Car Keeps Shutting Off

[JMF]

Hi guys, only had my Coronet a week and have broken down twice already so going to need some help.

It's a 69 Coronet with a 383 V8 and 4 Barrel Holley Carb.

Basically it starts up fine and will drive ok for about 30 minutes but then it will shut off when driving like it's run out of fuel(it has plenty of fuel in it), when you try and start it up again, the first few times it will start up briefly for a few seconds then shut off again, after the first few attempts it will then not start up at all, it will then need to be left for about an hour to cool down and then it will start up perfect and run for about 10 minutes before just shutting off again

The first time I broke down was the day I got it and I was with the previous owner still, he had a spare mechanical fuel pump and replaced that which I thought may have cured it but no joy.

He said he did have a similar problem 4 years ago when he first got it and he replaced the fuel pump pushrod and it's been ok ever since up until now, so could it be another faulty pushrod ? Or maybe a fuel evaporation problem ? If you look at the below pictures I noticed the fuel hose to the carb is sitting really tight on the distributor and the distributor was very hot, could this be the problem ? Maybe re-route it and get a braided hose ?

Car runs ok when it's driving and temperature is about 180F and goes to about 190F in traffic, it seems to shut off around the 190F mark.

The engine bay does feel very hot when you open the hood but am I right in thinking that's pretty normal for a big engine ?

Thanks for any help.

[Barfyspitz]

Yeah I'm not an expert but that fuel line runs right up against the block it might be heating up your fuel hose and percolating you might want to run  the fuel  line along the inner fender away from the engine Plus those tight bends in the fuel line rubbing up against the engine will rub through spraying gasoline alongside your engine and exhaust manifold

[K9COP]

Bud, follow my '440 cutting out, help!' thread. There's lots of info on there and solutions. PM me anytime and I will do all I can to help.

K9

[JMF]

Thanks for the replies, I took it out again today to get a better idea and it broke down again

Cruising along it shuts off then briefly comes back again a few times before just quitting altogether, exactly like it's run out of fuel.

Took the air cleaner off and there is fuel squirting in the carb when trying the throttle, the AA recovery guy checked for a spark also and there is a spark too, he seems to think it's the fuel pump.

I'm still unsure though because surely if it's a faulty fuel pump or push rod it would not run hardly at all even when cold ? Why would it wait 20 or so minutes to shut off ?

Wouldn't start again for about 90 minutes then after that it started straight up perfect.

He also noted that the fuel hose going to the carb didn't feel like it has much pressure.

I think i'm probably just going to change to an electric fuel pump and see if it still happens.

[RECHRGD]

Coil may be crapping out when hot.

[K9COP]

Follow my thread again. Get a fuel pressure gauge inline to ceck you're reliably getting fuel. Replace fuel filter with a clear one for now.  Also on my car I rigged up an LED to the coil +ve terminal so I could see that the electronic  ignition module was supplying the coil reliably. The LED is on the dash next to the tach. As stated above, route the fuel line along the inner fender AND insulate in. Look up 'vapor lock' on here. Check your msd connections for signs of arcing. Consider a carb spacer and check your vacuum routing.

K9

[K9COP]

Coil may be crapping out when hot.

Excellent point. I just swapped mine....

K9

[ws23rt]

I had a kinda similar problem with my 70 charger once.  First I need to add that I don't think my adventure is what is going on here.

I was driving on the freeway at speed pulling an empty trailer. The car shut off and I coasted to a stop.  The stop was so sudden I was sure it was electrical.--Not--The fuel pump broke. The top of the fuel pump was loose from the body  
So I hitchhiked a ride to get another one. (we used to do this sort of thing long ago).

Installing a new fuel pump on the side of the road with minimum tools is not a rewarding task.

Now I'm on my way and start to feel the engine cutting out. It stopped a few times but started right back up. I noticed the cutting out was on any uphill grade.----

What I found was a pinched hose connection at the fuel pump. I could only feel this as it was out of view.  When I replaced the pump I connected the hoses when I could get at them and then maneuvered the pump into place.--Pinching one of them enough to cause the engine to starve. BTW I had a vapor separator can as part of my situation.

Sometimes a story like this might help someone that has a head scratcher.

I've been driving these cars for many years and have had most things that can go wrong happen. What I don't understand is why do new things happen? ---Is it a test of some kind?

[69wannabe]

Coil may be crapping out when hot.

X2!!!!!

[70 sublime]

Could it be the vent on the gas tank is plugged ?
If it happens again try popping the gas cap

[Barfyspitz]

If it's the coil will doing good but definitely reroute your fuel lines. That is a fire hazard begging to happen

[Dino]

Definitely make the fuel hose route a priority.  The rubber hose is alright but it cannot move around or it may rupture as mentioned.  You can use heatwrap around the rubber hose as well.  That will fix any heat issues.

The bay should be warm when you pop the hood, but not so hot that you feel like you're in a sauna.  I have headers and ir really doesn't get super hot under there.  With manifolds it should be even less.  Is your timing set up properly?  That can rewally raise the underhood temp.

A busted coil is very possible.  They tend to do well when cold and then crap out when hot. 

The carb may need some attention, but I don't think it's the main issue here.  Still it'll be a good idea to open it up and maybe rebuild.  Set floats and all that.

Fuel pump or push rod is always a possibility with these things. 

So secure and protect the fuel line first, check timing, check for vacuum leaks, check the condition of the plugs.  If you find timing needed adjusting then try again and see if anything changed temp wise.  Install another coil and see if that takes care of it.

Then I'd move to pump and push rod.   If they are old you may as well replace them.  That's not going to break the bank.

[K9COP]

Agreed. Guys, we have three very similar threads running here (this one, my 440 cutting out, and 'fuel pressure issue'), can we combine or at least link them? Or maybe choose one for the advice to be added to?

K9