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hot start issue

ksurfer2

ksurfer2

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So, still working out the bugs in my...new to me...car. Motor is a 512, crossram intake with dual edelbrock carbs. 10.25:1 compression, solid flat tappet cam. Electric fuel pump set at 5.5psi. MSD 7 ignition box. Running on 110 octane race gas. When cold, the car fires right up. I don't even need to touch the gas, just hit the start button and it fires....probably less than 1 second of cranking. When cold, starting the fuel pump will show 5.5psi at the regulator prior to starting. Last night, I took the car on its first excursion...out to a local ice cream shop. After sitting for about 30 minutes, the motor would not fire....It would crank without even a hint of trying to start. Fuel pressure gauge stayed at 0 with the pump running. Speaking with the previous owner, he stated that the car was prone to flooding and often needed a shot of starter fluid to start. I took off the hood and air cleaners....even spraying the starter fluid, the motor would not even try to fire....just crank. After sitting for about another 30 minutes, the motor fired right up. no starter fluid needed. Does this sound like a vapor lock issue? Flooding issue? Would that cause the fuel pressure to go to 0 with the pump running? Fuel line is run through the fender and no where near the headers.
 
ksurfer2 said:
So, still working out the bugs in my...new to me...car. Motor is a 512, crossram intake with dual edelbrock carbs. 10.25:1 compression, solid flat tappet cam. Electric fuel pump set at 5.5psi. MSD 7 ignition box. Running on 110 octane race gas. When cold, the car fires right up. I don't even need to touch the gas, just hit the start button and it fires....probably less than 1 second of cranking. When cold, starting the fuel pump will show 5.5psi at the regulator prior to starting. Last night, I took the car on its first excursion...out to a local ice cream shop. After sitting for about 30 minutes, the motor would not fire....It would crank without even a hint of trying to start. Fuel pressure gauge stayed at 0 with the pump running. Speaking with the previous owner, he stated that the car was prone to flooding and often needed a shot of starter fluid to start. I took off the hood and air cleaners....even spraying the starter fluid, the motor would not even try to fire....just crank. After sitting for about another 30 minutes, the motor fired right up. no starter fluid needed. Does this sound like a vapor lock issue? Flooding issue? Would that cause the fuel pressure to go to 0 with the pump running? Fuel line is run through the fender and no where near the headers.
Click to expand...
I was actually thinking about posting here for a similar issue. Same thing, if it is cold it will fire as soon as I bump the key. If it has been running, then I have to pump the throttle, or hold it to the floor to get it to start, almost like it is flooded.
I even wired the choke open to ensure it isnt flooding the engine... no change.
I will be watching this thread with interest.

Cheers.
 
You do not say if it has a choke.
If you do not need to richen it with a choke or pumping in gas with the accelerator pump it may be to rich. Rich when cold it will start but different story when it is hot.
 
ksurfer2 said:
So, still working out the bugs in my...new to me...car. Motor is a 512, crossram intake with dual edelbrock carbs. 10.25:1 compression, solid flat tappet cam. Electric fuel pump set at 5.5psi. MSD 7 ignition box. Running on 110 octane race gas. When cold, the car fires right up. I don't even need to touch the gas, just hit the start button and it fires....probably less than 1 second of cranking. When cold, starting the fuel pump will show 5.5psi at the regulator prior to starting. Last night, I took the car on its first excursion...out to a local ice cream shop. After sitting for about 30 minutes, the motor would not fire....It would crank without even a hint of trying to start. Fuel pressure gauge stayed at 0 with the pump running. Speaking with the previous owner, he stated that the car was prone to flooding and often needed a shot of starter fluid to start. I took off the hood and air cleaners....even spraying the starter fluid, the motor would not even try to fire....just crank. After sitting for about another 30 minutes, the motor fired right up. no starter fluid needed. Does this sound like a vapor lock issue? Flooding issue? Would that cause the fuel pressure to go to 0 with the pump running? Fuel line is run through the fender and no where near the headers.
Click to expand...
ksurfer2 said:
So, still working out the bugs in my...new to me...car. Motor is a 512, crossram intake with dual edelbrock carbs. 10.25:1 compression, solid flat tappet cam. Electric fuel pump set at 5.5psi. MSD 7 ignition box. Running on 110 octane race gas. When cold, the car fires right up. I don't even need to touch the gas, just hit the start button and it fires....probably less than 1 second of cranking. When cold, starting the fuel pump will show 5.5psi at the regulator prior to starting. Last night, I took the car on its first excursion...out to a local ice cream shop. After sitting for about 30 minutes, the motor would not fire....It would crank without even a hint of trying to start. Fuel pressure gauge stayed at 0 with the pump running. Speaking with the previous owner, he stated that the car was prone to flooding and often needed a shot of starter fluid to start. I took off the hood and air cleaners....even spraying the starter fluid, the motor would not even try to fire....just crank. After sitting for about another 30 minutes, the motor fired right up. no starter fluid needed. Does this sound like a vapor lock issue? Flooding issue? Would that cause the fuel pressure to go to 0 with the pump running? Fuel line is run through the fender and no where near the headers.
Click to expand...
 
Running dual setup on street is tough. Had same problem Yrs ago ran a (b)block w/dual quads,solid lifters etc, had several issues I had to fix! Too hot water temp.( Recore rad),bad vapor lock,(reroute n wrap fuel line)increase fuel psi to approx 6.5. Many adjustments to timing. Leaned carbs down a couple steps. Finally had to wire a separate ignition switch from keyed one. Was a long process of elimination. Note: check your oil for excessive fuel odor. Mine almost washed the rings out?
 
Whenever this happens you have to determine whether it is getting gas and spark.

Looking into the carb, give the carburetor linkage a pull and see if the squirters give a good squirt. If no squirt, no gas.

If you have gas, pull a plug wire or the coil wire and find a place to hold it near a bolt (ground) with a small gap and crank the engine looking for a spark.

You have to start with this to tell what's going on.
 
Are you running a vent line back to the tank?
 
khryslerkid said:
Whenever this happens you have to determine whether it is getting gas and spark.

Looking into the carb, give the carburetor linkage a pull and see if the squirters give a good squirt. If no squirt, no gas.

If you have gas, pull a plug wire or the coil wire and find a place to hold it near a bolt (ground) with a small gap and crank the engine looking for a spark.

You have to start with this to tell what's going on.
Click to expand...
Thanks. I did look for fuel and could see it squirting. I will check for spark next time.
 
ksurfer2 said:
Thanks. I did look for fuel and could see it squirting. I will check for spark next time.
Click to expand...

If you had gas then it could be the pickup in the distributor by the way you described having to wait 30 min before it would start again. They're known to act this way when going bad. They work with cold or normal operating temps but when they get hot they lose connection.

Edit: If you do have spark then it might be a flooding issue.
 
If you are possibly experiencing vapor lock I would think that could cause a temporary loss of pressure if the fuel isn't in a 100% liquid state like it is during a cold start. Hence, easy restarting after an hour cooldown. Just a thought.
 
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Just thinking out loud...if it is a flooding issue when trying to restart, when shutting the car off, would turning off the fuel pump and letting the car "run out of gas" to shut off solve the flooding issue when trying to restart?
 
Tomorrow I will pull plugs to see if its running rich and set idle mixture.
 
Might want to confirm float level settings and ensure no needle/seat issues.

Edit: What is your initial timing setting?
 
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if you have a ir temp gun, it would be interesting to see float bowl temps after being driven and parked. See what they are and then wait that extra 30 mins and see what the temp is again. Also if your fuel line is close to exhaust it might causing you probs away from motor. The comment about distributor pick up is spot on as well.
Back in the day I had a 75 280z FI motor. it would vapor lock on a hot day. I wound up putting spark plug wire heat resistant insulation on all the fuel rails that were above intake and exhaust manifolds.once I wrapped the fuel rails...no more hot start problems.
 
Last edited:
update....Spent a couple hours in the garage today. Started by adjusting the idle mixture screws. I ended up taking about 1.5 turns out of each of the screws. They were all set about 1.25 turns out. Idle needed a slight adjustment down. After shutting the car off, I noticed that between the fender well and carbs, the fuel lines were pretty hot, so I went to the store and got some heat wrap. After wrapping the lines, I went for a drive. Once everything was good and warmed up, back to the garage. When i pulled into the garage and put the car in park, idle speed went to about 2000rpm. I adjusted to about 1100. I then let the car sit for about 30 minutes. After sitting the car fired right up, but wouldn't idle and stalled. After stalling it would not start....back to crank and no fire, 0 psi on the fuel pressure gauge. While waiting for the car to cool down, I put another 1/8th turn into the idle mixture screws and a small turn to the idle speed screws. After only about 10 minutes, the car fired right up and idled fine. I did check the fuel pressure gauge again after the car was running....still 0 psi. This is what I am really baffled about!

Also, I shot the fuel bowls with the temp gun while waiting to restart the car, they were at about 125 degrees. Could this be an issue?

I did pull a plug, and it looks like I may be running pretty rich. I'll try jetting down the primaries next weekend and see if that makes it any happier.

Still looking for any input or suggestions...especially about the fuel pressure.
 
Sometimes those fuel pressure gauges can cause problems and give false readings.
I have one I install initially or while the engine is on the dyno being tuned and then I take it off again and put it on the shelf. They crap out if left on the motor.
Maybe try another one?
I said in an earlier post your car may be running to rich. That may be all your problem is.
When cold they need to be lean enough to be a bit temperamental and then they come right when they warm up.
A car with a carburettor that starts and idles dead cold is almost always to rich when it warms up.
 
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