308 misfire after engine out. COIL WIRING

What year/version 308?

There is a decent schematic of the ignition system in the OMs Section 3, or the whole wiring diagram is in Section 5.

 

The funny thing is that if you look at the 308 manual and compare it to the wiring diagram on the actual coils, they are different! (at least they were on my GT4's coils.)

 

Hey,

Have you read thru' this thread? http://ferrarichat.com/forum/showthread.php?t=250827

Turns out Tom had a different problem (one bank of cams 180deg out!) but there's a lot of helpful comments that may relate to what you're seeing.

Good luck, Cheers,
Ian

 

(Per your 216/81 OM schematic)

The yellow (G) wire goes to the "+" terminal (terminal 15) of both coils -- this line is +12V when the key is "on".

The green (V) wire goes to the "-" terminal (terminal 1) of the 1-4 coil -- what is important is that this V wire also goes to pin 11 on only one of the DigiPlex ECUs, so the 1-4 TDC sensor must be connected to pin 1 (L blue wire) and pin 5 (V green wire) of the same DigiPlex ECU (these wire colors are for the ECU connector and the wiring harness side of the 1-4 TDC Sensor connector -- not for the 1-4 TDC Sensor itself).

The yellow/black (GN) wire goes to the "-" terminal (terminal 1) of the 5-8 coil -- this GN wire also goes to pin 11 of the other DigiPlex ECU, so the 5-8 TDC sensor must be connected to pin 1 (N black wire) and pin 5 (G yellow wire) of the same DigiPlex ECU (these wire colors are for the ECU connector and the wiring harness side of the 5-8 TDC Sensor connector -- not for the 5-8 TDC Sensor itself).

One caveat is that often on schematics they switch things like 1-4 and 5-8, but the bottom line is that, if terminal 1 of the coil for the X-Y bank is connected to the DigiPlex ECU pin 11, then the TDC Sensor for the X-Y bank must be connected to pins 1 and 5 of that same DigiPlex ECU.

Here's a jpeg to identify the TDC Sensors (maybe you'll be lucky and one is just unplugged ):
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If it all seems wired up OK, but you still have a dead bank:

1. Unplug and measure the resistance of the TDC Sensors -- should be ~700 Ohms (not infinite Ohms nor 0 Ohms). You can also physically swap the TDC Sensors to see if the problem follows them or not.

2. Try swapping the DigiPlex ECUs -- if the problem follows the ECUs that would be a bad sign for that ECU; if the problem doesn't follow the ECUs then it must lie elsewhere.

Good Hunting!

 

The circuit below (from the Ferrari wiring package) might help follow Steve's description. GL
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Hey guys, I just came across this diagram, and I need to know what 2 components are, and where they are located. These are new components that are not on my previous diagram.
1. Connector for TDC Pickup 132 at the top of the diagram
2. Temperature Switch 73 at the bottom of the diagram.

Can anyone help with this?

Thank you.

 

The "Temperature Switch" is a bimetallic thermoswitch mounted in the coolant expansion tank on US version 308i-2V and 308QV. What version is your 1984 308QV?

 

Mine is a Euro QV.

 

There's no "temperature switch" on an (unmodified) euro version 308 QV. Your stock ignition schematic is shown on page 74 of your 248/82 OM.

 

Swap the crank sensors..bank 1 to bank 2..yes its a pain. If the problem follows..then you have found your issue.