308 GT4 Ignition Problem

My 79 Euro spec 308 GT4 has recently developed an intermittent power loss problem. It only occurs when the engine is properly warm and the power loss is accompanied by the rev counter stopping working.

When the power is down I can disconnect one coil at the HT output and there is no change to the engine running or rev counter. If I disconnect the other coil the engine dies completely.

So I suspect a bad coil - the one on the right in the photo with both coils visible.

It was fun to get out due to the location of the bolts on the underside and the fuel tank being in the way, but is was possible to get it out without removing anything else using a 10mm socket with a UJ and extender on it.

Having removed the coil, I'm now in a quandry as to which type to replace it with as there seems to be 2 options:
a) BK2A for points based ignition
or
b) 30817225 for transistor based ignition

From looking at this thread https://www.ferrarichat.com/forum/threads/rebuilding-the-308-electronic-ignition-sm805a-distributor-marelli-aei200-ignition.435679/ I'm erring towards b).

Can anyone advise based on the 2nd pic? I'm erring towards b).
Also, any other potential causes?

 

You could also swap just the coils:

if the tach keeps working when the power loss occurs = bad coil now on the left side after the swap (as the brown wire on the coil on the right is the tach signal)

if the tach still also fails when the power loss occurs = more likely a bad electronics module on the right side.

 

Thanks Steve, that is a good suggestion.

 

I would also check some of those wires for corrosion where they go into the spades. On old stranded wire, it's not uncommon for the wires to corrode internally and this can cause resistance in the leads.

Ray

 

It looks just like a coil/ignition module off a Fiat Spider 2000 1979 on. The ignition module is a GM part - used to be available almost everywhere and maybe still is. The ignition modules do get heat sensitive- i.e. fail when hot, work when cold. I always carry a spare in my Marelliplex cars. At $15-20 a module I would just try swapping them out- a trivial job, but do use the heat sink compound.

In an Abarth I used to co-drive in we finished a rally stage by pouring our drinking water over the coil when the car stopped...

Good luck,

Phil

 

Well the new coil (for transistor ignition) works, but didn't fix the problem. Is the ignition module you refer to the amplifier like in the pic Phil? Because those are the exact symptoms I have.

 

Yes, that is one. There seem to be a few different brands, with some claiming to be high performance (and costing more). I have always just used whatever the parts store has supplied. I must have replaced 4 of these over the years, all with the ignition failing when hot symptom. They normally come with a little package of heat-soak compound to put under them when screwing them to the heatsink/coil mount. I think that big alloy coil mounting casting is probably a hint that the manufacturer wanted to keep these things cool!

I believe the coil is matched to these in that not just any-old-coil is suitable. I have never replaced a coil so never fully figured out the specs. etc.

Good luck!

Phil

 

Thanks Phil.

 

Hi there. I've just posted an almost identical problem with my 308QV. I should have perused first! When you say "power loss" do you mean partial? Or complete engine cutout, because that's what mine is doing, which makes me think the problem is somewhere *before* the coils.

 

Just partial power loss - one bank of cylinders.

 

Well the part number of the coil was discovered when taking the retaining band off: BAE207A
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The original ignition amplifier is a GM part (bottom) with Magnetti Marelli branding printed on it.

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Just an update on this issue. It turned out to be more than 1 problem in the end. A distributor rebuild and an alternative make of ignition amplifier did the trick. I put 2 different Hella ones on, and my mechanic another probably from the same factory in China - all faulty! In the end he found one from Germany that worked.