Not Starting When Hot

[Fritz]

Hey, I know this seems to be a common problem, but with all the different answers out there, let me run this all by you:

Freshly rebuilt 239 (6v pos ground) with electric fuel pump, crab distributor with pertronix ignition and coil, and new Stromberg 97 carb. I have 2/0 battery cables and just installed a new Optima battery, hoping it would help over the regular 6v battery I had. The Optima def cranks a lot better. But after I shut the engine off for a few minutes, it still refuses to start until everything cools down again, hours later. It will start again within seconds after turning it off, but after even 5 minutes, it just cranks.

I can smell the gas, and it's getting great spark while cranking. All the gas around me in the Chicago suburbs have "up to 10% ethanol" or whatever ethanol blend it is. Does that sound like the problem? Or?

[mike42]

Fritz.....this comes up a lot here. Have you have the coil rebuilt ? If not there is a guy in Florida who does it and brings it up to date with modern materials to correct this problem your having.

I had the same and no probs now at all.

Mike

[Snouts out]

I'll bet it has something to do with the Pertronix ignition.!

[Old Redneck]

Make sure you have the spark plug wires on correct. I bought a 38 Ford and drove it home and on the way home the car started to slow up and I pulled off the road and the car would not start. It cooled down and started and I drove it home and in the garage and it would not start again. Later I found out the two spark plug wires on the passenger side rear were crossed. After that no more problem. You might just check that for a start.

[Fritz]

I have a 6 volt positive ground Pertronix module with the Pertronix coil. It runs great when I start it cold and drive it. Another thing I forgot to add, is that it will start right up and run great when I push it downhill and pop the clutch in gear.

I also just had the starter rebuilt by a good local shop. I thought that may have been the problem, but it's doing the same as before the rebuild.

[jimTN]

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Sure sounds like the old vapor lock gremlin to me. If it had regular ignition I would say condenser or coil.

[adileo]

Is it cranking strong or does it sound like battery weak or major drain while cranking?

[G.M.]

Being able to start it with a slight push indicates ignition problem not gas.
Pushing and jump starting in gear ONLY takes the amps draw from the
starter out of the picture. When the starter is cranking the voltage to the
coil is being pulled down below 3.5 volts on a STANDARD Ford ignition
system and starting become border line. On your electronic ignition it may
take a little more than 3;5 volts to fire. It's not a gas problem or it wouldn't
start with a SLIGHT push. G.M.

[37 Cab]

I think Adileo and GM are right. Does it crank fast when hot? If not, it is possible the coil is not getting enough voltage to fire because the starter is drawing too much. Check your charging system. It may not be charging enough to keep the battery fully charged. Check generator output at both the battery and the regulator. If there is a difference in the reading you may have high resistance in the circuit going through the amp gauge causing a voltage drop and not properly charging the battery even though the charging system is otherwise working.

[rockfla]

Proper & good clean grounds???

[Cecil/WV]

You don't say what year car this is. If it has a resister in the circuit, put a jumper wire across it and see if it will start.

[RalphG]

I find that the 8ba in my Merc always needs a couple of pumps on the gas pedal before I push the button even on a hot start. No pumps equal no start. Maybe its just mine.

[rotorwrench]

You might check the distributor advance mechanism. It almost sounds like its not retarding like it should. If it's not that, it might be overly rich mixture if the float isn't shutting off the flow to the bowl or there is an internal carb leak. I'm not a giant big fan of Pertronics stuff. I've heard both good and bad. Electronic ignitions can have heat sensitivity if some internal component isn't right.

The original ignition system is very reliable as long as it is in good condition. The way Skip rebuilds those old coils, they are even more reliable than they were when new. Good condensers are another problem these days. It's very hard to find good ones without testing them.

[Fritz]

It's a '41 with a rebuilt crab distributor. Ive double checked the vacuum brake to make sure it's set properly. I can't even tell you how many times I've reset and checked the timing. The ballast resistor is bypassed so the Pertronix coil has full voltage.

I have the Pertronix and crab because the Helmet distributor and aftermarket coils/condensers always fought with me.

Could my problem still be ignition when I still have awesome spark under cranking load, and when it push starts? It cranks good and fast, especially with the Optima battery.

[40cpe]

Maybe it is flooding. You said you SMELL GAS and have a great spark. Leaking power valve?

[Mart]

Try moving the pedal to wide open as you crank. If this helps, it would indicate over rich. Slow movement to open, rather than frantic pumping.

If overrich there could be many reasons.

Mart

[rotorwrench]

The vacuum brake piston might be functioning normally but the flyweights can have problems too. The distributor cam can get stuck on the shaft if it gets crusty. If it is stuck in full advance, it will usually try to kick back but not always. There isn't much a person can do to adjust ignition timing but keeping these components working like they should is a must.

[G.M.]

How long has this electronic ignition been on?? You say you had to fight
the original distributor now your into a battle. Send your original distr, coil
and a few condensers to Skip. Install these with your original resistor and
you will run trouble free for years. If you have problems in the future it is
easy to diagnose with the stock set up. Besides you can do a little cleaning
and adjustment to the stock setup if you get stuck on the road. What's the
solution with the electronic one? G.M.

[FlatheadTed]

Could be incorrect coil but you say it has good spark ,?remove the power valve and plug it up, or get a hand built one from Charlie NY ,Ted

[3twinridges]

I went through this on my 1950 f1 with the 226. Rebuilt the carb, nos distributor, new fuel lines, nos coil, all new wiring, nos regulator, nos solenoid, rebuilt starter, rebuild generator, the works. Even running non ethanol gas.......get it hot and it takes a few seconds to crank. I started trying different start tactics, and that's how I fixed mine. When it's hot, I just barely tap the gas at the same time I hit the start button, I don't race it, but give it enough to level out. Works every time......try that.

[5lugnuts]

You guys know more than I about this stuff but here is my story that might help. If not, I tried. Years ago I had a 51 Ford with exactly the same issue. I checked everything and could not find a problem and I checked over and over again for months. Then one day in the warm weather I was cranking it with the hood up and looking under the hood from the drivers seat as it was cranking I saw what looked like smoke or steam coming off the engine as it cranked. Then as I stood outside and jumped the solenoid to crank it I saw smoke coming from the carburetor linkage where it attached to the carb.

Long story short, a previous owner had disconnected the ground strap that ran from the fire wall to the intake manifold bolt. When I connected that back up, hard starting when hot went away. The only thing grounding the engine and the starter was the carburetor linkage attached to the firewall which would get hot at the connection to the carb (highest resistance) and then burn off the gas from pumping and cranking at the same time. Now I always make sure the engine has a good ground not just the battery.

[WestCoast]

if you smell gas it because the heat from the engine is heating the carb and boiling the gas out of the float chamber and flooding the engine, next time you shut motor down look down the carb throat to see if any fuel is dribbling down the carb into the intake manifold, have you plugged the exhaust manifold gas cross over channel that runs thru the intake manifold just behind where the carb mounts, that channel was used to help warm the carb for better running in real cold weather, also aluminum intakes transfer more heat to the carb than cast iron one, put a phenolic spacer between carb and manifold, the thicker the better to stop the heat transfer to carb, the reason the engine will start right back up is because not enough fuel has perculated out of carb into the engine

[TagMan]

Coil, coil, coil !

[Capt Kirk]

My not starting when hot was due to the old original coil. I don't know anything about pertronix

[Fritz]

Thanks guys. I tried just pressing on the gas while hitting the starter button. When it's real hot, like within 30 minutes of running it, it takes a few cranks, but it starts! Otherwise, a little gas pedal will get it going easy.

Thanks for the suggestions. I think I was afraid of flooding if I gave it gas, but this has worked for several hot starts now, and hasn't failed.

[50fordcoupeman]

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I agree with mike42 and GM.............a bad coil will act like this when it gets hot from ambient engine temp. Good luck!!

[WestCoast]

put at least a one inch phenolic block under the carb to insulate from the intake manifold, and plug the carb pre heater passages in the intake manifold, , it runs just behind and under the carb in the manifold, it was designed to warm up the carb faster in real cold weather, its not needed, aluminum manifolds transfer a lot of heat to the carb and causes the carb to boil the fuel out of the fuel bowl and cause a flooded condition