TC fuel flow problem, or what?

[Fotog]

I was driving the TC with mechanical fuel pump about a week ago and it started to run out of power and finally stalled-out altogether.  One of those things where the further you opened the throttle, the worse it ran.  Missing, etc.  I'm trying to figure out what happened.

I was admittedly low on fuel.  I wasn't going so far, and the gauge read between 1/4 and empty.  I don't recall running it that low before, but I dipped it and there was about 3 inches in the tanks before I left the house.  I had driven about 10 or 12 miles and was going up a hill when this occurred.  I drifted to a stop on a side street.  Turned the key, and it started and stopped in a few seconds.

I was able to check for a spark, and that was good.  I re-checked the tank and had about 2 inches of fuel in the tanks.  I thought that should be enough, but I don't really know where the outlet pipe is relative to the bottom, so had my wife bring me some gas.  I didn't want to be too dumb about this.  After filling, I had her crank it and could see fuel flow.  It took about a minute before apparently the carbs were filled and it started.  It sounded and ran fine; powerful, etc. 

I drove it 1/4 mile, and the same thing happened.  It died.  After sitting for a couple of minutes, it started up again.  Sounded and seemed fine.  I drove it a few hundred yards, and the same thing.  Poor running, low power, and ultimately stall.

I did this to get the car about 3 of the 7 miles to home, and finally had it towed the last 4 miles.  The last time, after sitting a couple of minutes even, it didn't start.

I'm not sure what to make of this and how to troubleshoot it.  It sure seems to be fuel flow related.  I could easily replace the fuel pump which I don't mind doing, but I prefer to understand the symptoms and what could be happening if generally it benefitted from sitting for a few minutes.  If fuel is somehow not getting to the carburetors, then I would expect that some significant cranking would be involved before it would start again, but that wasn't the case, at least until I gave up and had it towed.

Any ideas, especially about how to diagnose this, will be appreciated!

Vince

[Pfreen]

The symptoms seem like it is the coil.  It would be difficult for a fuel pump issue to cause what you described.  You have two carbs so the float valve is redundant.

[Fotog]

Interesting.   Given that the coil is basically a transformer, I would have expected it to either work or not, and the failure mode to be shorting internally after insulation breaks down.

Thanks!

[Clifton]

If way to lean, you will get the lean backfire through the carb at WOT.  How is your tank internally? originally I thought mine was good enough until it plugged my pre pump filter to the point it would only idle.  Not saying it's fuel but.

I know ignitions have issues when hot, cool down then work, get hot and don't

[Fotog]

Thanks, fellows.  I'm not lean, pretty darned sure.  No backfiring through carburetors.  Not long ago I went to hotter plugs: NGK BP6ES vs BP7ES as they were fouling, a little wet too.  I've only looked at one since, but it had a lot of carbon; no wetness. My Strombergs aren't adjustable.  After some other todo's, I thought I should look into that, as maybe too rich.  Seems like a lot of somewhat volatile PCs from the exhaust when running.  I don't know if it's oil that gets through the valves or rich A/F ratio affecting the plugs.  I think the tanks are fine, but I don't really know in detail.  Another thing to investigate.

I just checked resistance of the coil though.  I was lacking knowledge until now.  Primary seems fine at 3.3 ohms, but the secondary is low at 8.6K ohms.  Getting a new one on order now.  I think Paul is right!  I appreciate the response.

Vince

[Pfreen]

A coil can fail intermittently.  I always carry a spare.  It's funny how I learned this.  When I was 14, my father had a 1966 Shelby gt350h.  (The one that is black with gold stripes)  It was doing something similar to yours.  I went with my father to the Ford dealer .  They changed the coil and the problem was fixed.  I am not saying that is the problem.  But, it will eliminate one variable.

[jbcollier]

Diagnosis is a methodical process where you test each potential problem area carefully until you find the issue.

Make sure the issue is still present.  Then disconnect the fuel line to the carbs and point it into a plastic bucket/container.  Crank the engine for 10 seconds.  How is the fuel flow?  (There will be a spec in the manual on fuel/time)  Any crap in the fuel?

If it all checks out fine. Then look at your ignition.  There can be a problem and still show a fat spark when cranking.  Condensor issues can feel an awful lot like a fuel issue.

[Fotog]

When I was 14, my father had a 1966 Shelby gt350h.  (The one that is black with gold stripes)  It was doing something similar to yours.  I went with my father to the Ford dealer .  They changed the coil and the problem was fixed.  I am not saying that is the problem.  But, it will eliminate one variable.

 
I would have been 10, but we should have had one of those.  We lived outside of Detroit then and dad worked in marketing for Ford.  We got some new car every year, and had a series of Mustangs, but never one like that.  Dad wasn't really a car enthusiast, not yet 40, with 4 kids... 

John-  Thanks for the suggestions.  I'll try to be as logical as I can about this.

Vince

[wilkrod]

My car had the same symptom when I purchased it, turned our the outlet of the fuel tanks were pluged with crud.
Easy enough to check.
Regards

[4129R]

Change the coil for a 12v gold top coil. If that doesn't work, change the points and capacitor. If that doesn't work spray quick start into the carbs. If that works, you have a fuel feed problem.

Start with the most obvious and simple to fix, and then work through the list.

I went through the whole list, used a different type of quick start, it started first time, and starts easily thereafter, so I have no idea what the problem was. Fuel feed?

[Bainford]

If you replace the condenser, get one from Distributor Doctor. The Lucas branded ones currently available are junk. A few years ago I had an ignition issue that was hard to cure. I replaced the condenser twice with no improvement, until I heard about the ones being sold by Distributor Dr. I fit one theirs and the problem was cured.

[Fotog]

Thanks for all the suggestions.  I drove the car the other day for about 10 minutes on nearby roads to confirm that the problem is still present, as JB suggested, but it was fine.  The two differences from my previous experience were that I hadn't just recently (apparently) run out of fuel, and the the ambient temperature was cooler by 5-8 degrees F.  It was in the low 90's when I had the problem.

I've been otherwise occupied generally since, but maybe tomorrow, a hot day, I will try again to duplicate the problem.  I do now have a new premium coil, but haven't installed it yet.

[Blitzen]

Could it have been vapor lock?

[Fotog]

I wondered that myself, but I haven't heard reports of that generally with Stromberg carburetors.... that I can remember.  I don't think I have any experience with vapor lock, so I don't know if it's possible that it can temporarily resolve itself, like the symptoms I experienced.  I've also probably driven in weather that hot before without a problem.

When I can get back to it I'll try to do some more investigating and see if I can find anything.

[RacerX]

This sounds very familiar. My car was in long term storage and after some reconditioning I was able to drive around the neighbrhood. I then attended a club even that was 10 miles away and on the way back it started stumbling. I was low on fuel and assumed that was it, but no. I could get a couple blocks and it would starve again. I found the fuel line from the tanks to the fuel pump was slightly blocked with sludge. I cleaned it out and blew back until I could hear bubbles in the tanks. Been fine for the last couple weeks. I plan on a more through tank clean and fuel line replacement over the winter. Hope this helps.
Mark