Car cranks, runs briefly on starting fluid, but does not run

lincoln
engines

#1

So, as the title says, my 1976 Lincoln Continental Mark IV cranks, runs briefly on starting fluid, but does not run. It turned off while I was driving a week and a half ago, and I’ve only successfully started it once since then. I tried replacing the fuel filter thinking it might possibly be clogged (and I have no idea when, if ever, it was last replaced), but it still will not start. What else might be causing fuel to not be getting to the engine?
Thanks!


#2

When you pump the accelerator (or twist the throttle underhood) does the carb squirt gas into the cylinders? If you unhook the fuel line and crank the engine (remove the coil wire first!) does gas come out? If it does the pump is OK and the carb likely needs a rebuild. If not, time to replace the fuel pump. Ethanol in the gasoline has probably eaten the diaphragm in the mechanical pump. Same goes for most of the carb internal seals as well as possibly ALL of the rubber fuel lines in the car.

You have a big job ahead of you checking all this stuff.


#3

Mustangman, does this vehicle also use the old mechanical fuel pump, the one with the diaphragm? If so, it’s one more possibility.


#4

@Mustangman 's advice above is spot on . Start w/all that. Assuming this car is configured w/a carb and mechanical camshaft lobe actuated fuel pump similar to my Ford truck 302 v8 of same era vintage.

I can offer some experience I’ve had w/my truck in the past where I had similar symptoms. Most of the time the problem turned out to be the fuel inlet valve to the carb. It was sticking shut and not allowing any gas into the fuel bowl. That’s a pretty easy thing to check for a diy’er. If there’s gas being delivered to the carb inlet fitting, but carb’s fuel bowl is empty, that’s likely the problem. Usually I could just jiggle it to get it working again. this problem tended to occur if the truck had been sitting for a week or two without being used.

I had the fuel pump fail once. I think it still started, but the problem was pretty obvious since it was leaking gas onto the road. So check for anything smelling like gasoline leaking under your Lincoln.

Just last summer I was tuning up the choke system and had the air cleaner off and idling the engine. It was purring like a kitten for 20 minutes or more, then while I was working away from the truck on something else, for no apparent reason the engine stalled and wouldn’t start after that. Crank but no start. That turned out to be some gunk had fallen into the fuel bowl somehow and got into the carb’s internals. A carb clean out and rebuild fixed it.

My guess, the carb fuel inlet valve is sticking shut. Hope for it to be that, as it is easy to fix.

btw, the fuel filter is probably supposed to be replaced every 3 months … lol … I laugh b/c I didn’t replace it for 7 or 8 years, which probably contributed to my need to rebuild the carb. Rebuilding the carb is sort of a fun project as long as you are not pressed for time.


#5

Agree with Mustangman; items to check and in that order.
BTW, how did you get along with your heater core replacement?


#6

I looked this beast up on RockAuto… 7.5 liter V8 (460 cid) with a mechanical fuel pump and a 4 barrel carb! Serious old school! I think it might have electronic ignition - didn’t check - as the only “modern” system.

I’d guess this baby gets a whole 9 mpg around town and maybe 11 highway. When it runs…


#7

@Mustangman Yep! :slight_smile: Exactly 9 mpg driving around town. At least it has a 26.5 gallon gas tank!

It has cruise control, which, I’m guessing was pretty “modern” for the time. It came with the original receipt and it cost, adjusted for inflation, around $56,000 (assuming I remember the number correctly) with all the fancy upgrades that it had (leather seats, 8-track radio, and special body trim).

I will be checking out all of your suggestions later today when I can brave the nice Iowa weather :slight_smile:


#8

@OldcarsRbest I got the cover under the dash taken off, and I got the core replaced, but since then I haven’t been able to get the cover back on, so I’m working on figuring that bit out.


#9

I think that’s the same engine that they abused the heck out of on Mythbusters. Just to see what would happen. Plugged up the tailpipe, drain cleaner in the fuel tank, bleach in the fuel tank, sugar in the fuel tank, coca cola in the radiator, dropped a penny into the carb. You know what? Nothing they did hurt it. It just kept on running. The only thing that caused any damage at all, overheating, was putting bleach in the oil. One tough beast that Detroit iron.

http://mythresults.com/episode15


#10

Those engines are a tried and true design, but they guzzle an ungodly amount of gasoline

From what I hear, it’s a pretty good powertrain, for a tow rig, if you’re pulling a horse trailer or a boat


#11

@GeorgeSanJose Just saw that episode. They said they used a small-block, and my engine is a big-block. Still really cool, though!


#12

@Mustangman, @GeorgeSanJose So obviously my knowledge of how carburettor fuel delivery works is limited, but I noticed that even after pumping the throttle and cranking the engine, there isn’t any gas in the fuel line leading to the carb. Does that suggest that the fuel pump is bad?


#13

Sure does indicate a bad fuel pump. The engine cranking would actuate the pump filling the carb’s float bowl. Pumping the throttle should squirt fuel in.

It could also indicate a rubber fuel hose somewhere in the line from the tank to the carb has collapsed or melted or cracked due to exposure to alcohol in the gas. The pump would then suck air and not fuel.

As I said before, you have a big job ahead tracing the lines all the way back to and INto the tank.It is an ugly job but if you want this beast to run again, it has to be done.


#14

Alright got it. It seems that a lot of the fuel lines are metal, so it shouldn’t be too daunting of a task, but we’ll have to see.


#15

If you trace it all the way back to the tank; before dropping the tank, fix up a short piece of hose and attach one end to the cars fuel line and put the other end in a gallon container of fresh gas, just to verify that it’s pulling all the way.


#16

Replacing the fuel pump worked! She runs like a dream! I also changed the oil since I was planning on doing it soon anyway, and I read that it’s possible for fuel to have gotten into the oil because of the bad fuel pump/


#17

Good for you for replacing that faulty fuel pump & getting your Lincoln back and the road and purring like a kitten again!

re: faulty fuel pump can cause gas to go into oil

If you replace the pump yourself you probably noticed it bolts onto the side of the engine and covers a hole. That hole is where the arm on the pump goes. That arm contacts with a camshaft lobe (really an eccentric) inside the hole, which pushes that arm back and forth, similar to how those hand operated water pumps at old farmhouses work. That action pumps the gas from the tank to the engine. When a mechanical fuel pump like that fails it is usually that the rubber-like diaphragm inside has split. And that cold possibly allow gas to be pushed into that hole in the side of the engine, rather than to the carb where it is supposed to go. I’m not sure if that is a common failure mode, but yes it seems like a good idea to replace the oil when replacing the fuel pump.

Here’s a tidbit of info that might come in handy. During the install there’s a gasket placed between the pump and the mounting surface. Believe it or not, the thickness of that gasket affects how much gasoline the pump can pump per minute. The thinner the gasket, the more it pumps. B/c that places the arm a little close to the cam’s eccentric. So if you notice the engine misbehaving in situations where a lot of gas is needed, like going uphill fast, that might mean that gasket is a little too thick.


#18

@GeorgeSanJose got it. The pump I got came with 2 gaskets (though the manual referred to them as a spacer and a gasket, but they were the same) and it said to use spacer if needed, but I just used one, and it seems to be working great. Thanks for the info!


#19

Sincere congratulations on a job well done! I can tell by your post the pride you feel, and you have earned it. And sincere thanks for taking the time to post back. A happy ending is always good to hear.

Happy motoring?


#20

So after running perfectly a few times, it is now no longer running again. I replaced the ignition coil because it was testing bad, and I hoped that was the problem. It seems now that not much gas is getting to the carburetor. If I take off the gas line leading to the fuel filter right after cranking the engine, there is almost no gas. Shouldn’t this have a decent amount of gas in it?