The car has sat for about 3 years with no battery. It ran before, now it won't start. I've traced it down to the ECU not grounding the main relay to kick on the fuel pump. Before I tear this thing apart, is it possible that the ecu memory was wiped from no power for so long? It's a chipped P28 on Chrome.

 

Clean and tighten the G101 ground on the thermostat housing.

 

I will, but I checked it with a multimeter and got less than 1ohm.

Correct my if I'm wrong, that's the group of 3-4 wires that's bolted to the thermostat housing via what looks to be a double ended terminal end?

 

Correct.

Does the engine crank strongly?

 

Yes, and sometimes starts but won't stay running. That only happens with the pump jumpered on. No CELs either.

 

Power capacitors can fail even when the ECU is not being used or has power applied to it... just like batteries in a flash light. You can leave it in a drawer for years, and when you need it, it doesn't work. So you remove the end cap and remove the batteries only to find greenish-white chalk and swollen battery case bodies.

Try another known-good ECU and see if everything is alright.

 

Alright I'll try that. It's tuned on chrome, would the eeprom chip go bad in this case or could I swap it to another chipped ECU and be good? Assuming it's P28 to P28.

 

It is unlikely that the EEProm chip would fail. If it is a really early style and has an UV window on top and is exposed and not taped over... maybe it could be blanked. You could certainly try to use it in another socketed P28 and cross your fingers.