Hot Running/Starting Issues
 

Hi all,

Firstly, after 5 years of being cobra-less and increasingly feeling the need to have one in my garage, I took the plunge and recently purchased a CSX6000 series car. The car looks to have been beautifully put together with the 468FE/Holley carb installation been done by V”Superformance sometime in 2016. Since then the car has done less than 1000 miles.

So here is my issue that I would be grateful for some advice on so I can run the problem to ground:
When the car is cold to reasonably warm it runs perfectly - very responsive throughout the rev range, idles nicely and restarts easily. However, I took it for an extended run yesterday and when the car got hot after about 30 mins of driving, the engine started to stutter and stall and left me stranded at the side of the road. The engine would restart after a lot of cranking (starter and battery are both strong) but would die again almost immediately I started driving with black smoke coming out of the side pipes. I then let the car cool for about an hour and it immediately started and ran perfectly for the 2 mile drive back to my home.

Does this sound like an ignition problem? The car has an MSD distributor and coil with an MSD Streetfire 5520 ignition box mounted under the dash of the passenger side.

Any and all advice gratefully received - thanks.

Sound like possible fuel vapor lock.
Stop and go traffic?
Steady state highway speeds?
Mech or Elec fuel pump?
Return or return-less fuel pressure regulator?
Insulated fuel lines?

Some pics of the engine compartment would help.

Can also be the carb itself getting hot. An insulator type base gasket can help.
https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

How old is the gas in the tank?

I had an MSD box go out when hot awhile back. Although the box was in the passenger compartment under the dash.
It would hard die not sputter and emit black smoke like a vapor lock will.

If you want to troubleshoot the ignition once it fails: To check the Box, coil, mag pickup.
https://www.holley.com/support/troub...ng_techniques/

Or take a spare spark plug with you. Pull the most convenient accessible plug wire and jack the spare in, lay the plug against the intake manifold to get a ground on the base. Have someone crank the engine and look for a spark.

Looks like an issue with your carburetor running rich. First thing, if you have a choke make sure it is fully opening when the engine is at full operating temp. If the choke is not the problem, the carburetor is either not jetted properly or is not functioning properly. If you are not up to diagnosing the issue, bring it to someone who can diagnose and correct the issue. Driving the car while it is running excessively rich will damage the engine.

spdbrake - thanks and to answer your questions:

1. I was in stop and go traffic
2. The car has both mech and elec fuel pump but i was using only the mech one
3. Sorry - don’t know what type of fuel pressure regulator is on the car, same with fuel lines but pic attached.
4. The gas in the tank is fresh

Thanks.

Make sure you have a breather / tip over valve on the gas tank......if there is not one it will suck a vacuum in the tank and stop the gas flow.......until the vacuum subsides.

ERA174 - thanks. There is no choke on the car but yes, it could be running rich and the carb will be checked out at the garage tomorrow. I just thought it odd that the car ran perfectly when cold to warm, i.e the first 15/20 mins of stop start and highway running and then the problems began.

Sounds like vapor lock. Boiling fuel in the float bowls. Does the carb have a spacer between it and the intake manifold?
If you have a switch to turn on the radiator fan, (the one on the back side of the radiator) try leaving the fan on while driving in stop and go traffic and see if that helps.
Try the simple things first. Since it runs great until heat builds up, that should be the culprit. And with less than 1,000 miles in 4 years, my guess is the previous owner never drove it long enough for the problem to surface.

Thanks CHANMADD, I will check.

Call Vlado at Vs performance... he will help you.

I had the same issue with my ERA car, when you turnoff the car while HOT open the hood and remove the air filter. Check to see it the jets are dripping fuel into the carb causing a rich condition. I some times had to put my foot to the floor while cranking the motor, this would empty the float bowls.
Annoying to say the least.

Thanks and there isn’t a spacer so could be worth getting one. Also, removed the air cleaner and was surprised to see that two of the barrels were coated with carbon but two were clean - not sure if that points to anything in particular as the cause though.

ERA626 - Thanks and a call to Valdo at V’s is a good idea as is the Hot check.

Pretty much the same issue I had about a year ago right down to the black smoke. Ran fine till heated up. Stalling. Hard starting. Black smoke. Only happened after car ran for a while. Went right to the carb to check for leaking fuel, fuel pressure, vaporlock, float levels, leaking needle and seats etc. Turns out it was the coil. MSD ignition. Changed the coil. Problem was gone. I would have sworn it was a carb issue. Found the solution on the Holley forum.

Fred

FYI I have CSX 6079

Thanks Fred - that’s exactly the same issue! The car is back at the garage for diagnosis now and I will post up what they find is the cause.

I have been following your build and I love your color combo - congrats!

My guess is it is the winter fuel there in Texas. I experienced the exact same symptoms many years ago while at the annual TCC meet. Try adding some fuel conditioner and see if that helps.

Yes, an electrical component that's heat sensitive could well get flaky once it heats up, then resume normal operation once it cools down. It may do this a number of times until it ultimately fails.

I didn't have that problem, but did end up frying the original analog MSD 6AL box. It was mounted on the firewall, with an oil-filled coil on the front of the engine. The replacement (digital) box is above the passenger footwell, and the replacement coil is epoxy-filled and mounted on the firewall.

Andig
 

As a quick followup to my post. The problem appeared suddenly one day when the car stalled and wouldn't start after riding around a while. I got it started by holding the pedal to the floor. That is what threw me off and started looking at the carb. I went through this for weeks till I changed the coil. You know the rest from my previous post. Additionally, I am not in favor of the location of you coil. They are susceptible to heat. My coil is different and located on the inner fender. Good luck. Can't wait to hear the solution

Fred

Thanks Fred and for everyone’s responses.

It looks like the culprit is the distributor cap (see pics) and since fixed, appears to be running normally even when hot.

Fred, I do like your fender mounted coil and will look to get one of those.

Andy