Intermittent dead electrical system 1991 Mondial T Coupe

OMG, almost exact experience i just had a few weeks ago. Stops dead, no gauges, then restarts and runs without a problem for a few miles, then repeat....dead stop, etc etc.
Prior to that, no AC -- possibly the harbinger.

Pull the connectors on the fuse panel and i bet you find a browned burned terminal.
See my post earlier this month, with pix of the burned melted terminal.
I ordered a new improved fuse panel from Guido (under Red Bay Cars) on this forum. Waiting for it to arrive.
Costs about $990 shipped (750euros + shipping), but GTCP costs $1200+ and you have to send in your old one, and Scuderia (?i think that's who) is $1800+.
Guido does the actual work making the boards and also owns a Mondi.

Let us know what you find.

 

BTW, like your experience, we were just finishing up a drive from Portland OR, down the west coast and across to Houston (about 2400 miles). Happened just outside Ft Worth TX.

 

Here's a link to my FC post about this problem: https://www.ferrarichat.com/forum/threads/84-qv-quits-gauges-stop-wait-5-min-then-restarts-no-problems.647884/

I understand about the continual money-pit-and-no-enjoyment. This has been the saga of my life, and I am SERIOUSLY CONSIDERING buying a brand new, showroom-floor, RELIABLE and cheap car that will start every day without a fuss, and run forever.

 

Mine starts every time, runs reliably, for the last 135'000 mls... I fitted Guido's excellent electric board years ago. It's a lot of work to fit but fantastic quality. The GT Car Parts board is plug and play and seems of very high quality as well. Ferraris don't just quit by design - there is obviously a problem somewhere that needs to be fixed.

 

Well, there's a ray of hope. Have about 95K miles to go -- OR, should I expect after this fuse panel/electrical fix, I can start the clock for 135K miles of carefree driving?

 

Very similar problems a few months ago. The entire air system shut down. Was a few crimped wires at the fuse box. Usually from someone forcing the cover back on. It is a pain with the spare tire in the way and a tight fit.
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Of course! Well... It depends on the state of the rest of your car. What I found by far the 3 most serious issues of unreliability are 1) deferred maintenance 2) "improvements/upgrades" 3) bad repairs. This is closely followed by cars not being driven/sitting too long.
All I can say that mine is reliable enough to be a daily driver, even in the challenging climate here in HK. So I don't see why anyone else's couldn't be.

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PS: Usually 300mls on a tank before the light comes on.

 

The difference of Guido's solution compared to the alternatives is in its basic construction - he is hard-wiring everything with copper wire, and using substantially larger connector pins. So his basic board and connectors are rock-solid.
But it means you have to cut and re-crimp every wire and increase the size of the slots in the plastic connectors so you can fit everything back together.
The other products replace the original board with what I believe is a much higher quality but otherwise similar PCB solution keeping the original pin size - so plug and play.

 

When your car doesn't start are the door lights working? If so, could it be an issue with the ignition key unit?

 

The $1100-1200 I spent on the GT fuse box was the best money I have spent on my car. So many issues just ceased to exist after replacement.

 

Hate to say this, but your car might be on its way to more permanent failure. Our car exhibited small seemingly unrelated and intermittent problems: 1) AC compressor stopped clicking on; 2) gauges would intermittently pop down to zero for a microsecond while driving, then come back up without the engine missing a beat.
I do not know what you could check, but i'd start with the pulling the side connectors and checking for melted wires -- just in case. Otherwise, I guess you might as well just drive it until something happens, huh.

 

Curious about this! While many electrical things failed on the car when the engine and gauges quit, BUT THE HEADLIGHTS STAYED ON, AS DID THE DOOR LIGHTS WHEN I OPENED THE DOOR!
Can you elaborate on the ignition key problem? Maybe I should preventively address the IGN switch while the car is down?

I hate where this is going! It's truly a rabbit hole that may be unending.
The greatest fear is that this car will be ANOTHER SIDELINED PROJECT that never gets completed, and ends up getting dumped after a couple years of sitting! No kidding. In fact, I have been the beneficiary of other people's similar sidelined projects, where they just gave up on fixing a car that ended up sitting for a few years, awaiting the time and energy to finish the last 100yards of repairs.

 

Some circuits like door locks, interior/courtesy/hazard/headlights/radio memory/horn etc are permanently under power.
All other circuits only get connected to the battery when you rotate the ignition key to the running position - dash lights/instruments/ignition/all engine systems etc only come on at that point.

So if your car won't start but the permanent circuits are all functional - it could be an electrical/mechanical issue with the ignition key unit itself preventing those circuits from powering up.

Don't give up. Find the problem and fix it. I would look at the ignition problem for sure.
I noticed on mine that when you try to fold the folding key part it interferes with the knee protection on the column shroud and it will cut the ignition because it rotates back a touch - mind you, it's RHD QV, not a LHD t. Just saying.

 

Did you check the battery kill switch and make sure it’s fully turned open?


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So the car has no power - the clock will reset to 00:00?

First thing I would do is bypass the battery cut-off switch on the negative side of the battery. A disconnected battery ground would certainly shut it all down efficiently.

A loose positive side wouldn't help either. Just check. There are 2 fat wires running from the positive terminal across the front bulkhead to the fusebox. Check their connection on the battery and on the fusebox left upper side.

And yeah - a new fusebox won't hurt your long-term expectations of reliability! It's worth the money which ever you buy.

Looking at the diagrams - at the moment, I can' see how there could be any rational connection to the non-starting issue - other than through a burned out PCB or connector with the HVAC main supply being affected by coincidence.

I'd look at the AC issue separately; the entire system is powered by 1 wire coming via a relay and fuse from the fusebox.

 

Welcome to the club ! We...all mondial owners did have those troubles in the past years. I did to. First thing I did was making a new fuseboard. Then connecting all massa points in the car to 1 big wire of 4 mm2 and that connected directly to the negative of the battery.
So once in a while the car would not start...renewed the starter, starter solenoid, by passed the starter relais with a bosch relais and start push switch.
And still the car did have his tricks...not always starting. The last thing that resolved my problem was changing a coil. Apparently there was current escaping and there was not enough over to start the car.
I would start with a new fuseboard. Then a NEW cut-off switch on battery. After this you have to find out other errors of bad contacts, one after one other.
Good luck and dont give up. Those are great cars but its a full time job to keep them on the road.
Guido

 

... mine handles quite ok....

 

I also put in Guido's fuse box about a year ago.

I had the SR upgrade for a few years, which is a clever design. It separates the fuse box into two separate fuse boxes; regular and auxiliary. It spreads the load over more circuits. As good as it is (and Dave is as knowledgeable as anyone in taking care of these cars), the fact you are starting with an old fuse box design is the weak link. Guido's fusebox does take some time to rewire and once you start you are committed!! But it has taken care of the electrical gremlins that are the hallmark of our cars.

I would also suspect the ignition key switch. Get the Bosch WR1 relay kit (from memory) which takes the load off of the wiring for the starter motor. Here are the instructions: 106122 Bosch WR1 Low Voltage Relay Kit Installation Instructions (mamotorworksmedia.com)

Last time I checked it was on the order of $30. Very cheap investment. I hid the relay and fuse on the back panel where the Motronic computers are.

Regards,
Jerry