Injections not opening

Just FYI, if crawling into the trunk to measure against those pins is a pain in the “A”… you can always crawl in there, jumper the same pins on the ECU connector side making the loop on the opposite side, and then try to take your measurements out in the engine bay. That might be easier.

~Paul K.

Hi Paul:
Well the first ray of sunshine has finally arrived… I jumped out pins #19 and #5…in trunk and the CTS plug shows continuity…I therefor believe no open circuit in wiring from cts plug to ECU.

Before the above procedure I unwrapped all black wire-wrap to, perhaps a bad connection at TPS, it showed none at the three-way plug inlet.
Does this give any new insight to my fuel igniter issue…
Thanks, Sloth (Ivan)

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Sorry it’s been a bit getting back to you. I’m re-looking over both threads, and realizing that there’s one thing that hasn’t exactly been verified that’s crucial for the EFI computer to inject fuel.

With the exception of your initial comments that the car tried to fire up after … I guess… pumping the gas (which may have engaged a WOT injector burst)… We have NOT 100% confirmed that you have ignition. And it’s not so much confirming ignition for it’s own sake (which is important) but to verify that we actually have an RPM pulse from the ignition amp on the white wire to pin 18 of the ECU. It’s entirely possible that the wire itself can be OK, and that we see voltage on it as 12V passes through the +side of the coil to the - side for charging, but we never see spark or a pulsed open connection from ground that causes coil field collapse, spark, and the RPM pulse to the ECU needed for fuel injection.

Otherwise we seem to have checked the crucial bits… the temp sender wiring/sender, the injector wiring and wiring through the ballast resistor. The other inputs (load switches, throttle pot, air temp sensor, o2 sensors, even map sensor) are all trim related and at at least individually unplugged will not stop a car from starting. It just won’t run right.

The best way to verify that pulse to the ECU is an ossiliscope… but we can be fairly certain without one as long as you have a good spark from the king lead of the coil when starting the engine. If you do not have this, that would be why the EFI system isn’t working, and we can begin looking at a problem in the AB14 amp box, or the coil as a solution.

~Paul K.

You’ve been through some of this but so I don’t forget (and I can ref this easier in the future).

Sort of a master checklist for checking the pinout/wiring of the ECU connector:

6CU/16CU ECU Connector Multimeter Test Chart:

Unless otherwise stated test should yield the same results with key on or off (test both ways).

Long row of pin-sockets starting from the right moving left:

  1. Continuity to ground Y/N NC
  2. N/C
  3. Full Load Switches:
    Normally Open Circuit? Y/N
    Ground w/Throttle @ WOT? Y/N
  4. Diag Wire: NC / Open Circuit? Y/N
  5. CTS Sensor Input (must be tested w/pin 19)
    Has continuity at CTS plug with a jumper across pins 5&19? Y/N
    Has a temp sensor chart consistent OHM value across 5&19 when CTS plugged in? Y/N
    https://www.jaguarfuelinjectorservice.com/Testing%20Testing%20the%20Jaguar%20Coolant%20Temperature%20Sensor.htm
    No voltage on either pin w/key on. Y/N
  6. “A” Bank O2 Sensor. No voltage w/o engine running. Y/N
  7. TPS Wiper: (must be tested w/pin 20)
    0.5K to 4.5K Ohm between pin &&20 when capstan actuated between closed and full throttle: Y/N
    No voltage w/ key on. (ECU would usually provide a voltage) Y/N
  8. B Bank Injectors 1,3,5 “ON”
    +12V with key on? Y/N
    Has continuity with pin 9? Y/N
    Has 0.53 to 6.0 Ohms resistance to pin 11? Y/N
  9. B Bank Injectors 1,3,5 “ON”
    See tests for #8. Should test the same
    All test for #8 worked thus #9 tested? Y/N
  10. O2 sensor monitor line.
    Open Circuit? Y/N
    No Voltage? Y/N
  11. B Bank Injectors 1,3,5 “HOLD”
    Falls under tests for #8 & #9. Should test the same
  12. A Bank Injectors 1,3,5 “HOLD”
    Falls under tests for #13 & #14. Should test the same
  13. A Bank Injectors 1,3,5 “ON”
    +12V with key on? Y/N
    Has continuity with pin 14? Y/N
    Has 0.53 to 6.0 Ohms resistance to pin 12? Y/N
  14. A Bank Injectors 1,3,5 “ON”
    See tests for #13. Should test the same
    All test for #13 worked thus #14 tested? Y/N
  15. Fuel Pump Relay Control
    +12V with key-on? Y/N
    Continuity to pin 85 of FPRelay socket (test not needed if +12v avail on key-on) Y/N
  16. Ground. Continuity to ground. Y/N
  17. Ground. Continuity to ground. Y/N
  18. Engine Speed RPM via white shielded wire from amp.
    Has +12V with key-on. Y/N
    Has oscilloscope wave w/ voltage falling to 0V when cranking? Y/N
    Check continuity of wire to engine bay? Y/N

Bottom pin-socket row 19-35 right to left.

  1. TPS and CTS Sensor Ground:
    Partial test w/ pin #5 above complete? Y/N
    4.5K to 5K Ohms test across pin#19 & pin #20? Y/N
    No voltage Y/N?
  2. TPS Sensor Connection (ECU would usually supply +6V signal).
    See test for #19. Complete? Y/N
  3. Air Temp Sensor Input (Must be tested w/ pin 20)
    Continuity across Air Temp Sensor connector pins w/ECM pin socket 20&21 jumpered? Y/N
    Expected OHM range between pin 20&21? Y/N
    http://jaguar.professional.org/thermistor/AirTemp.php
    No voltage
  4. ECU Power from Main Relay.
    +12V with key-on. Y/N
    Continuity to pin 87 of Main Relay if 1st test fails? Y/N
  5. O2 Sensor Shield Wire:
    Continuity with ground? Y/N
    No voltage Y/N
  6. “B” Bank O2 Sensor. No voltage w/o engine running. Y/N
  7. "O2 Sensor Disable Plug.
    +12V W/Key On.? Y/N
    Open Circuit w/ Key Off? Y/N
  8. Start Signal from Starter Relay
    +12V with engine cranking. Y/N
    0V in any other position. Y/N
  9. B Bank Injectors 2,4,6 “ON”
    +12V with key on? Y/N
    Has continuity with pin 28? Y/N
    Has 0.53 to 6.0 Ohms resistance to pin 29? Y/N
  10. B Bank Injectors 2,4,6 “ON”
    See tests for #27. Should test the same
    All test for #27 worked thus #28 tested? Y/N
  11. B Bank Injectors 2,4,6 “HOLD”
    Falls under tests for #27 & #28. Should test the same
    30 A Bank Injectors 2,4,6 “HOLD”
    Falls under tests for #32 & #32. Should test the same
  12. B Bank Injectors 2,4,6 “ON”
    +12V with key on? Y/N
    Has continuity with pin 32? Y/N
    Has 0.53 to 6.0 Ohms resistance to pin 30? Y/N
  13. A Bank Injectors 2,4,6 “ON”
    See tests for #31. Should test the same
    All test for #31 worked thus #32 tested? Y/N
  14. N/C Unused
  15. Ground.
    Continuity with ground? Y/N
    No voltage Y/N
  16. Ground.
    Continuity with ground? Y/N
    No voltage Y/N
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Hi Paul:
Well things may be looking up… I felt I wanted one more try at basic engine behavior…so I called my next door friend and helper to handle the starter…I pulled lead from coil to distrib. and got the bluish and most powerful spark I ever saw. Reconnected the lead and engine ran for at least eight seconds…I was very happy now it does not start…checked ohmage of coil at + terminal and minus terminal…both read around 19. 3 ohms.
could the wiring in coil be worn.??
I saw somewhere the coil has to mate with the power amplifier…I believe mine does not. I believe my coil is not the proper one.(although the auto parts people say yes.)
Fill me in on a proper coil to amplifier relationship (I believe it’s my problem).
Thanks,
Ivan

I’ll have to continue this later… going to bed now, but 19.3 ohms is massively high. 0.8 to 1.0 ohms i believe is expected of the round coil 2 coil system and 0.5 to 0.6 ohms with the single coil upgrade replacement.

~Paul K.

For any car cranking and not starting the majority of the time it is an ignition problem in general.

19.3Ohms is way high and certainly indicates a bad coil. You should test both coils individually. (I believe Kirby’s book specs the individual round coils at 1.2 Ohms).

Together wired in parallel they should have had about 1/2 the OEM spec resistance of an individual coil… so about 0.5 Ohms. That’s why a modern 0.5/0.6 Ohm single coil can charge deeply enough to substitute for the two coils.

I believe DAC 6093 is the single coil upgrade PN.

Re matching the coil to the amp… this is nominally a good instinct, however, Jag has offered the single coil as a replacement in the Lucas system, and the GM amp inside the AB-14 body works with a wide variety of coils. Unless the amp has been replaced it is older tech though. Many folks dive inside and replace it with a modern upgrade unit and a coil to match (which should ALWAYS be a low Ohm coil.). Low Ohms usually means it can take more amps in for a charge. The amp does need to be able to handle that.

~Paul K.