Dave_GSR1.8
Well-Known Member
So, I have an starting problem that I think is the ECU, based on the testing I have done.
To set the scene, I am running ECMLink v3 Lite in a GSR ECU with standard bolt on mods (fuel pump, fuel pump wiring, injectors, EVO AFM, FMIC, exhaust, but sadly still with TD04). I have run this ECU for three years without issue, this problem started about a month ago .
The issue is that the ECU intermittently goes into a fault state whereby the CEL does not come on with ignition on; the engine will crank but will not fire. To fix this I have to remove and refit the fusible link for the MFI relay (no 2 in the engine bay fuse box), after which the ECU works properly again till the fault reoccurs.
So, I got out the voltmeter and back probed all 8 pins on the MFI relay (a new one because I was led to believe that this was the problem, it wasn’t...) and Pins 60, 36 and 12 on the ECU, with the ECU in both its "fault" state and when working normally.
The results are summarised in the attached PDF attachment.
In summary, my thinking is that:
The ECU is not switching off correctly when the ignition is switched off; this is an intermittent fault, but happens often enough to be an issue (at least four or five times a week).
This is based on;
- the voltages being read at the ECU (pins 12 and 36) and MFI relay (in particular pins 2, 3 & 6), when the ECU is in the fault state;
- the fact the battery will go flat if the car is left in this state for more than 48 hours;
- the fact that disconnecting the ECU from backup power causes it to reset and function correctly until the fault occurs again.
- the fact that there is fuel pressure at the fuel rail, when the ECU is in fault condition and engine is cranked
- the fact that there is spark at plugs, when the ECU is in fault condition and engine is cranked
- the fact that the injectors do not fire when the ECU is in fault condition and engine is cranked
So, has any one else ever had this issue? Or have any ideas other than the ones I have had? I am wondering if there is anything I might have missed or overlooked?
To set the scene, I am running ECMLink v3 Lite in a GSR ECU with standard bolt on mods (fuel pump, fuel pump wiring, injectors, EVO AFM, FMIC, exhaust, but sadly still with TD04). I have run this ECU for three years without issue, this problem started about a month ago .
The issue is that the ECU intermittently goes into a fault state whereby the CEL does not come on with ignition on; the engine will crank but will not fire. To fix this I have to remove and refit the fusible link for the MFI relay (no 2 in the engine bay fuse box), after which the ECU works properly again till the fault reoccurs.
So, I got out the voltmeter and back probed all 8 pins on the MFI relay (a new one because I was led to believe that this was the problem, it wasn’t...) and Pins 60, 36 and 12 on the ECU, with the ECU in both its "fault" state and when working normally.
The results are summarised in the attached PDF attachment.
In summary, my thinking is that:
The ECU is not switching off correctly when the ignition is switched off; this is an intermittent fault, but happens often enough to be an issue (at least four or five times a week).
This is based on;
- the voltages being read at the ECU (pins 12 and 36) and MFI relay (in particular pins 2, 3 & 6), when the ECU is in the fault state;
- the fact the battery will go flat if the car is left in this state for more than 48 hours;
- the fact that disconnecting the ECU from backup power causes it to reset and function correctly until the fault occurs again.
- the fact that there is fuel pressure at the fuel rail, when the ECU is in fault condition and engine is cranked
- the fact that there is spark at plugs, when the ECU is in fault condition and engine is cranked
- the fact that the injectors do not fire when the ECU is in fault condition and engine is cranked
So, has any one else ever had this issue? Or have any ideas other than the ones I have had? I am wondering if there is anything I might have missed or overlooked?
