I had this over in the 308 section, thought I would ask over here 78 308 GTS Car quit running, the first and second circuits on my fuse block are shot, brown and melted, not that bad looking but everything on those circuits is dead. Its the instruments, windows, and electrovalve, etc. Shortly before the car died, both slow down lights came on and at the same time i heard the airbox flap shut, then lights went off and flap opened. A few minutes later same thing then she crapped out. new birdman fuseblock ordered Question is: what is on the 1 and 2 circuits would prevent the car from firing up? Reading the descriptions, I can't see what would, except when the power is cut to the electrovalve the airbox flap closes and therefore there is no air to the carbs? I would pull the airbox cover and see if it starts, but I am 2000 miles away right now and just curious. TIA, Geno more details here http://www.ferrarichat.com/forum/showthread.php?t=291996
That's because the descriptions only describe those things that draw current thru the fuses (and they don't always list everything). The fuseblocks also function to distribute power elsewhere -- i.e., +12V power from the ignition switch comes into the top of fuse #2 via the A (light blue) wire and is bridged over to the top of fuse #1 by the fuseblock where it exits via the G (yellow) wire to run the ignition system (since none of this current passes thru the fuses themselves it is not included in the fuse description). Also, if this "bridge" connection between the tops of fuses #1 and #2 is bad, no +12V power will be supplied to the top of fuse #1 (fuse #1 runs the electrovalve controlling the airbox flap mechanism on US versions) so all those fuse #1 items will be dead. Adding the Pertronix modification probably increased the current required for the ignition system and helped "melt" your fuseblock quicker than usual
Answer is: The fuel pump. The fuel pump isn't run directly off the first two fuses but voltage at #1 and #2 does provide power to fuse #3, the fuel pump fuse and pinpoints the common reason why Birdman makes fuse blocks. Relaxed plastic at rivets of #1,2,3 cause high resistance, heating, and discoloration at #1,2,3 (top) Since you are a curious sort who demands answers, you should consider getting the diagrams for your car - see http://www.FerrariWiring.com. I referred to them for this post. Unnecessary facts relevant to the question - fuse #1 feeds wipers, turn signals, stop lights and several relays fuse #2 feeds gauges, reverse lights, seat belt warning, slow down __________________________ http://www.FerrariDiagrams.com
OK, since you claim the fuel pump isn't cutting out, let's examine the possibility of voltage loss or intermittent at fuse #1 perhaps killing voltage to a critical relay coil. Those include windows and radiator fan relays. Not critical. OK, Hazard lights and stop light. Not critical. Moving to fuse #2, voltage for oil temp gauge, speedometer sensor, two electrovalves, air relief and air intake closing. Emissions, not critical. Slow down circuits and warning lights, seat belt circuit. Not critical In fact you should be able to completely remove fuses #1 and #2 and have a running engine. In fact, try it. My vote is still with the fuel pump unless the airbox flap completely strangles the carbs...not having a carbed car I can't verify this. __________________________ http://www.FerrariDiagrams.com
That is true ONLY if the connection between the tops of fuse #1 and #2 is OK -- if it isn't OK, the ignition won't work.
I wonder if the car would start with the flap shut (ie choked off from all air?) in my case, its not even sputtering to start, its like there is no spark at all, and the top of 1 and 2 are brown and melted.
Can't say that I ever operated mine with the airbox flap intentionally closed, but my guess would be that it would at least try to "cough" into life. Some air would be drawn in thru the crankcase venting system and, if a vacuum did develop inside the airbox, it works to open the flap. Not sure that you need to look into it (since you've got Birdman's fuseblocks on the way), but, if you add some sort of "jumper" to electrically connect the top of fuse#2 to the top of fuse #1, you could see if it then starts.
Exactly. Coil voltage comes from ignition key through the bridged top of the fuseblock (at fuses 1,2,3). I'm eager to hear whether the air flap needs to be energized to allow air into the carbs. In which case the car should run with fuses #1 and #2 removed, assuming of course the bridge to the coils and fuel pump is sound. And that after all is where the discoloration is IIRC. Actually this is all mute since he's already bought the Birdman block but a curious hypothetical nevertheless. ________________________ http://www.FerrariWiring.com
there is a slight backorder on the fuseblocks, so i am going to try the jumper, then for fun try to start it with the flaps closed. I will report back
