comp wont thro codes
- Thread starter bcd
- Start date
With the power off, measure the resistance between the computer
test ground (black/white wire) on the self test connector and battery
ground. You should see less than 1.5 ohms.
If that checks good, remove the passenger side kick panel and
disconnect the computer connector. There is a 10 MM bolt that holds
it in place. Measure the resistance between the STI computer self
test connector (red/white wire) and pin 48 on the computer main
connector.
Diagram courtesy of Tmoss & Stang&2birds
See the following website for some help from Tmoss (diagram
designer) & Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine
The following is a view from the computer side of the computer connector.
test ground (black/white wire) on the self test connector and battery
ground. You should see less than 1.5 ohms.
If that checks good, remove the passenger side kick panel and
disconnect the computer connector. There is a 10 MM bolt that holds
it in place. Measure the resistance between the STI computer self
test connector (red/white wire) and pin 48 on the computer main
connector.
Diagram courtesy of Tmoss & Stang&2birds
See the following website for some help from Tmoss (diagram
designer) & Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine
The following is a view from the computer side of the computer connector.
Black1987Stang
Active Member
Jrichker while I got ya, since my stang doesnt have a check engine light (87) what wire do i hook it up to looks like 17 on ur diagram? I saw an article on it somewhere and I cant find it. I think it calls for a bulb in the HELP section and to solder that wire to the circuit on the back of the cluster, and im assuming a ground too if there isnt one back there.
Copied from mustang88GT:87stangdiddle said:
I have not finished it yet but I put the bulb in and it works. There are wires that you can tap into and run to the self test connector. The reason I have not run the wires yet is because I am tripping 2 codes because I did not run wires for the secondary fuel pump or speed senor yet for the MAF conversion... but it should be real easy to do here is
Adding a "Check Engine" light
Another difference between the speed density and MAF cars is that MAF cars have a "Check Engine" light in the dash to alert you to possible serious problems and it makes reading out self test codes much easier. The MAF cars have the "Check Engine" light located in the light panel on the lower right of the instrument cluster. Speed density cars don't have this window, but there is a "Check Engine" position for a light in the tachometer face, though there is no bulb installed. The wire from the EEC to the bulb (via the flex connector) is also missing.
In the '88 harness (not sure of other years), there is a tan and a black/blue wire connecting up to the 'Check Engine' circuit on the instrument cluster flex circuit. For MAF models, the tan wire hooks to the EEC STO/MIL line and the black/blue is for the lamp test out when you start the car. I don't know what these are connected to in an '88, but the test out feature does not work, and the STO/MIL line at the EEC-IV and self test connector is yellow/black. The wires connected to the check engine lamp probably end at some open connector somewhere, but I couldn't track it down, so I cut the tan and black/blue wires off the flex connector and ran a new wire to the STO/MIL wire on the self test connector under the hood (you could also tap in by the EEC-IV, but it was easier for me to go through the firewall. You can get a bulb socket from the HELP! rack at the local parts store, put in a N194 bulb, and voila, you now have a working check engine light.
The wiring for the computer self test connector is the same for both years. Unless you miswired something, it should not cause problems. See http://www.stangnet.com/tech/maf/massairconversion.html for instructions to check your wiring.bcd said:
I have an 88 that was converted to MAF when I bought it. I have a check engine light near my tach. with a bulb in it. I see it light up when i am starting my car. However When I try to pull codes i get nothing. I have tried using the CE light,multimeter and test light and I havnt got any thing. Anyone have the same problem and have an idea on what I should do? I have yet to try a STAR reader waiting for my friend to find his for Ranger with a 302 he dropped in. Untill then any suggestions?
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