Help with Old Mustang -

I’m going to apologize in advance for not having all the relevant info.
A good buddy of mine has a 1970 Mach 1 Mustang. He has a habit of dumping a bunch of money into, driving it for a few weeks, and then putting it in storage until it needs more money dumped into it.
When it runs, the thing is a beast.

Several years ago he had the entire drive train replaced by a mechanic, who I assume has a VERY nice boat. Aluminum racing block engine, headers, stroke kit, BIG carb, new transmission and rear end, and new gas tank.

A few weeks ago, I harassed him enough to try to get it running. The things that were previously replaced were fine, but EVERYTHING leaked. Ended up taking it to a different mechanic (that I’m sure is going to buy a very nice boat) who replaced a multitude of hoses, belts.etc and put a new bigger fuel pump in.
Car ran great. You could set off alarms driving in the parking garage.
He let it sit outside for the first time ever and it rained. Of course the car wouldn’t start. It would crank, and flood the engine, but not turn over.

He called me to come help figure it out. Somehow, I am the friend that knows the most about cars. Clearly he needs new friends. What little I know, I learned from listening to car talk as a kid, and attempting to keep my old beater truck running.

So, I get to the car, and there is water on the driver side floor board. There is a noticeable gap between the the windshield and the hood. I think rain came in and ran behind the dash.
Pop the hood. The new fuel pump has a electric line running to it, with an inline fuse. I check the fuse. It’s fine. Battery is connected. It starts up.

I didn’t do anything, but it’s “fixed”. We drive it around for the afternoon and have a good time.

It has been in a garage (and dry) the last few days. He tried to start it today, and it won’t turn over.

From what I can tell via text message -
It cranks but won’t start. He has to give it gas, when he starts it, normally. So not starting up makes the engine flood. It seems to not be a fuel issue.
I asked if he had tried using starting fluid and was told “I tried dumping ether in there and taking the air filter off”. (Interpret that how you will).

It seems to be getting fuel.
I can’t imagine the air way has clogged in a week.
The spark plugs are new, and worked last week.

I’m going over tomorrow with my tool set, multi-meter, spark tester and and jump pack.
He says the battery is good, but I figure I’d check that.
I’ll test the plugs and plug wires. Double check fuses and relays.
I’m assuming the carburetor has a choke, that I can make sure opens…

What else should I be paying attention to?

Is there anything behind the dash, besides the ignition that could short out if it got wet? I’m assuming that if the engine is attempting to start at all, that the ignition switch is fine.

Thanks in advance.

Don’t drive like my brother.
Seriously, the boy runs into trees.

I think its a electrical connection. you shut the hood when it did not start and all of a sudden it works. shutting the hood shock the car enough to make the electrical connection.

Look under tne dash with a light. The cowl under the vent in front of tne windshield can rust through even on a rust free car.

The car came from the factory with a mechanical fuel pump. The electric is an add on.

Look for spark, fuel and compression like any engine. Go from there. Impossible to direct you further 'cause we don’t know what has been replaced or kluged to make this beast run.

1 Like

I didn’t read the entire thing, but the cranks but doesn’t start problem sounds like a no-spark issue. Suggest to have a helper check for a strong blue-white spark at a spark plug while cranking the engine. If you see a spark, but it has a red hue, that’s not strong enough to start the engine. I had that exact problem on my truck two summers ago, a reddish spark color, had to clean the contracts on the ignition points to get it to start. If the spark looks ok, there’s more steps to follow. Suggest to do the spark test first, and report what you find. I’m guessing you’ll find there’s no or a weak spark.

Would be helpful if you provided the basic ignition system configuration. Distributor or coils on plugs? etc …

Keep in mind… 51 year old wiring and ground connections.

Slam the hood and it starts? Loose wire? Bad ground? Some sick bugger swapped in Lucas electrics? Who knows?


It started with the hood open. The wiring has all been replaced, but it sounds electrical to me. I’ll start there. I’ll report back if we get it running, or with more complete information.

Wanted to make sure I wasn’t overlooking something obvious.

For sure. I’ll have those basics after I look at it.

Once you get it working again, the next job is to make sure that the rain water that hits its surface has a clear path to the ground via the car’s drain system. That can prove to be a pretty big job, but is usually diy’er doable, just takes some patience & time.

Yeah, that’s a whole separate issue. Just helping it get it running bc his boy just turned 5 and thinks this car is the coolest thing he’s seen in his life. He’s not wrong.


You said you fiddled with the wiring and fuse for the fuel pump before it started. I’d be looking in that area again first. Possibly it isn’t getting fuel, poor wiring job on the fuel pump install, etc.

If it’s getting fuel and not spark, check the wiring to the coil. I imagine this old Stang has a single coil. Loose connection there could have you dead in the water.

The sitting outside, rain, etc may or may not be related. Might be a coincidence.

1 Like

The rain comment leads me to think moisture has bascialy shorted out the coil or distributor cap. On rainy or high humidity days moisture can condense inside the dist. cap and that will prevent an ignition spark.

Here in OK we have horribly high humidity which causes problems like this; especially in the fall and it’s even worse when it occurs after a hot engine is shut off. Heat attracts moisture in the same way a home window may sweat.

My Sonoma was going through this. Every time it rained or the humidity skyrocketed either a no-start or sluggish running for the first few minutes. I used a small brush and swabbed the inside/outside of the dist. cap, coil wire, and coil with dielectric grease. That fixed that problem.


Hope not to offend others, press the gas pedal down once and make sure the choke sets.


I too go with moisture in the distributor. The other thing, the electric fuel pump could be providing too much pressure, flooding the engine.


I am more inclined to think this is a carburetor issue. To start those old beasts, you step on the gas half way to 3/4 way to the floor and release, then turn the key. This provides a squirt of gas to the manifold and allows the choke to close. Anymore pumping the gas pedal will flood the engine.

If it starts momentarily but “chokes out” and is then flooded, then it needs a new vacuum pull off or a new vacuum hose to the pull off.

I also suspect the the electric fuel pump may be providing too much fuel pressure and pushing fuel past the needle and seat in the carburetor and flooding the engine that way. He may need a fuel pressure regulator. It should be set to around 3 psi.

He may also need a new accelerator pump for the carb. On a little used vehicle, these tend to dry out and not last very long. Also if he has not upgraded to a good electronic ignition system, that would be a really good investment.

Edit: one more trick to start these, especially if they have flooded. Hold the gas pedal all the way to the floor for at least 30 seconds, then with the gas pedal still to the floor, crank the engine. It should start within about ten seconds, lift the foot quickly when it starts. The thirty seconds allows fuel in the manifold to condense around the intake valves and will clear the engine in the first few crank cycles. At some point within the first ten seconds, the A/F ratio will be perfect for starting and it will start suddenly and really start to rev. My wife did this once but didn’t get her foot off the gas quick enough and over reved the engine breaking a valve spring.

1 Like

Run a file through the ignition points.

1 Like


Distributor cap was completely rusted through.

Tested the spark plugs and plug wires with a multi meter. They all seem ok.

We’ve got a new distributor cab ordered and hopefully that will solve that issue.

How old is the rotor? points and condenser? Plugs? Wires?

I have never seen a metal distributor cap only plastic that don’t rust.


Common problem with cars that age, most likely elecrical.

The immediate solution is to meticulously disassemble, clean and hair dryer every every ignition component, Cap, points and connection. Dry rag, emery cloth and hair dryer,

If that works, replace everything (plugs, wires, points, cap) and take a hard look at the coil.

A race engine with a rusty distributor cap? Any performance cap should have brass terminals.


1 Like