I have read for hours on end on this forum and I still cant get my EEC to enter self test mode. I have tried using a analog multimeter,test light even watched my check engine light. Yes my 88 Hatchback has a CE light that actually lights up and no its not a Cali. car. But it does me no good only time i see it is while i am starting my car. Does anyone know of any certain reason why the EEC will not enter any form of test mode (chip,blown fuse/fusable link ect...). I have tried for a while now with no luck. If anyone else has had the same issue let me know please. My car would start idle rough for 3-5 sec and then die. After letting it sit over night it started but ran very rough. After cleaning MAF IAC and tracking down the vaccum leaks it seems to run much better. However it back fires when down shifting or decell. only in lower RPM usually under 2500rpm. Also a knock which I have yet pin point mostly when I down shift or low rpm decell. but will do some times when i rev the motor. I would really like to get to the bottom of this EEC problem so I can have a better idea of what is wrong with the motor. Any help would be greatly appreciated. And the sooner the better. THANKS for your Help.
Cant Get Codes/Car backfiring&knocking HELP!!!!!
- Thread starter AZNEAL311
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Fix the can't dump the codes problem and your other problems may go
away as a result. The can't dump the codes problem is usually a wiring
problem that affects the signal ground for the MAP/BARO, ECT ,ACT,
TPS & EGR sensors. The same wire that acts as signal ground is the
return path for the test mode circuit.
When the computer won't go into diagnostic mode, there are usually
several other problems hiding that reduce performance considerably.
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 OK, 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. You should see less than 1.5 ohms. More than that means a
break in the wiring .
Measure the resistance between the black/white wire on the computer test connector
and pin 46 on the computer wiring connector. You should see less than 1.5 ohms.
More than that means a break in the wiring .
Next measure the resistance between pin 46 on the computer and pins 40 & 60.
They should be less than 1.5 ohms. If it is more than 1.5 ohms, then the signal
ground inside the computer has failed. Unless you are an experienced electronic
repair technician, this means the computer needs to be replaced..
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.
away as a result. The can't dump the codes problem is usually a wiring
problem that affects the signal ground for the MAP/BARO, ECT ,ACT,
TPS & EGR sensors. The same wire that acts as signal ground is the
return path for the test mode circuit.
When the computer won't go into diagnostic mode, there are usually
several other problems hiding that reduce performance considerably.
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 OK, 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. You should see less than 1.5 ohms. More than that means a
break in the wiring .
Measure the resistance between the black/white wire on the computer test connector
and pin 46 on the computer wiring connector. You should see less than 1.5 ohms.
More than that means a break in the wiring .
Next measure the resistance between pin 46 on the computer and pins 40 & 60.
They should be less than 1.5 ohms. If it is more than 1.5 ohms, then the signal
ground inside the computer has failed. Unless you are an experienced electronic
repair technician, this means the computer needs to be replaced..
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.
Thanks jrichker. You seem to be the go to guy on here. I have some work cut out for me. Lucky me i already have my computer out(I was checking the MAF connections). The link you gave me to all the different digrams and misc. info is a gold mine. Ill be reading over that sight for a while. Thanks again I will let you know when I get it figured out or when I dont for that matter lol. I now have a place to start.
