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

help!code 44 and 94 please help!

  • Thread starter Thread starter lazystang
  • Start date Start date Jun 18, 2007
L

lazystang

New Member
Jun 18, 2007
14
0
1
Jun 18, 2007
#1
  • Jun 18, 2007
  • #1
Hi,well it's a pretty complicated story about my car so i'll get to the point!
bought the car 89 mustang 5.0 no mods 2 months ago 110 000miles
ever since i got it it backfires and reaks of gas,the parts i just changed to narrow down the problem -fuel press reg,-egr valve,-o2 sensors,plugs,cap,rot,wires
bla,bla and didn't change a thing,got code 44 and 94 heard it's thermactor air systems not operating properly but i'm no mechanic and would apreciate any help out there PLEASE!!!
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Jun 18, 2007
#2
  • Jun 18, 2007
  • #2
Codes 44 & 94 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks. Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump the pump's output to the atmosphere or pass it to the next valve. The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes from one hose to the next.
The two electrical controlled vacuum valves mounted on the rear of the passenger side wheelwell turn the vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire. Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to the light green/black wire on the second solenoid and it should open and pass vacuum.

Remember that the computer does not source power for any actuator or relay, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.

The computer provides the ground to complete the circuit to power the solenoid valve that turns the vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel & the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin 32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Starting the engine with the computer jumpered to self test mode will cause all the actuators to toggle on and off. If after doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38 and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin 38 & Solenoid valve #1.

If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation. Power & ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

See http://forums.stangnet.com/attachment.php?attachmentid=50636&d=1180923382 for a very nice drawing of the Thermactor Air System (smog pump) plumbing

If you have a catalytic converter H pipe, you need to fix these codes. If you don't, then don't worry about them
 
L

lazystang

New Member
Jun 18, 2007
14
0
1
Jun 18, 2007
#3
  • Jun 18, 2007
  • #3
just to make sure i wouldn't do all that for nothing..if i take the cats off would it fix the problem?just curious!
 
L

lazystang

New Member
Jun 18, 2007
14
0
1
Jun 18, 2007
#4
  • Jun 18, 2007
  • #4
sweeet!that air system diagram is pretty useful..helped a whole lot already just understanding how it works thanks a bunch!
 

ShortThrow50

Member
Oct 22, 2006
923
2
16
Pa
Jun 18, 2007
#5
  • Jun 18, 2007
  • #5
lmao. I just asked this same question a couple weeks ago. I think i get those codes cause i deleted the smog pump
 
L

lazystang

New Member
Jun 18, 2007
14
0
1
Jun 18, 2007
#6
  • Jun 18, 2007
  • #6
but by fixing these codes,will the backfire in the exhaust stop?
it's getting annoying because everytime i go to the garage even they can't tell me what's wrong
 

ShortThrow50

Member
Oct 22, 2006
923
2
16
Pa
Jun 18, 2007
#7
  • Jun 18, 2007
  • #7
lazystang said:
but by fixing these codes,will the backfire in the exhaust stop?
it's getting annoying because everytime i go to the garage even they can't tell me what's wrong
Click to expand...

I just did trick flow h/c/i bro. I dont get any back fire. I got the codes after the first start up because I deleted the smog pump and run an O/R h pipe. I dont know what could be causing your back fire. You should start a new thread about your backfire and im sure some of the guys will tell you what the problem is.
 

93 LX

Founding Member
Jun 2, 2000
3,081
3
0
Norwalk, CA.
Jun 18, 2007
#8
  • Jun 18, 2007
  • #8
I get those codes too. I was unable to rid myself of them but the engine runs ok. It does run a bit rich but I think maybe its something to do with the speed density crap. I will be upgrading it to Mass Air later this year. I verified my solenoids are good and the wiring is good as well. I put a vacuum gauge on the TAD and TAB valves and they work as designed.

Who knows why this still generates errors but I just live with it.

Allen
 
You must log in or register to reply here.

Similar threads

J
Thanks for the information on codes 31,34,44 and 94!
  • JK86LX50
  • Mar 5, 2025
  • The Welcome Wagon
Replies
3
Views
295
The Welcome Wagon Aug 5, 2025
gkomo
Engine Throwing codes 94, 33, 34, 44, and sporadic engine shutoff.
  • Ryu
  • Oct 9, 2024
  • Fox 5.0 Mustang Tech
Replies
11
Views
1K
Fox 5.0 Mustang Tech Oct 16, 2024
89ripper
Electrical Innovate PSB-1 is DOA? Am I an idiot? All plausable. Please Help
  • Dontknowchit
  • Apr 26, 2025
  • Fox 5.0 Mustang Tech
Replies
1
Views
478
Fox 5.0 Mustang Tech Apr 26, 2025
Dontknowchit
A
95 Gt intermittent backfire
  • A_A_Ron
  • May 26, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
0
Views
429
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 26, 2025
A_A_Ron
A
W
1987 mustang gt 5.0 flooding itself when it’s in gear
  • Willyc
  • Sep 1, 2022
  • Fox 5.0 Mustang Tech
Replies
10
Views
2K
Fox 5.0 Mustang Tech Sep 3, 2022
Willyc
W
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?