This one has me puzzled. My car runs absolutely great most of the time. Has good drivability around town in stop and go traffic. Is a freakin blast in 3rd gear at 4500 – 5000 RPM though the twistys. It normally runs just like it should in any gear at any RPM. But... it has developed this nasty habit of cutting out at random times. It first occurred back in July when I was driving to the Porsches to Oxford event. I left my house and had been driving along for around 25 minutes, I was cruising along at about 50 miles an hour and it cut out and sounded like it was running on 1 or 2 cylinders. I pulled into a lot and feathered the throttle. It sputtered for 5 seconds or so and then started running fine, just like it should run. I shut the car off and it started right back up like nothing had happened. I got back on the road to Oxford. About one and a half hours later it did it again. This time I was driving around at about 30 mph. It sputtered, kept running poorly for about 5 seconds (again sounding like it was running on 1 or 2 cylinders). I feathered the throttle a few times and it came right out of it and started running fine.

This type of cutting out is still randomly occurring. It will sputter for 5 seconds or so and then come out of it. Or, sometimes the feathering of the throttle will not bring it out of the sputtering and it will die or I will shut it off. It will usually start back up after cranking on the starter for 6-8 seconds (That kind of cranking that seems like winding the car up and eventually it builds up enough desire that it starts.) Usually it starts up and sounds like its running on 1-2 cylinders. After this type of “wind it up” starting 2 or 3 times, it will start up and be running just fine. Then back on the road....

I haven’t been able to determine any pattern other than it will continue to happen until I fix something.

The details of what I am working with: 2056 built by Jake some years back, dual Weber 40’s, Mallory Uni-Lite distributor, Facet Fuel pump, MSD 6AL.

Here’s what I’ve done so far: replaced the fuel filter, installed new facet fuel pump, installed new Aurora plug wires ( I had them and thought maybe it would help), sync’d the carbs. I bought carb rebuild kits but haven’t rebuilt the carbs yet. Thought I’d check with you all for other ideas before I rebuilt the carbs.

Any ideas on what could be causing the cutting out?

Oh yea, one more thing that occurred 2 times tonight while test driving. The car backfired out of the exhaust 3-4 times in rapid succession in about a second or two. Then the car ran just fine after that.

I sure could use some help on this one. I can’t drive it like this to the Rocket City Ramble.

Head temp sensor? My B-inlaw had a some what simular problem like you. We just happen to be at Brad Mayuers shop and he swapped in a new head temp sensor and we were good to go.

YMMV

sounds like an intermitint elec short.

These can be real tough to find.

start the engine and jiggle all the wires in the engine bay and see if you can get it to repeat.

I had close to the same prob one time. It tuned out the throttle cable shorted out against the ignition coil spade connector. The current flowed all the way to the ignition switch and fried the the switch

It could be a wiring/grounding issue. But just to be on the safe side, I'd rule out mechanical first- mostly because this is the easier of the two to deal with.

You've taken good steps so far with what you've done mechanically, but try running fuel system cleaner through it- it's possible that the carbs and/or intakes are gummed up and causing things to stick. Also replace the plugs.

And you might want to also check to see that your valves are not out of adjustment.

Replace the coil

Great input so far guys. I'll try some of these suggestions. I have a spare coil or 2 around so that should be an easy trial. I have just adjusted the valves. Must have got them adjusted better this time the engine is much quieter than last time.

I hadn't really thought much about an electrical issue, other than possibly the MSD maybe acting up. Probably because I dislike electrical issues so much....

I'll try a few of these suggestions in the morning/afternoon.

Keep the help coming, I need to fix this Sunday if at all possible.

Fuel. If it started happening suddenly, I would think water in the fuel, I would check the distributor and see if there is moisture inside. Just a suggestion and doesn't take but a couple of minutes to check.
Hope you find the cure fast since RCR is less than a week away.

Mike Cooley

It is widely if not well-known that I dislike the MSD-6 for exactly this reason. I fought this problem for a year before finally replacing the "surely it can't be that' (and most expensive) part.

If you don't have the high-vibration Blaster-2 pulse transformer ("coil") it couldn't hurt to throw one of those at the problem. But having a known-good real coil and condenser available as a backup could be a good thing to have in your spares kit.

Doug,

Just bring it to the RCR. Or just come to Memphis on Wed/Thu and caravan in with us. I am really good at tracking down electrical problems, and I am bringing my LM-1 and my scopemeter, so we have everything we need to troubleshoot it.

But in my opinion, it sounds like an ignition related problem Carbs either work or they don't, there is really no halfway. Put standard points and a standard coil on it and see if it helps.

The only other thing would be a fuel line blocked. That would drop both cylinders fed from the one carb.

I swapped out the coil. It did have a Pertronix Flame Thrower coil. The short epoxy filled one that is vibration resistant. It now has a Bosch Blue coil.

I went for a drive and it started acting up after about 14 miles. Loss of power/sputtering for 1- 2 seconds while cruising along at 50 mph.Then started running just fine again. It does seem to be a bit less responsive at around 2700 - 3500 RPM with the Bosch Coil. Seems to sort of sputter a little until reaching about 4000 RPM. Also had the rapid succession of 3-4 backfires out the exhaust while cruising at about 45. Then started running fine again. And one more backfire session after slowing down to turn onto another road and pull up a hill. Backfires, no power for 1-2 seconds (One of those oh-shit moments, in the middle of a hill car dying out of course with a car right behind me.) and then running fine again.

I also pulled the distributor cap and all looked well and dry. No water should be present in the fuel. I ran it out of gas yesterday while running in the garage. So it now has fresh fuel.

I jiggled the wires around a bit and can make the coil jump spark from the center tower wire to the positive terminal. Didn't seem to make the car run any different just jump spark. I can improve the connection here to prevent the spark jump.

One more thing that I did yesterday was change the main jets from 130 to 125. Trying to get the car to run not so rich.

I am now considering bypassing the MSD. And then if necessary the carb rebuild is next on the list.

Any more ideas?

MSD disconnected and went for a test drive. Drove for 45 fun filled miles with no signs of that silliness of the car cutting out!!!

Maybe that's the solution -no more MSD.

I am going to change the main jets back to the 130's. The 125's seem to be ok, but the 130's seem to have fewer minor transition stumbles coming off of the idle circuits. Plus they seemed to provide better seat of the pants feel in the 3400 - 4000 RPM range.

I'll drive another 45-50 miles tonight going to dinner. That will give me a good feel for the 130'scompared to the 125's.

Feeling MUCH better about driving to the Ramble on Thursday.

Thanks for the help guys!!!

I just went through a similar experience wqith my 2056/Weber car. It started cutting out on the freeway, at around 70. I suspected the filters, so after changing both the under tank and rear fuel filters, it ran better for a day, but then started cutting out in town. Turned out it was the fuel pump safety switch (Holley 12-810) becoming intermittent after 6 years. Ordered a new one and all is well now...

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Great News!!!


So... does this mean that you are going to meet up with us in Memphis on Thursday?

Changed back to the 130 main jets and drove to dinner and back. Another 45 miles with no issues The car seems to be running just as it did before the cutting out shenanigans started. Running strong and bringing on the smiles....

Now I get to try to get all of the clean up and detail work done to get ready for the Ramble.

Clay - It would be great to join up with the caravan, but memphis would be alot of additional traveling for me. I am planning on heading down I65 into Huntsville. We'll all meet up there and have a great time!

I went through 2 MSD units before deciding it wasn't worth the trouble.

Look forward to seeing you at the Ramble.

I didn't know your route, so I was just offering.... safety in numbers and all that!


See you there!!!