I've read a lot of people have hot start problems with 69 C3's which is what I'm faced with. Starts cold no problem, I think I've narrowed it down by reading the threads to either a fuel vapor lock, leaking metering plate in the 4160 Holley carb, a low voltage at the coil when the engines hot or too higher fuel pressure at the carb.
I don't know the answers to any of these potential causes as yet but I'm a bit confused about this calibrated resistance wire that is supposed to run between the ign sw and the coil and whether I do or don't need a ballast resistor. I think I have the resistance wire, the loom was a replacement loom so I can see the colours pretty well. There is a yellow and a white with a red tracer crimped together and a red going to the + on the coil and a green that is running from the distributor. There is no ballast resistor in the circuit. The details on the Mallory series 42 breakerless distributor say "Make sure the vehicle is equipped with a ballast resistor OR a loom resistance wire" The car has been running ok for years except it has had this hot start problem for as long as I can remember. I changed the started motor a couple of years ago because I thought that was the problem and it was a problem but it seems I have two problems. Before I changed the starter it wouldn't crank when hot now it cranks fine but wont fire when its hot. If I wait 5 mins it will start MAYBE. I also had a fuel pump fitted as I thought it might be a weak manual pump, hence the concern about pressure.

I know lots of people have this problem but can anyone steer me to good order of troubleshooting to try and eliminate what's happening here and do I or don't I need a ballast res, or is the yellow or white cloth covered wire going to the coil doing the job of reducing the current to coil. This is some supession that I might have damaged the ignition module in dist. but as it runs fine when it's cold doesn't missfire at revs above 3000 it seems like it might be ok.

Help, thanks.

 

I'm an amateur at this, but have had similar problems.

I do not know about the ballast resistor as I have converted to an HEI distributor which eliminates the resistance wire and the ballast resistor. HEI requires at least 12V to the positive connector to the distributor (NO resistance wire is used).

I connected a voltmeter to my coil and checked the voltage with the key ON.....then with the key in the START position with the engine cranking. I saw the voltage drop down to 3 volts while cranking. My problem was a corroded terminal INSIDE the fuse box....after replacing the terminal the coil received the correct voltage.

Remove one of the spark plugs/place the spark plug wire onto the plug and lay the plug on metal where you can see the spark while cranking the COLD engine/the spark should be blue. Reinstall the spark plug and drive the car until it will give you a problem restarting it/remove the spark plug while the car engine is hot (wear gloves) and check the spark while cranking the engine to see if it is a blue spark, or it has degraded to a yellow-looking spark.



I had problems with the fuel "boiling" causing the carb bowls to be empty any time I stopped and turned the engine off. I replaced the old thermostat, the old coolant, and installed the foam seals that were missing across the top of the radiator support so air would not divert over the top of the radiator. I have also read that a rusty/sticking Exhaust Heat Riser Valve can cause hot-start problems because it supplies too much hot air to the carb.

I also replaced my old mechanical fuel pump with an electric pump. The fuel pressure was too high by 4 lbs according to the mini-gauge I installed before the carb, so I added an adjustable fuel pressure regulator to get the correct pressure. My Holley had a leaking Power Valve which I replaced.

Make one change/correction/repair at a time! Then you will be able to notice any improvement.

 

can you point your finger to the most likely culpret,,....fuel,,,,or ign. or heat. i know its hard to really know,,, thanks

 

I would buy a spare plug for $2.00 before doing all that ****.

In the points days, an orange spark meant a bad condenser. With HEI, I would like to know. Mike???

 

All three caused my hard start problem, which took a couple weeks to solve.

Start looking at voltage/ignition/spark first....

Then the possible fuel over-pressure problem once the engine is running so you can get an accurate pressure reading while the engine is taking in fuel from the carb.

Then correct any overheating problems. If the engine temperature spikes, overheating needs to be corrected first.

 

Hard start heat related?

Fuel issue like vapor lock, dry carb bowl (Boiling), low fuel pressure, clogged fuel filter/backwards.

HEI? Module. Heat kills em. Either sudden death, or intermittent, the one that makes Sparkies crazy.

Coil (Rare) Wires, how old? Incorrect wires cause issues.

 

The Mallory Series 42 Comp S/S doesn't have a HEI as far as I know its just a breakerless ign dist. that works with stock ign coils.
Plug wires and coil lead are all new.
I have a phenolic spacer between the manifold and the carb.
I haven't checked the voltage drop because I'm not sure if the same test of voltage drop between points open and points closed works on the breakerless system can someone confirm this will still work if I bump the engine and get the rotor in the right place will the voltage drop??
Engine runs cool and I have a slightly lower thermostat than standard. I seem to remember I put a 180 in there. Gauge reads about 180-200 at full operating temp. I can check spark with a spare plug, any thoughts about fuel leaking into the manifold. The car does always have a strong smell of gas, can't find any fuel line leaks or external leaks around the carb but I don't think you would ever see that anyways because any leaks would evaporate immediately. Doesn't seem to smell fuelie when it's cold and sitting the garage however and if it was a leaking metering block my thought is it would smell all the time. If it's a dry float bowl how can I check that? You can't see it through the sight holes.

 

I used a mallory unilite in my vette for many years. You can get the manuals online. Mine required a ballast resistor also unilite used an optical module. In 10 or 12 years I had one fail. I pulled into a store and shut off the hot motor. When I came out 3 minutes later my vette wouldn't start. I didn't have any spark. I called up a friend to bring a meter so we could check out the electrical. Any after it cooled off it fired right up. I called mallory and they told me to replace the optical module

 

You describe the two stock cloth covered wires joined at the positive terminal at the coil. There is no ballast resistor on a 69 but the cloth wire going to the coil from the fuse box IS a resistance wire or as described, a loom resistance wire. The resistance is built in to the wire. The other cloth covered wire goes from the same + terminal at the coil to the 3rd terminal at the starter. This wire supplies a full 12 volts to the coil from the starter terminal when the key is in the start position only as the reduced voltage through the resistance wire is sometimes not enough to start the car because of the drain when the starter is engaged. You said you replaced the starter. Did you use a 3 terminal stock type starter or a 2 terminal one with the bypass cloth wire left disconnected? If that wire is not connected at the starter you might not have enough voltage to supply proper ignition voltage when the key is in the start position causing a no start condition.

 

when the engine is hot look down the primary and secondary throttle bores to see if gasoline is dripping into the intake. If you see gas dripping check the float levels.
Your car originally had a fuel filter mounted in front of the passenger side cylinder head with a 1/8" fuel return line. Do you still have the return line connected?

 

Ooo that's interesting, I'm not sure I'll have to get the car up and have a look. I replaced it with one of those small gear ratio high torque starters because I had heat problems with the old original. Not sure about that extra wire, does it matter which terminal on the starter it's connected to?

 

Fuel return is still connected and there is still a fuel filter mounted on the passenger side of the block. Not sure if this was standard or not but photo attached.

 

You can't connect the stock bypass wire with a 2 post mini starter. You need a 3 post starter with the extra R terminal. The large main terminal is powered all the time so you can't connect there. If you connect the bypass wire to the small S terminal voltage will feed back from the coil anytime the IGN key is on and power the starter to engage. To use the bypass wire with a 2 pole starter you have to hook up some sort of relay that prevents voltage feed back from the coil when the starter isn't engaged. I would think if you don't have the bypass wire connected that is probably the cause of your hard starting when hot due to the large voltage drop (hot starter/hot engine) in the already low voltage through the stock resistor wire.

 

That's pretty scary .

 

The stock metal fuel filter had a return nipple on it so how is your return line connected currently?
Using a plastic filter and rubber hose on the front of the engine is really a bad idea.

 

Not sure that's the way it was when I bought the car and I never changed it. What problems are there with the way it's set up now?
I'll look online to see if I can find a picture of how it's supposed to look.

 

Has anyone got a photo with the correct fuel line connections for 650 Holley, I can't seem to find a photo without an air cleaner in place, sounds like I need to fix this as well.

 

Mel do you have any photos of the correct fuel line connections to the carb. Is it just one line in, I've seen some with two lines but I'm guessing that's for a double pumper. I don't think the return line is connected I think it's capped off.

 

below is a link the original type of filter with a nipple to connect the return line. You can either get the original steel line from the pump to the filter along with the steel return line from the filter to the frame or use AN type hose and get rid of the rubber and plastic.

 

Thanks, Is it ok to cap the return line and run without it?