fuel pressure test gauge. Watch out for squirting gas when you do this.

3.) Dump the codes to find sensors that may be out of spec and causing problems. Codes may be present even if the check Engine Light isn't on.
Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way 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. You watch the flashing test lamp or Check Engine Light and count the flashes.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.





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.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.



The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some 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.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

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

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Nov 1, 2011
#7
  • Nov 1, 2011
  • #7
Fuel pressure gauge is that the same as any 1/4" fluid gauge?
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Nov 1, 2011
#8
  • Nov 1, 2011
  • #8
MikeH686 said:
Fuel pressure gauge is that the same as any 1/4" fluid gauge?
Click to expand...

As long as it says PSI it is the same.
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Nov 1, 2011
#9
  • Nov 1, 2011
  • #9
Ok well is the schrader port in the same spot when it comes to all lower intake manifolds? I have a holly systemax if that helps .. sorry if im sounding like a complete idiot but I didn't think that me buying someones started project would be this complicated ... oh and checked the maf and it says on the top of it calibrated to 24c but Idk what c means if you don't mind telling me I appreciate it
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Nov 1, 2011
#10
  • Nov 1, 2011
  • #10
There is only one schrader valve on the fuel system. It is the high pressure supply line that feeds the injectors. That is where you connect the fuel pressure test gauge.
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Nov 1, 2011
#11
  • Nov 1, 2011
  • #11
Oh ok I already have a gauge there .. I must've mis read it thinking it was behind the altenator but this one is on the fuel rail feeding the injectors ... took the vaccum line off and it jumped up to 40 psi ... put vac line back on and it dropped back to around 30-32psi
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,811
234
Dublin GA
Nov 1, 2011
#12
  • Nov 1, 2011
  • #12
MikeH686 said:
Oh ok I already have a gauge there .. I must've mis read it thinking it was behind the altenator but this one is on the fuel rail feeding the injectors ... took the vaccum line off and it jumped up to 40 psi ... put vac line back on and it dropped back to around 30-32psi
Click to expand...

Thats exactly what it should do.
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Nov 1, 2011
#13
  • Nov 1, 2011
  • #13
Hmm ok ... talked to a buddy he's saying since its cammed I will smell a little bit of un burnt gas but im gonna clean my maf and then check out my o2 sensors and see if that might change something
 

DuDNoTcH

Member
Dec 22, 2009
82
2
9
Dec 23, 2012
#14
  • Dec 23, 2012
  • #14
LMFAOOOOOO!!!!
 

MikeH686

Mine is only two inches though.
10 Year Member
Oct 11, 2011
2,843
1,753
184
Waldorf, MD
Dec 23, 2012
#15
  • Dec 23, 2012
  • #15
Wow seriously i found what the problem was anyways
 
You must log in or register to reply here.

Similar threads

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
740
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
J
Engine Running like crap :(
  • justadude07
  • Sep 27, 2025
  • Fox 5.0 Mustang Tech
Replies
8
Views
311
Fox 5.0 Mustang Tech Oct 19, 2025
DadLife0724
T
  • Locked
Digital Tuning A9l issue or something else
  • Tufgriz
  • Sep 11, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
267
Fox 5.0 Mustang Tech Sep 11, 2025
Noobz347
T
Fuel Looking for a little guidance
  • Tufgriz
  • Sep 11, 2025
  • Fox 5.0 Mustang Tech
Replies
9
Views
316
Fox 5.0 Mustang Tech Sep 12, 2025
Noobz347
J
Fuel Fuel Pressure Issue
  • justadude07
  • May 12, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
386
Fox 5.0 Mustang Tech May 12, 2025
justadude07
J
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?