Does the ECM control the factory gauge cluster? My 84 ss had an all mechanically controlled 350 swapped into it by the previous owner, and since then my lockup converter does not work even though still connected to the ecm. So last night I started testing the wires that run to the trans, and tried to toggle switch the torque converter(unsuccessfully). When they swapped motors they chopped every wire on the firewall on passenger side except for the transmission wires which I traced so I am sure of. Well to make a long story short.. After I played with those wires I lost my factory tach, volt gauge, temp gauge, and fuel gauge. So my guess is I fried the ECM, but I was unaware that all my factory gauges are controlled by it. I don't know what else it could be. No blown fuses. I also am running aftermarket oil pressure, temp, and volt gauge, so I can live without those, but I can't go without my fuel gauge. :?
ECM on 84 SS
- Thread starter je43278
- Start date
- Status
the ECM does not control the fuel gauge or any other guages for that matter ( other than the check engine ).
I also have an '84 SS and the 'puter is connected to a stand-alone harness which runs thru the lowest grommet in the firewall behind the PS front tire. If you remove the wheelwell you will see the wiring is connected to the 'puter in the car and all the sensors under the hood. The wiring just above it on the firewall is for the HVAC. The engine management wires run thru the bulkhead on the DS of the firewall.
Sounds to me like you disconnected a ground wire somewhere.
I also have an '84 SS and the 'puter is connected to a stand-alone harness which runs thru the lowest grommet in the firewall behind the PS front tire. If you remove the wheelwell you will see the wiring is connected to the 'puter in the car and all the sensors under the hood. The wiring just above it on the firewall is for the HVAC. The engine management wires run thru the bulkhead on the DS of the firewall.
Sounds to me like you disconnected a ground wire somewhere.
Ok I will go hunting for a ground wire I may have disconnected. By the way, since you have an 84.. There is a large (about 14 gauge) ground wire right above the ecm under the dashboard that has been disconnected since I got the car, and I cannot find anywhere it should have been connected to. The only thing I can think is it may have been part of the heat/ac unit that was deleted, but I am not sure. Just wondering if you may know what that runs to. Thanks a lot!
Well I tried and tried and I cannot find what caused my gauges to stop working. I have the entire dash out of the car now. So I have made a decision. Since they deleted the heat and ac. They deleted the cruise control. The ecm is useless now. And everywhere I look there is some wire hacked. So I have decided that I am going to go with more of a race car theme for my electrical, and take out nearly all of the factory wiring, and wire everthing to toggle switches which I will probably mount in place of the heat controls. I am going to switch over to aftermarket gauges and make my own cluster for them. I am even going to go with a ignition switch and push button starter switch. The things I need to try to retain are the power windows, and I would like to keep using the factory turn signal and wiper switch which is the column switch on mine. After I am done I would like the factory ignition switch to be only for unlocking the shifter.
Wish me luck. This is going to be a huge project for me, and probably take awhile. Any advise or heads up you guys can give me before digging into this will be greatly appreciated.
One specific question I have is what fuel level gauge should I buy to work with the factory sending unit on this? I don't know what the ohm rating is.
Wish me luck. This is going to be a huge project for me, and probably take awhile. Any advise or heads up you guys can give me before digging into this will be greatly appreciated.
One specific question I have is what fuel level gauge should I buy to work with the factory sending unit on this? I don't know what the ohm rating is.
je43278 said:
Not 100% but it sounds like the main power wire going to the fan control switch.
Good luck with your project. If the wiring is that butchered then you are further ahead to remove it and start again rather than dreading an electrical fire by patching what is left.
- Status
