I started a thread "May buy a non-running V-12 89 convert"....actually it's a 1990. If you read the thread I state the problem is No Spark. Well that has brought me to ask the question; does anyone know of any simple tests that can be done to check if the amp is okay? If not; does anyone know where I could perhaps mail them to someone who has the equipment to test them? Unfortunately, the local parts stores that have the diagnostic tester can't due the Jag Marelli ign amp/module. {If you read my other thread posting from today I delineate the parts installed and continuity tests performed.}
Can a burnt rotor short out the ign amps?

 

Don't know for sure but my guess would be unlikely.
Have you checked the resistance of the coolant and air temp. switches and the coils?
You seemed to have checked pretty well everything for continuity, did that include the grounding terminals on the amps? (opposite end of plug to +12)

 

I did not check the "grounding terminals" on the Amps...not sure what they are or what you refer to? When I tested the coolant sensor for continuity I got nothing...like open circuit. But maybe I had the scale on the meter too high. Did not test Air temp switch. The "Official" Jag Service Manual says the coolant sensor is a "secondary" input to the ECU and will not prevent starting...this is contrary to the "No Start" sticky. But again this is a Marelli ECU and he may have been referring to a Lucas system?

 

The Jaguar Marelli ignition amp is a Bosch unit 0 227 100 124

These ignition modules are pretty robust and it is unlikely for 2 to fail.

I would suspect a sensor issue, more likely a bad connection either CTS on the A BANK or the front or rear crank VR sensors, Front sensor is ignition timing and rear is engine speed, ALL must be good for the engine to run as these are primary inputs.

Check the gap and alignment on the VR sensors, gap is 0.042" max

 

On the ground issue Steve l was just referring to the spade on the amp plug with black wire. 4 spades in the row, one end of row is +12 the other end is ground. Just clutching at straws but it's always possible a ground eyelet has come adrift.
lve never had a problem with the Marelli but l thought l had read that bad air temp sensor will allow start but coolant won't. Not sure what resistance you should have at the sensor, l would maybe just try bridging the sensor plug terminals just see if it makes a difference. I believe the crank sensors are particular re air gap setting too.

 

Got it running!!!!!!!!!!!!!!! Burned rotor and bad Crank position sensor. May have had a bad coil as well, not sure about the Ignition Amplifier he replaced. See picture in my other thread "May buy non-running 89 Convert". Notice the picture of the boot. The Full set of Jaguar Service Manuals. Getting requests to scan and give to the forum...which I will do in the future. We're talking over 1,000 pages.

 

Well done........

The burning on the rotor was most likely caused by lack of maintenance ie replacing bad spark plugs. We are working with high voltage and it WILL find the path of least resistance to ground.

You DO NOT need to modify the Marelli distributor, just replace spark plugs on a regular basis and this will never happen again. You do not hear of this issue with Ferrari, Lambo or Porsche dual plug all use a very similar distributor, the Lambo guys are also using Jaguar rotors to replace the OEM.

 

Wow, I thought the modification was a sure fire...haha solution.
So how many miles between changing them?

 

I'm the 3rd owner and have all the service records which show no replacement of the rotor. My car has 267000km and it's on the 2nd rotor, I still have the original Marelli rotor which is in good condition. I only changed the rotor to see how the aluminium one from my 6.0L engine went.

 

Inspection of my new 90 XJS Convert revealed this...cracked hubs. I saw the bent strut and thought it may have been the cause; but the other hub is cracked as well...not as much, but still it's a crack!

 

Do you have emissions tests there? That rotor failure could of become an engine fire, gutting or replacing Cats with straight downpipes is worth looking into. I have a set of new coils if you need, they are the socket with a peg type, my car wouldnt take them as it was a slightly different socket.

 

Vancouverxj6, thanks for the offer, I don't need the coils. Now that it's running I don't "need" to test the amplifiers, but it would be nice to know if the one he replaced is actually good. I know I can just swap it back in to see. Since these are close to $300
a bench test would be a good thing to know.

 

I picked one up for £25. Check Kirby palms book out. There are replacement part numbers in it.

 

VE520225 Cambiare / 1637546 is what I use.

 

For those who find this thread in the archives, BIM124 / 0227100124 is NOT a direct substitute for Marelli module BKL3B. It's close, but it cannot be directly plugged in and work because the control pin on the BKL3B module is on pin 6 and the control pin on BIM 124 is on pin 5. The Jaguar harness connector has to be modified by sliding the connector pin 6 out of each connector and placing it in position 5. THEN the module will be commanded by the Marelli ECU and produce spark.

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Paul K.