’97 XJ Grand Cherokee, Anti-theft system, no power / ground to Injectors

Expert advice please! ’97 XJ Grand Cherokee, Anti-theft system, no power / ground to Injectors

Hi from sunny South Africa. I hope there is someone on here who has expert knowledge of the ECU and Anti-theft system on this model. (SA Export model)

Background - Overnight the XJ developed a no-start condition. No guages. Fuel pump running continuously. Diagnosed as defective ECU. Installed new ‘donor’ ECU. Guages working, ASD and fuel pump relay’s now prime correctly. On first 3 cranks engine fires, but dies after 1-2 seconds. After 3 attempts did not fire at all.

Diagnosis - The engine fires briefly when ‘Engine Start’ sprayed into inlet manifold, so problem diagnosed as as a fuel supply / injectors problem. Tested voltage to injectors and circuits. No/low power to injectors and no grounding by ECU. No error codes though.

Expert advice received - after 3 attempts to crank using incorrect keys (i.e. that do not match the VIN number stored in the ECU / SKIM module) the anti-theft system immobilises the vehicle by disabling the ECUs injector control circuit.

So, I then had the correct (original) VIN coded into donor ECU so that it matches the original keys and SKIM. The anti-theft warning lights go out when vehicle is opened with original key / FOB, but still no fire or start. Further advice received was that the anti-theft system will only reset the ‘disabled injector status’ after the key has left in the ‘on’ position for over 2 hours.

I performed this procedure, but engine still does not fire (although it does when ‘Engine Start’ is sprayed into inlet manifold).

Can someone please advise 1) if the above advice and remedies are factually correct 2) if there are other procedures needed to reset the injectors’ control circuits 3) any suggestions on how to get the injectors operating again. Thanks!

(PS. I am now completely bald as I have pulled out all my hair over this issue and would really like to get this car going again!)