Ferrari 412 Diagnostic Port

It connected to the Ferrari Jofatron. Gave RPM and ignition timing data. Possibly dwell too because it worked on early conventional ignition cars too.

We called it the Jokeatron. It was the only tool that could tell you if the ignition advance in Microplex and Digiplex were working correctly. Its about all we used it for.

One pin is 12V and we used it for a power source for other test equipment more than anything. In fact we made a 12v out wire on the Jofatron connector cable to make it easy and discovered with it connected and not grounded it acted as an antenna for RFI on the Microplex systems.

Its supposed to have a rubber cap to prevent corrosion.

Found a picture. Also has cylinder kill buttons lower left.

Upper left is to enter program code for specific vehicle.

 

Yes. Standard feature on automotive oscilloscopes since the 50's. Not used these days because of catalytic converters.

 

It's just some of the ignition system input signals going to the Microplex ECU and output signals generated by the Microplex ECU:

1-6 Coil terminal 1
7-12 Coil terminal 1
Coil terminal 15 (this is the handy +12V with key "on" signal that Brian mentioned)
TDC sensor signal +
TDC sensor signal -
chassis ground
(some pins are duplicates of other pins)

 

Not with the certainty that I'd like to have. I don't have the 412 wiring diagram book, and all I have is the schematic for TR that use the same MED120B Microplex ECU as the 412. Unfortunately, the symbol for this connector on the TR schematic doesn't convey whether it's drawn looking at the pins like your photo or looking at the backside of the connector (and my TR is a later one using the MED120B/D Microplex ECU that does away with this connector and has a 3-pin Diagnostic pigtail on the Microplex unit itself so I can't figure it out for myself). The asymmetry of the pin pattern does allow me to say with some certainty where the power and ground pins are:

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I don't know how hard it is for you to get to the coil terminals 1 and the TDC sensor connector on 412, but just using an Ohmmeter you should be able to measure from those locations to the pins to determine who's who.

 

None. All those are built in and will be selected on running circumstances and which market setting is selected based on wiring.

 

Yes.

 

What? That graph is not perfectly clear, understandable, and easily readable? That's not like Ferrari's usual technical documentation at all.

They did manage to leave off some important labeling on this one -- the "steps" in the lower right corner should be labeled 1 thru 9 with the lowest being 1 and the highest being 9.

It's nine separate curves laid on top of each other

"A" represents the intake manifold vacuum applied to the Microplex ignition ECU (in millibars):

When A is below 70 millibar = use curve 1
When A is between 70 and 160 millibar = use curve 2
When A is between 160 and 250 millibar = use curve 3
etc., up to
When A is greater than 600 millibar = use curve 9

Although these curves do not include the effect of an idle microswitch (if so equipped) -- at the idle position, a closed microswitch typically retards the timing a fixed amount (which is why the idle timing given in the OM specifications does not match what the curve from this graph for a normal idle vacuum at 1000 RPM would indicate that it would be).

PS Since 412 was only sold in a euro version, there is only one set of these curves for a 412; whereas, other F models (that come in more versions) have different sets of curves depending on the version.

 

Steve, 412 is the same part # used in TR. We had a lot of trouble with them detonating on US gas and changed the market ID wire to put it to the US curve and it helped substantially.

 

Makes sense, since getting the 98-100 RON (93-95 AKI) fuel that the 412 OM specs probably wasn't even available in the US (at regular gas stations) at the time. I need to correct myself. After reviewing Diagnosis Sheet N. 1, it indicates that there are different ignition maps available from the MED120B for 412 Standard (euro) and 412 CH (Swiss) -- do you know of a reference showing the 412 CH ignition map?

 

Mine has no curve graphs but shows US and CH using the same. market ID connections

 

Can't agree -- my copy of Diagnosis Sheet N. 1 shows each of the six has a different pattern of ground or open for the three pins used for "vehicle identification" per this table:

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Does your copy show something different for these three identification pins?

 

No. 23 is on the next page and did not see it. Have not dealt with this since 87. Been a while.