hi, I know I haven't gone to the new member section. But I do need help. I have a 1976 Jaguar xj12l I am working on. The owner of the car connected a battery booster to it backwards. I am left to figure out why it will not start.
there is a new distributor and coil in the car with a new trigger switch "reed switch" with three wires coming off of it. the car has spark to the distributor from the coil. So it is to my knowledge that the sensor is working correctly.
The white and black wire coming to the coil on the negative side flashes with a test light just fine. and this wire I believe is also the wire that sends signal to the pcm for injector pulse. I checked the wiring to and from the pcm to the power amplifier on the radiator support as well. it checked good.


I have also took the injector harness off of the engine and inspected and repaired any shorts or brittle wiring.
As it stands right now, the car has 12v on one side of the injector harness, and cranking the other side has a slight "ground " or negative flash using a power probe circuit tester. there is no light up with a injector noid however. Using the power probe to ground (pulse) injector harnesses while cranking, the car attempts to start, but the task of being a human pcm is too much to get the car to run. ha ha


So to summarize, there is power to the injectors but not enough ground to properly pulse the injectors. I have opened up the pcm and the injector power amplifier to check for any kind of burned out or poor connections, to no avail. I have 1.8, and 2.0 v coming from the pcm to the power amplifier under crank condition. I also have no idea what the spec for those lines is.


Any help as to find where the injector pulse will be much appreciated. Thank you very much in advance. I know there is a wealth of knowledge on this site from my time lurking.


Thanks again

 

This might be useful: -

JAGUAR V12 FUEL INJECTION 1975-1980 - D Jetronic / AJ6 Engineering

 

Still having issues as to what the signal to the power amplifier is supposed to be. BUMP

 

If it is a 3 wire trigger board, as you mention, there is NO power supply to that board.

The magnet in the heel of the rotor arm is the trigger for the reed switches.

Many replacement rotors DO NOT have that magnet, NO idea why, maybe the aftermarket only caters for the HE engine/system, I have been in aftermarket spare parts fro 51 years and NEVER found the PreHE rotor from any supplier except Jaguar, or Jaguar Parts Suppliers.

Without that magnet there is simply NO injector pulse, no iffs no buts.