ostlar
03-06-2025, 12:45 PM
Hi!
I've got a 1990 Galant with a 2,0L 4G63 with the EFI Multi.
I parked it in the garage on Sunday, and just a couple days later, it wouldn't start at all.
It just cranks, with no sign of firing, except with starter fluid.
Here's what I've diagnosed so far:
It cranks and starts with starter fluid, so spark and air is present, just missing fuel.
It starts for a bit if I manually set power to the injectors to release the fuel pressure from the rail.
Fuel pump works, good pressure at the rail
Sounds like good compression
Crank sensor in the distributor works
Injectors are all tested and work individually, but doesn't seem to get any pulse from the ECU.
They have +12V on pin 1, and the ECU grounds them with the NPN transistors. These seem to have proper ground, I opened and measured them. Unfortunately I don't have an oscilloscope to check the pulses.
Sensors like the MAF get power, but at 12,5V instead of 5V in the service manual? Weird.
Diagnostics code is constantly on, which reads ECU fault. This is my main concern.
ECU has both power and ground where it should
ECU looks completely fine
Check Engine Light is on, and does not shut off after 5 seconds as it should
MPI Relay has power and works as it should, checked continuity
I'm completely lost on what else to check, does anyone have any suggestions?
I might be able to get my hands on another ECU this weekend, I know a guy with Galant parts laying around.
Might also order some capacitors, as they could be the culprit.
I've got a 1990 Galant with a 2,0L 4G63 with the EFI Multi.
I parked it in the garage on Sunday, and just a couple days later, it wouldn't start at all.
It just cranks, with no sign of firing, except with starter fluid.
Here's what I've diagnosed so far:
It cranks and starts with starter fluid, so spark and air is present, just missing fuel.
It starts for a bit if I manually set power to the injectors to release the fuel pressure from the rail.
Fuel pump works, good pressure at the rail
Sounds like good compression
Crank sensor in the distributor works
Injectors are all tested and work individually, but doesn't seem to get any pulse from the ECU.
They have +12V on pin 1, and the ECU grounds them with the NPN transistors. These seem to have proper ground, I opened and measured them. Unfortunately I don't have an oscilloscope to check the pulses.
Sensors like the MAF get power, but at 12,5V instead of 5V in the service manual? Weird.
Diagnostics code is constantly on, which reads ECU fault. This is my main concern.
ECU has both power and ground where it should
ECU looks completely fine
Check Engine Light is on, and does not shut off after 5 seconds as it should
MPI Relay has power and works as it should, checked continuity
I'm completely lost on what else to check, does anyone have any suggestions?
I might be able to get my hands on another ECU this weekend, I know a guy with Galant parts laying around.
Might also order some capacitors, as they could be the culprit.