Finally solved the no start problem!!!

So-- it would crank, but no fire. I took all of the advice I found on the forum, first suspected the digiplex boxes (after having confirmed there was fuel delivery), and so I took them off, cleaned all the ground points and ran dedicated ground wires to a lug welded to the chassis.

I eliminated the original quick-disconnect battery switch, and replaced it with a new and robust unit I had laying around from my racing days.

Verified 12.9 volts at the battery terminals.

I even ran a dedicated ground from the Fuel Injection box on the right side of the trunk.

Still -- no fire. But it cranked away just fine, and pulling the safety switch on the Fuel Distribution body-- did make the frequency valve buzz and the fuel pump whine.

Then it dawned on me that just because the motor cranked over with the ignition key --- didn't mean it was also completing the circuit to the ignition system. So-- I pulled the columns plastic off, and went through the PITA to remove the tumbler, switch, and steering column lock hardware. I sprayed some Contact Cleaner in the electrical parts as good as I could--- worked the switch by hand a few dozen times between spraying, and then persuaded it all back into the casting.

And Voila!!--- it fired right away and runs better than ever. I suppose the other stuff I did trying to fix it was needed anyway. I repeated the restart 6 more times over an hour to make sure-- but it appears I've fixed it!

One question, though. When I had the Digiplex boxes on the bench I tested them with a vacuum pump. One held vacuum with no problem. The other would leak down after about 4 seconds (with 15 inches applied to it). Anyone know whether there is a way to replace just that component?

I'm concerned that the current situation means I may not be getting full advance on one cylinder bank. And-- of course, having a slight vacuum leak on top of it. Not sure if that would adversely affect other engine performance

Any comments appreciated.

Michael
NorCal -- East Bay

 

Well done for fixing it! I think that would be a fair diagnosis vis a vis the advance. I think there is some kind of diaphragm in the Digiplex unit & it'll be old & splitting. There was a discussion about this a while ago vis-a-vis it not being repairable I think.

If it goes, unless you could pick up a replacement box at reasonable cost, it might be a case of looking at an upgrade & doing away with the digiplexes altogether.

 

Yes, but where do you get one? Seriously, you might give these guys a shout:

http://www.ecudoctors.com

They don't specifically list Ferrari, but my guess would be that the component that you need (the large white plastic gizmo in these photos) might be used in other ECU and/or they might know DigiPlex too.
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Steve,

Thanks for posting the interior pics. I was always curious what the bugger looked like inside. As someone else posted on another thread, I can see that the conformal coating they lathered on would make servicing this unit a major pain.

I'll contact that Outfit about the component:

http://www.ecudoctors.com/

I suppose the best way to confirm whether that one failing unit is having a real effect on the advance curve is to try a timing light on both banks and bring the engine speed up.

Thanks again,

Michael

 

Just a thought here, but if the vacuum leak in that little canister is along the molded seams, perhaps it could be sealed up with some epoxy or silicone sealer. Might be worth checking the actual source of the leak, especially if the component is now "unobtainium" or so expensive that you have trouble catching your breath when you hear the price.

 

I had a problem where I would start the car, drive along for a while, and the car would just die while driving. When I cranked it over, it would start again. It was intermittent and drove me crazy. One day it did it on the highway at 70 MPH. When the engine died and I was coasting, with the wheels turning the engine but no ignition, in total frustration I jiggled the key and it started running again.

VOILA!

I had the same problem you had...just dirty contacts in the ignition switch. Pulled the switch, cleaned the contacts with good ol' Radio Shack contact cleaner, and never a problem since.

Birdman