Hi All! I am a new member here, but I confess I have been lurking since I bought an 89 GT 5-speed convertible a year ago (wife says it's my "mid-life crisis car") There's some great tech advice on here! Hope someone can help with this issue.
The fuel pump runs constantly with the key on, instead of priming and shutting off until start-up. Finally decided to dig into it (along with all the other winter projects) and turned out the previous owner strapped the relay to ground (under the seat!). Reason being there's no ground coming from the A9S EEC to operate the relay. Wiring checks out ok from relay to pin 22 of EEC connector, also to test connector under hood. I get 100k ohms to ground from the test connection with key off, open circuit with key on. I have solid grounds on pins 40 and 60 of the EEC connector, and I don't see any leaky caps or cold solder joints on the EEC board. EEC power relay is good. Strapped a ground to the test connector to get running, and I get the following error codes: Key Off 21, 24, 34, 87, Engine Running 21, 34, 41, 91. I do NOT get a code 11.
Do I have a failed EEC? Is that what code 87 (Fuel pump circuit D2 ) indicates? Is the code 91 (Oxygen sensor problem, fuel pressure out of specified range or injectors out of balance) because the pump is running constantly? How likely is it that only the fuel pump ground circuit would fail?
The fuel pump runs constantly with the key on, instead of priming and shutting off until start-up. Finally decided to dig into it (along with all the other winter projects) and turned out the previous owner strapped the relay to ground (under the seat!). Reason being there's no ground coming from the A9S EEC to operate the relay. Wiring checks out ok from relay to pin 22 of EEC connector, also to test connector under hood. I get 100k ohms to ground from the test connection with key off, open circuit with key on. I have solid grounds on pins 40 and 60 of the EEC connector, and I don't see any leaky caps or cold solder joints on the EEC board. EEC power relay is good. Strapped a ground to the test connector to get running, and I get the following error codes: Key Off 21, 24, 34, 87, Engine Running 21, 34, 41, 91. I do NOT get a code 11.
Do I have a failed EEC? Is that what code 87 (Fuel pump circuit D2 ) indicates? Is the code 91 (Oxygen sensor problem, fuel pressure out of specified range or injectors out of balance) because the pump is running constantly? How likely is it that only the fuel pump ground circuit would fail?