HELP! 1984 308 Keeps Shutting Itself Off While Driving

(I posted this in Tech but thought that throwing it down here for more exposure couldn't hurt)

This happened to me once last summer on I-20 at speed and it spooked the hell out of me but it started right back up again on the side of the road. I was just outside of Atlanta on the way home and it made it back just fine. I honestly had forgotten about it - until yesterday and it returned with a vengeance. On a 70 mile drive with a local car club, the engine would just shut itself off. It was like you turned the key off. The electrical system was still working. The radio would still be on, the lights would work and the dash lights would operate , but the engine would just die and not start for a few seconds. I could get it to restart by pushing the clutch pedal in and letting it back out while I was on the move a few times. I was even able to restart it on the fly with the clutch in using the key again. It would restart and I just let the clutch back out and keep driving. A few other times I had to sit on the side of the road for no more than 10 seconds and it would start and run again.

A few things:

When it was running, it ran great. No misses, no power loss. Smooth and perfect.

When it shut down, it would just die. No backfire, no preliminary power loss, no hiccough whatsoever, just instantly off. Period. Absolutely no warning. Just off. Dash light all on, radio playing but engine off.

When it started again, it would start instantly and run perfectly. Just like it is supposed to as if there was no problem at all and it would pull away with full power again. Absolutely no hesitation to start and no rough or stumbling idle.

One thing I did notice and I don't know if this means anything but when the engine died, the tach would still be matching the engine revs (I would still be in gear at about 50 or 60 mph when it did it) In other words when the engine shut down the tach would still be where it was running and as the car slowed and it would gradually go down as the car slowed. I would have expected to see the tach fall to zero when the engine shut off but it didn't.

It seemed to like being above 4500 rpm. I was able to get where we were going by keeping the revs up high like that.

We have a tow truck follow us on our drives so I got it back home that way. Of course it started fine and I drove it up on the flatbed. As I was sitting there on the back of the truck idling, it died again. After the car was dropped off at my house, it started fine and I drove it back off the truck, down the driveway and in the garage without a problem.

Any ideas? Since the engine runs great (when it is running) I am relatively comfortable this isn't a "serious" problem. I am going to get it up to Ron in Atlanta but I wanted some Fchat input in the meantime.

 

When my fuel pump on the '83QV was on its way out, this would happen. So check the fuse contacts(maybe the circuit is overheating loosing contact?) and then the fuel pump.

 

I've had exactly this thing happen 2-3 times at faster speeds... say, 45-65mph on a highway. Scared the hell out of me too.

My research on it seems to indicate the problem is either 1) a short/bad connection from the ignition switch or b) bad mojo at the fusebox. I've replaced my fusebox with a modern version, so in my case I don't think that's it. So that leaves the ignition switch. Which makes sense, as it acts just like you physically turned the ignition off.

The suggested solution was visually check the wires and contacts of the ignition switch + application of contact cleaner. I haven't done anything yet myself, as it's very rare (so far) but it's on my short of list of "stuff to address." Maybe give that a shot and see how it goes.

 

Fuel pump. Have you changed out the fuse for a thermal breaker?

 

No. Should I ?

 

No, I did in the 400i, which had an annoying misfire, which felt electrical, I think is the breaker cutting out on one of the pumps, then cutting back in when it cools. With the single pump system on the QV, it would shut down the engine. Just a guess as to the mechanism. Maybe failing fuel pump relay? I think the current draw goes up when the pump begins to **** itself, so would blow the fuse in your case. Maybe wire up a tell-tale from the pump relay?

 

I am actually surprised I am not having a misfire of any sort.

It is as if a passenger is trying be be funny and keeps reaching over and turning off the key on a perfectly running car.

Just as if that were the case, it would simply turn off and I could start it up again beautifully and run tip top again a moment later.

 

Just adding this for extra info: When I replaced the fuse blocks, I also replaced all my original/metal relays with brand new Bosch ones, and I know the problem has occurred since that time. So while the problem might be a relay, it might also not be. The joy of Italian wiring.

 

Disconnect the battery.

Get a can of aerosol electrical contact cleaner, shove the nozzle deep into the ignition key slot, and blast away.

Then work the key in, turning back and forth repeatedly.

Repeat the above, over and over again, until the cleaner pours out clear.

 

Don't know if this is helpful or not, but I had an '82 Alfa Spider with the exact same symptoms. Turns out Alfa recalled them for ignition switch replacements. Given parts interchangeability, I wonder if the same switch was used in 308s...

 

I actually have an 82 Alfa Spider (owned it for 21 years last month) and I'm WELL aware of that issue. The thing about that was the car would just not start. Turn the key and nothing would happen which I somehow simply got used to for two decades until this past summer when I finally went in and fixed that (hopefully) for good. Interesting thing, Alfa didn't relay the starter switch. Just installing a relay may have been the cure I needed going back 20 years

 

While the engine is idling, try to wiggle the key and see if the engine shuts off, if it does, the switch is your problem or the connection to it.

 

My 308 Euro was doing this to the PO of 20 years when he took it in for service but they could not find the issue despite much effort. So PO gave up and I drove it only to have it do the same thing. As I sat in the car waiting for the wrecker, I realized there was no power anyplace. Reasoning this meant an issue between the battery and the car I realized what must be the problem. Bought the car took it home, replaced the battery in the key fob for the aftermarket alarm system and turned off the theft protection.

 

Tommy:
I think most likely culprit is going to be either a cracked connector behind the fuse box or perhaps a worn relay / fuse connection. check your protection relay in the back trunk - right side ... the fuse could be cracked etc... but my guess is that either the connectors behind the fuse block or down in the passengers foot well, are getting hot - cracked or both. eventually it will just stop the car. Expanded metal, when it gets hot combined with vibration breaks the connections. - power to fuel pump goes out. - the pumps pull a lot of amps... and in the QV's they are under fused / protected.

worst case would be the fuse box is becoming delaminated along the fuel pump / ignition circuits... Ron will get it sorted. ( if you are looking for the connectors you have to un screw the fuse holder - and pull it down, and look at the large white connectors - you can quickly tell when you un plug them - any brown burn areas are the culprit. - you can dis connect the two wires and put in an inline fuse to get you back on the road. the foot well is a PITA on the back!

 

Posted in other thread as well, sounds like the ignition switch. I'd also check the batt voltage at idle and 2k rpm. A bad or arcing switch causes all kinds of goofy problems. The shared switch unit is to a BMW, 2002tii as I recall, unfortunately those are also really expensive. I think they caught on to the prancing horse cross over

 

Thinking through the symptoms, I would think a fuel pump problem would give a little sputter before cutting off. If I understand correctly it is off as if the ignition switch were switched off. Sounds like ignition to me. Mine's a euro and I don't have a book in front of me, US QVs are still two distributors and ignition boxes right? That kind of rules out a worn cap or faulty wire or coil since you would only loose one bank. The other catch is the tach stays on and continues to report RPM. If I recall, it reads RPM from a third pickup. That makes me think not the ignition switch, but wiring between the switch and the ignition boxes. The Marelli test output is in the wiring diagram, you may be able to test for power there, or hook up a multimeter while running to monitor.

 

You're describing a 328 fuse box - his is a QV

 

You are right - sorry about that, forgot different fuse panel. But I think the connectors are virtually the same in the footwell and behind the fuse panel..? I think the protection relay is in the foot well on the Qv's.... the fuse panel lifts off the pegs on the dash...

 

I have a 84 mondial QV
I had exactly the same problem : at the beginning, engine stop without any default.
After one night, the car run perfectly? But a few days later...
My Ferrari specialist think of bad connection on the box of fuses and relay.
As it's part of my job, I've repair and test the box: perfect
So, I was sure to have repair my car : not at all!
Finally, we have found a wire who have a bad contact : it was a thin yellow wire, for the +12 for the power of bosh electronics blocs for ignition.
This problem is probably happen because of the steering wheel adjustment: this thin cable run just above.
I have replace this wire: it's OK now
PS: excuse my poor English, I'm french
Wish you the best for your repair
Michel

 

Check and clean ground straps too. Could be that simple.

 

check the rotor arm in the distributer, I had the same problem, engine would just stop as if it had been switched off but everything else worked, on close inspection the rotor arm had a crack in it which caused an intermittent fault and no spark to the plugs while driving along hence complete and sudden engine shut down. Replaced the rotor arm and the problem has never come back since.

 

Please excuse my ignorance of the 308 series, but does it use a CDI unit (I think too old for an ECU)? On older Porsche's the Bosch CDI would cause strange issues like this due to cracked traces or failing (old) electrical parts and there are people that rebuild them better than new. Just a though, wish you the best finding a solution to an annoying issue!

 

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I don't get this part at all. If the ignition switch, or anything electrical, was killing the ignition the tach should die.
Doesn't that point towards a fuel problem?

 

Not necessarily, the ignition switch has a run position that does not cycle out till the key is fully rotated back off, so it can momentarily short internally and kill the ECU relay but remain powered. Unlike some other switches where if you tried to start the engine you simply cranked again by turning the key, the switch Ferrari and BMW used requires the key be fully cycled back before attempting again, makes hard starting a real PITA with the constant cycling of the key, esp when updating to a modern ECU the uses key on power and having to cycle off to restart resets the power to the ECU.

There's also a possibility of back feed if the instrument cluster shunt diode has gone bad or was toasted from a voltage spike due to a failed regulator. But that's a rare one.