This is topic foxbody codes 94/44 HELP!! in forum Tech Talk at Northern California Ford Owners .
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Posted by 83notcher (Member # 12608) on
:
Ive got a bone stock 87 mustang 5.0 speed density car
ive cleaned everything to do with the smog equipment including the crossover pipe behind the cylinder heads. still getting the codes. KOEO ive got code 11 which checks out good. KOER codes is 94/44 only no other codes
When I purchased the car it smogged no problem. now its high on HC hydro carbons but passed with flying colors on NOX and CO
The car backfires pretty bad when decelerating. It has great power throughout the RPM range. Its had a recent tune up including almost all sensors and O2 sensors
any advice would be awesome
Posted by 83notcher (Member # 12608) on
:
all vaccum lines and TAB and TAD sensors are good and connected in the right place
Posted by *Als50* (Member # 6003) on
:
...
[ 2015-08-13, 10:19 PM: Message edited by: *Als50* ]
Posted by rollininmy50 (Member # 9067) on
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when you checked the rear tube that connects the heads did you blow threw it? And also did you feel the back of the heads to see if it is not clogged, also if you do find that there is carbon build up you might as well take the upper intake off and see if the hole in the center is clogged as well , carbon build up. If all smog is correct and timing good it should pass fine.
Posted by 83notcher (Member # 12608) on
:
Cross over tube was clogged. I cleaned all the ports on the back of the heads and the crossover tube a while ago. Its still throwing codes. I haven't taken the upper intake off to clean the port because isn't the port in the middle for egr my egr works fine.
Posted by Blind (Member # 3052) on
:
Codes 44 & 94 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks.
Revised 28-Oct-2009 to correct code definitions and operation.
Code 44 RH side air not functioning.
Code 94 LH side air not functioning.
The computer uses the change in the O2 sensor readings to detect operation of the Thermactor control valves. When the dump valve opens, it reduces the O2 readings in the exhaust system. Then it closes the dump valve and the O2 readings increase. By toggling the dump valve (TAB), the computer tests for the 44/94 codes.
Failure mode is usually due to a clogged air crossover tube, where one or both sides of the tube clog with carbon. The air crossover tube mounts on the back of the cylinder heads and supplies air to each of the Thermactor air passages cast into the cylinder heads. When the heads do not get the proper air delivery, they set codes 44 & 94, depending on which passage is clogged. It is possible to get both 44 & 94, which would suggest that the air pump or control valves are not working correctly, or the crossover tube is full of carbon or missing.
Check to make sure that some one hasn't put a plug in the rear crossover tube mount on the cylinder head. The front ports are plugged, and occasionally someone will put the heads on and not notice the head is supposed to be installed with the crossover tube plug in the front.
Testing the system:
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 wheel well 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.
Typical resistance of the solenoid valves is in the range of 20-70 Ohms.
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
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