Been reading the section on the Marelli failure in the "Experience" book by Kirby Palmer. On page 165, they start talking about the "Ignition Failure Sensor" designed by Andrew Corkan....or what I like to call "The Marelli black box".

The Ignition Failure sensor is designed to light up a light or one of a pair of lights to alert the driver to a failed bank which is all fine and well, but what really caught my eye was on page 168, where it describes an automatic shutdown mode to kill power to the ignition in the event of a failure..or even better yet...a couple paragraphs down it describes a Limp-home mode; where it kills the fuel flow to the dead bank, allowing the driver to limp home the vehicle (or at least get it out of traffic).

Pardon the pun, but it seems that short of replacing the distributor with a Lucas unit (also covered in this section of the book), this is probably the "Cat's Meow" to guard against the Marelli failure and possible engine bay fire.

I'm thinking of adding this to my list of projects for my XJS. I was wondering if anybody else has attempted to build this and how did it work.

howlinowl

 

I bought the components and tried it, but I couldn't get it to work :-( Thats probably due to the fact that I've not made any circuit boards since I was at Uni 20 years ago.....

It would be neat to get it working though. I have a few other tell tale lights in the car for various other things (fan running, fuel pump running) so having 2 for ignition would be nice. If you try it and get it to work, I'd be more than willing to pay for a duplicate !!

I was thinking about a simpler way to do it...... just buy 2 of those spark plug tester things that you put over the HT lead and it flickers when current is on the wire, ie Then use a fiber optic to bring the flickering light into the cabin....... or maybe you could even pull the thing apart and mount the light in the cabin and extend the wires ?

 

I read that as well and thought about doing it. But since I experienced a fire from a bad coil I don't need any lights or warnings. The loss of power when one side quits is unmistakable. I actually pulled over and looked under the hood, but I wasn't aware of what was going on. I started back up and drove 1500 feet, then it caught fire.

 

I have always had a FF code about 2 or 3 weeks before a coil died. I can't remember which code, but I have had 2 marelli cars for a long time... It seems that they give a warning before dying.

Dave
Atlanta

 

Could be ff18, that's what I got, twice. The car did it a week before as well.

 

That sounds right... I should have made a note of it in my manual.

Dave
Atlanta

 

Keep the maintenance up to it and you will not have a problem with one side quitting.. Just pull the cap and rotor every time you service it and you will pick up most problems before they happen.

 

If I can remember correctly, the ff18 is something to do with excess heat in the manifold, which would make sense.