Engine cuts out

L

Loyd Nix

Senior Member
Flapper has been running like a dream lately with the exception of occasionally cutting out momentarily (a few seconds) and then catching again. I don't think it is the carburator as I had it rebuilt by a local pro and he fixed the idling problem that I had. Today I drained the fuel out and removed the shut off valve expecting to find rust scale in the bottom of the tank and perhaps fouling the valve itself but it was pretty clean. She has been doing the cut out thing off and on for some time but this past weekend I had to pull over twice to let her catch her breath while I kicked the tires and cussed her out. I finally got her home but now I am afraid to take her out again without some sort of remedy. Is it possible that the fuel tank is not being vented and a vacuum occurs to prevent fuel from flowing?
Just looking for thoughts on the matter.
 
The fuel cap should be vented and you should be able to see the vent holes, if I remember correctly there are 2.. Just see that they are free and clear.. A easy way to check for that problem is crack the cap loose and give her a run.. Another problem could be the fuel line entering the carburetor, See that there isn't too much line extended beyond the compression fitting [about 1/8"]..
 
Check wiring under distributor plate for a short or ignition switch if after market and not a popout type? or loose connection in ignition system. If you think its fuel loosen cap and drive. Keep us posted.
 
Lets compare this to the old adage about being thrown from a horse. You better get right back out there. This time when you leave, be prepared by having a small tool kit with you consisting of a wrench to remove the fuel line and a test light. The next time it "cuts out" then pull over and immediately check for ignition spark by removing the coil wire and spinning the engine over. If it has spark, then check for fuel by removing the line going to the carburetor. Having a spare coil and condensor will likely allow you to at least get back home, but until you do some diagnosis and troubleshooting, you will never have any confidence to go anywhere. Only after you realize that you have the capability to repair it will you have confidence in taking it anywhere again.
 
If the car has set a while (2 months or more) over the winter with gas in it, you could have a problem with the fuel. Try either new gas or adding some Marvel Mystery Oil. The stuff they're selling now that they call "gas" ain't what it used to be.
 
My coupe did that for years - almost like I shut the ignition off, then quickly turned it on again. I replaced the stranded wire under the top distributor plate with a "wireless pigtail" and haven't had the problem since. Like Gary said, you should at least check it out - one frayed strand touching ground when it feels like it could be your problem. $0.02.
 
I have driven my car enough to have this happen , First time it was the gas cap too tight and a topped off tank . Second time it was a bad condenser which finally failed . third time it was a bad ampmeter.Fourth time the coil which would give a spark when the points were opened by hand but not when cranking . Last time was when ******** the condenser came unsoldered ( I had just put it on a few days earlyer ) . I managed to make it home on my own power each time . Do as Brent says , drive it till you have the problem and start checking immediately. Easy way to check if amp meter has a intermittant open curcit is to jump a wire across the junction box terminals and drive it and see if it cuts out after a while . Bubby Sharp in KY
 
It really sounds like an electrical problem to me. Every single connection, starting from the battery terminals, is a possible culprit. This includes not just connections that are supposed to be there, but also connections that aren't--like cracks or tracks in the distributor body and other shorts. But, in my experience, most of the time this problem has been due to a bad ignition switch--try jiggling the key to either create or fix the problem. IF that seems to be it, a short term work around is to simply tape the two ignition switch leads together, or install a toggle switch, and pull the fuse or use some other quasi convenient shut off.

Steve
 
If moving the spark lever makes it miss then the wire under breaker plate is grounding to housing.Many times the wire was replaced with standard automotive wire which is too stiff.You should use very fine stranded silicone covered wire that you should be able to pick up at a hobby shop.I would rather fix it this way rather than use the wireless plate.But of course,this may not be your problem.
 
I had a problem like this, it was the metal ******** the points shorting out to the case of the distributor. Took a long time to find, and about 5 seconds to fix!!
Good luck!
 
I have checked all 3 "filters" and am waiting for an in tank screen filter from Bratton's. I am running a Zipper ignition so it is not points or condenser but I will look for a loose or exposed wire. I took the leather gasket out of the gas cap and the two holes looked clear although the gasket was jammed very tightly in there. Perhaps it was so tight it restricted air flow. When I get the screen/filter from Bratton's installed I will give her a try. I am leaning toward the vent problem but will keep you posted.
Thanks guys.
 
had an almost identical issue with a NU-Rex ignition that the previous owner put in my car. turned out to be the control module failing.
 
Loyd Nix said:
Flapper has been running like a dream lately with the exception of occasionally cutting out momentarily (a few seconds) and then catching again. ... .
Click to expand...

I'm curious whether this sounds like fuel restriction to anyone else; it really doesn't to me. Fuel restriction would not be momentary and instantly "catching again". Electrical cut out would.

If the gas tank vent is blocked, it will reliably take about the same time for the problem to appear after each start up. I would expect the dying to preceded by a bit of sputtering and maybe backfiring as the fuel level in the carb bowl drops and the mixture leans out. Then, it will take about the same recovery time period each time for air to leak back in so flow can resume.

By contrast, a break or short in the ignition circuit will cut the power instantly, and reversal can be instantaneous.

You've received several good suggestions. I'll add two more: My most recent experience with this phenomenon was with my mom's 30 coupe. It turned out the problem was a loose battery clamp, even though the guy who installed the battery swore that he had really tightened them well. Also, my understanding is that most electronic ignition issues arise from inadequate grounding. Whereever you've grounded yours may be just fine at that connection but there may a problem further along. Install an extra grounding strap from the battery to the transmission, and if your ignition ground is to the firewall or other sheet metal, install a ground wire from that to the drive train.

Steve
 
Caps1.jpg


Caps2.jpg


The year of the problem car wasn't mentioned, but here are pictures of the 28-9 caps. I hear mention of the gasket blocking off the vent holes, but that isn't possible with this style cap. I took these pictures when I took the caps apart to remove dents in the outer covers. It's an easy job to unsolder the inner threaded part from the outside, then the dents can be worked out and the 2 parts resoldered. Just don't get solder in the vent paths.

Of course the radiator cap on the right has no inner vent holes, even though it uses the same outer shell with the 6 vent notches.

The cap on the left is a chrome plated steel repro gas cap.
 
Not every one will agree,but I think the best fix for a failing electronic ign is to go back to the simple original setup.With the correct wire under the breaker plate & the improved condenser,they are practically bullet proof if given a bit of service from time to time.
 
While I had the gas tank drained I replaced the shut off valve (the old one never really quite shut all the way off) and installed the screen filter on it. I also replaced the gas cap and have been driving trouble free for over a week. I didn't do anything to the ignition system so I am pretty sure that the gas cap venting was the problem.
Thank you all for your input. Great forum!
 
I had a problem with the FUSE Block. I lift out the fuse when its gonna set for awhile. Noticed the amp meter needle woudnt move while trying to start the motor,used a test light and sure enough the Fuse was not making contact ,test light would light up on the HOT side ,but not on the other end. Removed the fuse and bent the contacts on the fuse holder, replaced the fuse,test light lite on both sides ,turned on the Switch and tried the starter and the amp needle started moving back and forth and she started right up. This could be your problem if you have a fuse block. Just my thoughts.
 
I dont care for the fuse blocks that the vendors sell.Either the rivetgets loose or the fuse clip overheats & looses tension.I use a 30 amp breaker in its place
 
You must log in or register to reply here.
Back
Top