Suggestions please. I am getting an ff33 dtc code which is checks ecm output to fuel injectors. I am getting good spark and have good fuel pressure. When I turn the key to the on position I get 12 volts to both fuel injectors pins. I have performed the dtc ff33 diagnostic procedure as per the jaguar aj6 diagnostic guide. The test resulted in all the wiring being good and them recommends a substitute ecm which I did with no change. What confuses me is that with the key on there is 12 v power to both pins, is that how it should be?
Also should there be a ground wire to the ecm case? I checked all the ecm power grounds and they are good and cleaned all grounding points in the engine bay as well.
Thanks, John

 

The 12v to both pins (assuming the injector is attached to the connector) is because the loom is live from the 12v feed to the injector loom, through the injector and back as far as the ECU. Then the ECU activates the injector by earthing the loom to the ECU's earth pin.

 

Thank You Greg,
How would you suggest I proceed in testing?
John

 

If you use a mechanic's stethescope, or a noid light, you can hear/see if the injectors are clicking.


The report back. Facelifts have all sorts of ways of not starting, lots on the forum to search for, and I know nothing about them. However it is worth checking that the relevant earth pin (or pins) in the multiplug connector to the ECU is making contact with the ECU pin and has continuity to the injector loom.

 

Thanks Greg, you have been a big help.
John

 

John,

You've mentioned the fault code but you haven't mentioned what are the symptoms of the car? Does it not start? Or is it starting but running badly? Or is it running fine?

I'm surprised at Jaguar's recommendation of changing the ecu, just based on a fault code. That seems really excessive and expensive. The ecus on 4 litres are not know problem areas. Corrosion on plug pins, possibly; but a failed ecu is unlikely. Don't change any more parts unless you're absolutely sure they are at fault.

If the car is starting and running, I would just clear the code, run the car normally and see when, or if, the code returns.

Cheers

Paul

 

Hi Paul,
Crank but no start, getting spark and have good fuel pressure. New CPS, fuel pump, o2 sensor, ignition coil, ignition amplifier, and coolant temp sensor. In the Jaguar AJ6 diagnostic guide I have performed the procedure for dtc ff33. This procedure deals primarily with the wiring from the ecm to the fuel injectors and the grounding pins on the ecm, which all tested good, so at the end of this procedure Jaguar says to try substitute ecm. However the procedure only does a resistance test on the fuel injectors and no testing of the fuel injectors solenoid, which I will test tomorrow. AS I mentioned I had bought a used ecm and after install no change. Also I have cleaned all grounding points and checked all fuses and relays. So while I am testing I do not have the ecm remounted on the B post on the passenger side, so should the ecm case be grounded? I have been trying to figure this out for 4 months.
John