1st engine start great - 2nd start not so good

[Jerome P.]

[David H.]

Re: 1st engine start great - 2nd start not so good

After sitting for a couple of days my ‘72 with a couple of gas pedal pumps will start up right away. A second engine start up after driving the car for 10 minutes and then sitting for another 10 minutes on restart the starter hesitates to turn the engine over but then does. On restarts I have try pumping the gas pedal and not pumping. Same scenario.

The battery has a full charge and is in good condition.

Any thoughts, comments, or ideas as to what’s going on?

Jerome,

After 2 hours how does it start?

Stock exhaust?

New or long term problem?

Dave

[Larry M.]

Re: 1st engine start great - 2nd start not so good

Jerome,

Our 1972 LT-1 had a hot start problem at one time that I corrected by re-terminating the wires at the starter. Over time, through various R&R's, a number of the copper strands at the juncture of the wire and the terminal had broke. I installed new terminals cut back 1/2" or so into sections of the wires with intact strands.

Larry

[Jerome P.]

Re: 1st engine start great - 2nd start not so good

Jerome,

After 2 hours how does it start? It starts up. No hesitation

Stock exhaust? Stock

New or long-term problem? Last several months.

Dave

I live in Arizona and it is still hot. 105 plus degrees for highs.

91 octane gas with about 5% of 110 octane gas mixed in.

[Daniel S.]

Re: 1st engine start great - 2nd start not so good

Could be the solenoid getting too hot... has the problem happen frequently? Could be time for a starter rebuild.

Dan

[Harry S.]

Re: 1st engine start great - 2nd start not so good

All good suggestions. I would recheck the battery a cell at a time. Even at a full charge with a bad cell it will cause your problem.

[Patrick H.]

Re: 1st engine start great - 2nd start not so good

This may sound funny, and hopefully not condescending...

Do you know how to properly start a 72, and how the solenoid on the carb works? Given how long you have owned it, I suspect so.

As a point of information for those who wonder:
You have to turn the key to ON before you pump the throttle, hot or cold.
When cold, go ahead and pump it twice. When hot, you only have to pump it once, or even half way. The goal with the sequence is to lift the linkage off the solenoid while it is engaged (powered on) so it can then hold the throttle slightly open at the proper position. Now you can start the car. If you attempt to start it with the throttle down (solenoid not holding it open), it won't start easily or sometimes at all.

Most people pump the throttle twice then try to start the car. If so, the throttle is closed and it's much tougher. All of this is assuming that your solenoid is properly being used to set the idle speed, and not the screw on the carburetor.

Even if you are starting it properly, you might want to verify that the solenoid is actually working and didn't break in the last few months if this is a newer problem.

Patrick

[Gene M.]

Re: 1st engine start great - 2nd start not so good

If battery is good as stated the resistance somewhere is too high. Look at wires for internal corrosion, terminals, starter solenoid internal contacts, starter brushes, battery cables and connections.

If you have a green knob battery cut out......... throw it in the trash. It is made out of a metal that does not react well with the battery posts.

[Jerome P.]

[Jerome P.]

Re: 1st engine start great - 2nd start not so good

This may sound funny, and hopefully not condescending...

Do you know how to properly start a 72, and how the solenoid on the carb works? Given how long you have owned it, I suspect so.

As a point of information for those who wonder:
You have to turn the key to ON before you pump the throttle, hot or cold.
When cold, go ahead and pump it twice. When hot, you only have to pump it once, or even half way. The goal with the sequence is to lift the linkage off the solenoid while it is engaged (powered on) so it can then hold the throttle slightly open at the proper position. Now you can start the car. If you attempt to start it with the throttle down (solenoid not holding it open), it won't start easily or sometimes at all.

Most people pump the throttle twice then try to start the car. If so, the throttle is closed and it's much tougher. All of this is assuming that your solenoid is properly being used to set the idle speed, and not the screw on the carburetor.

Even if you are starting it properly, you might want to verify that the solenoid is actually working and didn't break in the last few months if this is a newer problem.

Patrick

[Mark E.]

Re: 1st engine start great - 2nd start not so good

Gene, if it is a resistance issue, why would it start right up initially and not on subsequent start ups as discussed in my original post? I am not suggesting it isn’t a resistance problem or doubting your opinion, just wondering.

i do not use the green knob.

A hot engine can take more energy than a cold engine to crank. So if the starting system is marginal, it may work ok when cold, but struggle when hot.

Too much static ignition advance can also increase cranking load. Again, this may only be a problem for a marginal starting system during hot cranks.
A

[Don B.]

Re: 1st engine start great - 2nd start not so good

Not to highjack this thread, but thanks for posting this. I have a stock SB 72 and it is just the opposite. I have no trouble starting when it is warmed up, but cold starts are difficult. I have been read in the owners manual where it says to pump the accelerator, but I did not know that the key needed to be on. I thought this had to do with fuel delivery, not the solenoid, so I would never have thought to turn the ignition on first. I will try that tonight to see if to helps.

This may sound funny, and hopefully not condescending...

Do you know how to properly start a 72, and how the solenoid on the carb works? Given how long you have owned it, I suspect so.

As a point of information for those who wonder:
You have to turn the key to ON before you pump the throttle, hot or cold.
When cold, go ahead and pump it twice. When hot, you only have to pump it once, or even half way. The goal with the sequence is to lift the linkage off the solenoid while it is engaged (powered on) so it can then hold the throttle slightly open at the proper position. Now you can start the car. If you attempt to start it with the throttle down (solenoid not holding it open), it won't start easily or sometimes at all.

Most people pump the throttle twice then try to start the car. If so, the throttle is closed and it's much tougher. All of this is assuming that your solenoid is properly being used to set the idle speed, and not the screw on the carburetor.

Even if you are starting it properly, you might want to verify that the solenoid is actually working and didn't break in the last few months if this is a newer problem.

Patrick

[Mark E.]

Re: 1st engine start great - 2nd start not so good

Not to highjack this thread, but thanks for posting this. I have a stock SB 72 and it is just the opposite. I have no trouble starting when it is warmed up, but cold starts are difficult. I have been read in the owners manual where it says to pump the accelerator, but I did not know that the key needed to be on. I thought this had to do with fuel delivery, not the solenoid, so I would never have thought to turn the ignition on first. I will try that tonight to see if to helps.

Don, Patrick,

For Quadrajet equipped engines, during cold starts it does not matter if the ignition is on or off while pumping the accelerator. When the accelerator is depressed, the choke closes which engages the fast idle cam. So the fast idle cam, not the energized idle solenoid, sets initial fast idle speed. During fast idle, the idle solenoid isn't touching the linkage.

I suspect this is the case for Holley equipped engines too, but I'm not sure. (I don't currently own one of these.)

Don,

If by "cold starts are difficult" you mean the engine must crank awhile before firing, likely causes include:

- The choke isn't set properly before cranking. Read the owner's manual. (From your note, I gather this isn't the issue here.)

- Choke not working/adjusted properly

- Fuel bowl is empty. Which means the engine must crank awhile to fill the fuel bowl before it will start. If this only happens after the engine hasn't been started in several days, a likely cause is fuel evaporation. Today's ethanol laced fuel evaporates more quickly than straight gasoline and we don't drive these cars as frequently than in the past, so a "cold cranking before start" situation happens more frequently today. If hard starting is accompanied by black exhaust smoke, check for an internal fuel bowl leak (leaking fuel bowl plugs are a common problem with Q-Jets).

[Don B.]

Re: 1st engine start great - 2nd start not so good

This sounds like it is the issue because I normally do not start the car more than once or twice a month. I guess it is something that I have to live with. The thing that worries me is that that the starter may go bad.. and it is original to the car. After it has ran for a while, it cranks up very easily, even after it has set for a while; for example in a car show. I will have trouble cranking it in the morning, then go to the show and the car sits all day, then it fires right up when time to leave. Other than starting it up every day (which I cannot do) I guess there is nothing I can do. Back in the day when I drove these old cars, this was never an issue.. but there was no such thing as ethanol then.

Don, Patrick,

- Fuel bowl is empty. Which means the engine must crank awhile to fill the fuel bowl before it will start. If this only happens after the engine hasn't been started in several days, a likely cause is fuel evaporation. Today's ethanol laced fuel evaporates more quickly than straight gasoline and we don't drive these cars as frequently than in the past, so a "cold cranking before start" situation happens more frequently today. .

[Jerome P.]

Re: 1st engine start great - 2nd start not so good

I tried your suggested HOT and COLD starts, same result as described in my initial post. Cold startup - starts immediately. Hot restart after 10 minutes of total shut down - starts, but hesitates.