MY 308 DIES....LONG POST

The car in question is my 1976 European 308 GTB. About eight or nine months ago the car got new plugs, new points, rotor, cap, and the distributor was set up professionally with a distributor machine. At that time, I cleaned the top half of the carburetors, including a thorough cleaning of the accelerator pumps, idle jets, checking the floats and verifying that I got a good pump shot from all 4, when I hit the throttle. Timing set @9° BTDC.

The car has been a pleasure to drive until about the last two or three outings (6 weeks). It starts great, it idles great at 1000, accelerates well. No issues or problems. However, after about 40 minutes of driving, some of it modestly hard, the car dies when you try to accelerate, even gently, from a stop. This occurs under very nice ambient temperature conditions, say 70° or so. It usually restarts on the second or third turn of the key and then will run fine until you have to stop again. Rinse and repeat.

More details: There is no warning that it will fail to pull away from a stoplight. It just dies. It doesn't stumble or stall, it just dies when you touch the throttle. When you arrive at the stop sign, it idles perfectly. It's only when you try to pull away from a dead stop or back up. Once it starts to pull this stunt, it will do so until you park it. I've not tried to see if a 20 minute rest (? cool off) makes any difference because I've been so glad to get home that I didn't care to chance a repeat again!

What's been done?: thinking that it was in the accelerator pump system, I checked, and had a professional mechanic verify, that the accelerator pumps are working great, as they were before.

Next, we moved on to timing and with the digital timing light, at a steady 1000 RPMs, the timing mark jumped all over the place. (I just borrowed an old style dial back Craftsman timing light, which I have yet to try.) Despite the erratic timing light values and tach readings on it, the car idled perfectly, without fault at 1000. From there, we gently accelerated all the way to 5200 RPMs. It reached 33° at about 3500-4000 RPM and stayed there steadily until 5200, when we stopped. At no point did the engine stumble, stall or miss. The digital timing light, which had been erratic at idle now read steadily at 33°.

The fact that the car completely dies without warning or stumbling leads me away from a fuel problem. Some early suggestions as to what to do next include checking the fuse, checking the relay marked ignition, (marked Bosch 872), and the ignition switch.

I know this read has been long and arduous, but I wanted to try to get all the facts out. Thanks for your thoughts. steve

 

My oft-used Ferrari mechanic, Terry Myr in Michigan, suggested that the problem with the timing light was indeed cross talk and unrelated to the current situation. It's also his idea to check the fuse box which I plan to do this morning. He doubted that the relay was involve.I have a "Birdman Fuse Box" upgrade. More later thanks again, Steve
Steve

 

Thanks guys! I've got my marching orders. s

 

Thanks, Andy (Tuttebenne) for the suggestion. As I understand it, it would be difficult to execute in this acute and fleeting problem. It would be cool is if you had a video of that test light at the instant the problem occurred. If we don't find anything obvious in the ignition wiring or fuse block that would be next it seems to me.

Detroiter, you brought up an interesting point. My condensers are allegedly NOS, installed when the distributor was rebuilt about 9 or 10 months ago? Is there anything within the distributor itself that could cause an immediate and catastrophic failure like this?. Correct me if I'm wrong, but both of those would have to fail simultaneously for this to occur. Right? Otherwise, if one of them was still working, the car would run terrible but it would still run; in my case it just dies..

I am no longer flexible enough to crawl around under the dash like I did forever ago. But, I did take the fuse cover off and everything looks great. no blown fuses no corrosion, no suggestion or hint of a difficulty. yes, it's possible that Birdman fuse box could be at fault here, but it seems more likely that it would be upstream.Yes, it's possible that a Birdman fuse block could be at fault here, but it seems more likely that it would be upstream. Here's hoping when I get someone to crawl under there and look at the wiring as much as possible we'll find the culprit.

Thanks again, Steve.

 

@ChevyDave thanks so much for your interest. As far as I know, if I drove the car for two hours without stopping, it would be fine. I've not done that, but I've had no problems as long as the car was not completely stopped. It does not stall or stutter or run poorly. When you pull up to stop, it idles nicely and everything seems fine and then you go to pull away, and it cannot take the throttle, even if gentle. On the second or third attempt, it will restart after about 20-30 seconds, but if you don't keep the idle up you can't move away because it dies again. It certainly seems bizarre to me; I'm trying to give as accurate a picture as possible. One thing that I've noticed in this discussion is that when I'm in this circumstance or where there's traffic all around, my anxiety goes up and my ability to remember important issues goes down. This is my disclaimer for failing to know all of the questions that need to be answered. thanks steve

 

OK, today a professional mechanic went over the car with me. We found nothing whatsoever in the fuse panel, relays, coil wiring, etc. Everything seemed to be in order, with no evidence of burned wires or overheated connections. However, while we were fooling around with this, the car acted like it had a dead battery, which would be extremely unlikely because the battery is only 18 months old, has a new voltage regulator only 12 months old, and is kept on a trickle charger all the time. Upon further inspection, it was clearly noted that the battery cut off switch on the negative post was loose! Of course we don't know with certainty that that's the problem, but it certainly is not a good thing. So, when the weather improves,which I hope to be in the next few days,, I will try it out and report back. It would be just too fortunate if that was the diagnosis! Thanks, Steve

 

@I must admit that I also considered vapor lock or some sort of percolating issue. The reason that I strayed from that theory, was that it wasn't that hot outside.... the car had been run in much hotter ambient temperatures, for 2 years now., And, the car just acutely died: not stumbled, which I would've expected with a percolating fuel. I don't know if ETOH based fuel or non-ethanol fuel has a higher boiling point. The car had non ethanol fuel in it as I recall, and had run flawlessly for 40 minutes or so, before the acute death. At any rate, that was my thinking.

Best steve

 

I have heard of such problems. When I hear that, I always wonder if it's a bad voltage regulator. At any rate, with the cut off switch snugged up, the car fired up immediately. So, I don't think it was the battery per se, but the connection thanks, Steve.

 

Not measured though I suspect it's correct around 4 to 5 PSI. As previously noted, good accelerator pump shots all around every time. s