Code 94/44 Update

[fost9508]

Well I have been battleing trying to clear these 2 codes. Jrichker posted a way to check the air system, which I did and here is what I found below, I don't know what to make of it.

With the engine running I first checked the smog pump and valves, all okay. Next I went to work on the vacuum solenoid valves. First I disconnected the connector and checked voltage at the connector, 14V, ok. Plugged the connect back in and probed the wires, 14V, ok. Then I disconnected the vacum line from the first valve and noticed that the vacuum was alway on, even when I grounded the connection to the hood ground. I am thinking the circuit must be grounded out somewhere in the mess of wire Need some help here.

Next I moved to the other vacuum solenoid vavle. Checked the connector for voltage, 13.5V, ok. Plugged the connector back in and probed the wires. I must have not been able to probe the green wire, even though I pushed the pin all the way through the wire, because I couldn't read a voltage, so I ground the circuit to the hood ground and got a voltage, no change in vacuum though.

Now I am not sure if I just went about this thing all wrong, but I need some help.

Thanks a lot in advance.

fost9508

 

[86T-Top]

You have to remember that there is always a 12V source at these solenoids, however not a constant ground. When the computer decides it is time to open the solenoid and let the vacuum pass it supplies a ground to the solenoids.

For the first solenoid, unhook the connector and hook up a voltmeter to it. With the engine running you shouldn't see 12V, until you rev it up. If you see a constant 12V at idle there is a problem. Either the ground wire has shorted or the computer went bad, most likely the first. To tell if it is the wire or the comp probe either pin 38 or 32 on the back of the harness from the comp; use this diagram to decide which one http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

And prob the 12V source at the solenoid. If you have 12V all the time bad comp, if not bad ground wire.

Do the same thing with the 2nd solenoid. If you do not have a constant 12V on your voltmeter you are golden. NExt hook a vacuum gauge to the solenoid and see if you get any vacuum when you rev the engine. If you don't you need to replace the solenoid, if there is a vacuum being supplied to the solenoid. Note that when the solenoid opens you can hear it click.

Hope this helps

Mario

If you are still getting a

 

[fost9508]

Mario,

I appologize, but I am not to familiar with the computer. I know it is located on the passanger side behind an interior panel. I am not sure if I need to remove anything else and the best way to probe the wire from the computer without removing everything...have any suggesions????

Thanks

Jared

 

[86T-Top]

You need to remove the Passenger side kick panel to gain access to the computer. Once there remove the harness from the computer, you will need a 1/4 drive socket with I think a 10mm socket to remove the bolt in the middle of the connector. Once you have the connector off probe which ever wire you need with a voltmeter. Then send the other side of the voltmeter to a good ground on the car and do a continuity test. You should get an open circuit which is noted as 1. If you get 0 or any other number other than 1, there is a short in that wire to ground.

There is another way to do this which will be easier for you. You still need to remove the harness from the comp. Once that is done put the pos lead from your voltmeter to the pos terminal of your battery and the neg lead of the voltmeter to the ground wire on the connector for the solenoid and check to see if you get 12V. If you do get 12V or any voltage for that matter, your ground wire has shorted.

This btw is how you would check out the wiring for the EGR solenoid also.

If you determined that the ground wire has not shorted, than unfortunately there is a problem with your computer.

Mario

 

[fost9508]

Mario,

Thanks for the help again. I have another question, and I am not very electrical savvy, so bare with me. Now if I had a loose connections or broken wire would I also show an open circuit? Could I have either a short or an open circuit and still see the same problems?

Thanks

 

[86T-Top]

If you had a loose connection or broken wire, they would both show up as an open circuit during a continuity check, if and only if the loose connection was "loose" at the time.

What you have to remember is that the comp provides a constant 12V to each of the solenoids (the 2 smogs and the EVR (the one for the EGR)). So what you need to check is if the computer is providing a ground at the other pin on these connectors.

What you need to do.

The 1st solenoid sounds like there is a constant ground being supplied. You need to check that line to see if it has shorted out to the car. Short= the wire is making contact with the metal on the car, due to insulation wearing out. If the wire was just broken this would not be a problem, because there would not be a constant ground. To check for a short do this :
There is another way to do this which will be easier for you. You still need to remove the harness from the comp. Once that is done put the pos lead from your voltmeter to the pos terminal of your battery and the neg lead of the voltmeter to the ground wire on the connector for the solenoid and check to see if you get 12V. If you do get 12V or any voltage for that matter, your ground wire has shorted.

If you determine that there is not a short than everything is fine with the 1st solenoid, b/c you have already determined that vacuum is passing the solenoid and we just check to see if the ground wire was shorted. You then need to move on to the 2nd Solenoid.

All the same principals and tests work with the second smog solenoid.

Mario

 

[jrichker]

Excellent advice 86 T-TOP

some more thought along the same path...


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

And http://fordfuelinjection.com/index.php?p=6 for a computer connector pinout chart